Home

Untitled - sinclair

1. gt 2 2 gt gt expression gt gt gt NOT gt factor gt See EXPRESSION in Section 1 13 and FUNCTION in Section 3 for more details 1 11 TERM gt factor gt gd og 1 DIV MOD AND factor lt The lowerbound of a set is always zero and the set size is always the maximum of the base type of the set Thus a SET OF CHAR always occupies 32 bytes a possible 256 elements one bit for each element Similarly a SET OF 0 10 is equivalent to SET OF 0 255 1 12 SIMPLE EXPRESSION The same comments made in Section 1 11 concerning sets apply to simple expressions 1 13 EXPRESSION simple expression gt Ld 1 1 tot lt gt lt gt lt gt tt t gd Ig gt simple expression When using IN the set attributes are the full range of the type of the simple expression with the exception of integer arguments for which the attributes are taken as if 0 255 had been encountered The above syntax applies when comparing strings of the same length pointers and all scalar types Sets may be compared using gt lt lt gt or Pointers m
2. The text existing within the line range n lt x lt m is searched for an occurrence of the string f the find string If such an occurrence is found then the relevant text line is displayed and the Edit mode is entered see below You may then use commands within the Edit mode to search for subsequent occurrences of the string f within the defined line range or to substitute the string s the substitute string for the current occurrence of f and then search for the next occurrence of f see below for more details Note that the line range and the two strings may have been set up previously by any other command so that it may only be necessary to enter F to initiate the search see the example in Section 4 3 for clarification Command Edit the line with line number n If does not exist then no action is taken otherwise the line is copied into a buffer and displayed on the screen with the line number the line number is displayed again underneath the line and the Edit mode is entered All subsequent editing takes place within the buffer and not in the text itself thus the original line can be recovered at any time In this mode a pointer is imagined moving through the line starting at the first character and various sub commands are supported which allow you to edit the line The sub commands are space increment the text pointer by one i e point to the next character the line You cannot step beyond the end of th
3. 2 3 6 2 SUCC X X may be of any scalar type except real and SUCC X returns the successor of X Examples SUCC A returns 5 57 returns 6 2 3 6 3 PRED X X may be of any scalar type except real the result of the function is the predecessor of X Examples PRED j returns i PRED TRUE returns FALSE 2 3 6 4 ODD X X must be of type integer ODD returns a Boolean result which is TRUE if X is odd and FALSE if X is even 2 3 6 5 ADDR V This function takes a variable identifier of any type as parameter and returns an integer result which is the memory address of the variable identifier V For information on how variables are held at runtime within HiSoft Pascal 4 see Appendix 3 For an example of the use of ADDR see Appendix 4 2 3 6 6 PEEK X T The first parameter of this function is of type integer and is used to specify a memory address see Section 2 3 5 5 The second argument is a type this is the result type of the function PEEK is used to retrieve data from the memory of the computer and the result may be of any type In all PEEK and POKE the opposite of PEEK operations data is moved in HiSoft Pascal 4 s own internal representation detailed in Appendix 3 For example if the memory from 5000 onwards contains the values 50 61 73 63 61 6C in hexadecimal then WRITE PEEK 5000 ARRAY 1 6 OF CHAR gives Pascal WRITE PEEK 5000 CHAR gives P WRITE PEEK 5000 INTEGER gives
4. This procedure is used to load from tape variable etc that have been saved using TOUT NAME is of type ARRAY 1 8 of CHAR and START is of type INTEGER The tape is searched for a file called NAME which is then loaded at memory address START The number of bytes to load is taken from the tape saved on the tape by TOUT E g to load the variable saved in the example in Section 2 3 5 8 above use TIN VAR ADDR V Because source files are recorded by the editor using the same format as that used by TIN and TOUT TIN may be used to load text files into ARRAYs of CHAR for processing see the HP4T Alteration Guide See Appendix 4 for an example of the use of TIN 2 3 5 10 OUT P C This procedure is used to directly access the Z80 s output ports without using the procedure INLINE The value of the integer parameter P is loaded in to the BC register then the character parameter C is loaded in to the A register and the assembly instruction OUT C A is executed E g OUT 1 A outputs the character to the 280 port 1 2 3 6 Further Predefined Functions 2 3 6 1 RANDOM This returns a pseudo random number between 0 and 255 inclusive Although this routine is very fast it gives poor results when used repeatedly within loops that do not contain operations If the user requires better results than this function yields then he she should write a routine either in Pascal or machine code tailored to the particular application
5. and as usual we welcome any correspondence regarding this document CONTENTS 0 PRELIMINARIES Getting Started Scope of this Manual Compiling and Running Strong TYPEing 1 SYNTAX and SEMANTICS ABL LA LA LA LA LA LA N IDENTIFIER UNSIGNED INTEGER UNSIGNED NUMBER UNSIGNED CONSTANT CONSTANT SIMPLE TYPE TYPE ARRAY s and SETs POINTERS RECORDs FIELD LIST VARIABLE FACTOR TERM SIMPLE EXPRESSION EXPRESSION PARAMETER LIST STATEMENT BLOCK PROGRAM PREDEFINED IDENTIFIERS NNNNNNNNNNNNN C2 00000000 CO lO CONSTANTS TYPES PROCEDURES and FUNCTIONS Input and Output Procedures WRITE WRITELN PAGE READ READLN Input Functions EOLN INCH Transfer Functions TRUNC X ROUND X ENTIER X ORD X CHR X 2 3 4 Arithmetic Functions 2 3 4 1 ABS X 2 3 4 2 SQR X 2 3 4 3 SQRT X 2 3 4 4 FRAC X 2 3 4 5 SIN X 2 3 4 6 COS X 2 3 4 7 TAN X 2 3 4 8 ARCTAN X 2 3 4 9 EXP X 2 3 4 10 LN X 2 3 5 Further Predefined Procedures 2 3 5 1 NEW p 2 3 5 2 MARK v1 2 3 5 3 RELEASE v1 2354 INLINE C1 C2 2 3 5 5 USER V 2 3 5 6 HALT 2 3 5 7 POKE X V 2 3 5 8 TOUT NAME START SIZE 2359 TIN NAME START 2 3 5 10 OUT P C 2 3 6 Further Predefined Functions 2 3 6 1 RANDOM 2 3 6 2 SUCC X 2 3 6 3 PRED
6. cassette also suitable for microdrives _ 1 Disciple format diskette 1 Opus Discovery format diskette HiSoft PASCAL 4 V1 5 1983 21 January 1985 PRODUCT APPLICATION NOTE PS 1 1 ZX SPECTRUM SOUND AND GRAFICS WITH HiSoft PASCAL 4T This note gives details on controlling the sound and graphics capabilities of the ZX SPECTRUM using Pascal procedures from within HiSoft Pascal 41 1 Sound The following two procedures defined in the order given below are required to produce sound with This procedure uses machine code to pick up its parameters and then passes them to the BEEP routine within the SPECTRUM PROCEDURE BEEPER A B INTEGER BEGIN INLINE ZDD 6E 2 00 66 3 LD L IX 2 LD H IX 3 00 5E 4 00 56 5 LD E IX 4 LD D IX 5 CD B5 3 F3 385 DI END This procedure traps a frequency of zero which it converts into a period of silence For non zero frequencies the frequency and length of the note are approximately converted to the values required by the SPECTRUM ROM routine and this is then called via BEEPER PROCEDURE BEEP Freq INTEGER Length REAL VAR INTEGER BEGIN IF Freq 0 THEN FOR 1 1 TO ENTIER 12000 Length DO ELSE BEEPER ENTIER Freq Length ENTIER 437500 Freq 30 125 FOR 1 1 TO 100 DO short delay between notes END Example of the use of BEEP 262 0 5 sounds middle C for 0 5
7. 129 CatLoo 130 131 132 133 134 135 135 127 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 NotPri 159 150 161 162 123 154 155 166 147 168 169 170 m CR ini shed LD LD 4N STRIJ H rst 8 DEFB OPEM f CALL Space PRINT JX4RECFLG JR NotPrint LD D CALL CONOUT JR CatBack PUSH Por DE LD H 82 ADD HL DE EX LD A 06 INC DE HL LD LD ADD HL BC LD CALL 5 A HL CONOUT EB32 23 EB33 066 EB3 5E EBS 23 EB38 56 EB3 EBSC 1811 EBJE FEO3 40 2000 42 5 45 25 44 58 45 25 CDA5EB 292349735 5 171 CALL Space 172 EX 173 L AC 174 GR A 175 JR NZ NotProg 176 INC 177 ING HL 178 ING HL 179 INC HL 180 LD 181 INC HL 182 LD 0D HL 183 INC HL 184 CALL DEOUTS 185 LD 188 INC 187 LD 0 HL 188 CALL DEOUTS 189 JR CatBack 190 NotPro 3 191 JR 192 E HL 195 INC HL 194 LD HL 195 INC 196 CALL DEQUTS 197 LD 199 INC HL 199 LD 200 CALL DEOUTS 201 CatBac RST B 202 DEFB CLOSE 203 HL 204 BC 205 CatLoop 206 JP 207 208 CatEnd POP BC 209 DEC HL 210 LD 5 211 CALL WRstring 212 EXX 213 POP HL 214 EXX 215 LO 216 RET 217 218 j0utput DE in decimal 219 220
8. 13 2 b 1504 1655 553 500 5008 5208 520 ASCE 22 23 2 7297 50000 BasEnt HL D H jEquates 10 000p 12 0002 13 PRINT EDU 0043 14 RECFLG EDU 1 1504 16 WAIT EDU 1455 17 MAKE 5 EQU 18 516 19 STRMG EQU 20 ERR NR EDU SCAF 21 CHANG ERU 5052 22 PROG EGU 23 5 24 STRI EQU 5008 25 5 STRI EDU 5CDA 26 STRI EQU 5005 27 T_5TR1 EQU 28 HD 00 EQU 5CE7 29 HD 0b EQ 509 30 00 EOU 31 Hb OF SCED 32H 11 EQU 3 0022 OPEN M EQU 0023 35 CLOSE EQU 0031 EQU 0032 7 SHADOW EQU 38 39 GENS3I2 only 40 140 41 Nuniof L LM ORG 45 46 BASIC entry point 47 1817 48 JR 49 i El 52 5 Eaad 50 LD EL EEEEEEE EA7F FD213A3C EAGS 21CSED 465 0534 EA E 09 24525 EABE 28 ES EAPO 010800 EARS 0518 EAMG 2191 8 BAG 01 05 EAD AGC 73 EAD 23 72 23 EMO EB ERAL 21FDEB EAM 010900 EA EDBO EAA El EAAA 23 EAAD EDABAFSC EAAF 87 ED42 EAB2 22325C EARS 09 EARS ES EAB 09 CF EAB 21 5 PUSH 56 LD HL NUMloff 57 ADD HL DE 58 LD A HL y INC HL 60 OR JR NuaSet LD 63 NumBet AND 100001111 LD 65 LD LD DRIVE H 7 68 j Initialise 6 70 BasEnt LD HL SPA
9. After the interface program has been loaded the screen will go blank the computer is now automatically searching for the compiler code Press BREAK simply the SPACE bar will do to abort the search once the interface program has been loaded Stop the tape and do not rewind it 2 2 Load the code of the compiler run times and editor by typing LOAD HP4S CODE and restart the tape Remember you use keyword entry for LOAD and CODE 2 3 Now load a separate blank tape into your tape recorder you going to record the new HP4S master on this Type SAVE HP4S LINE 1 to save the BASIC interface program so that it automatically executes Set your tape recorder into recording mode and proceed as normal to record on tape 2 4 When the dump of the BASIC interface program has finished leave the tape recorder in recording mode and type SAVE HP4S CODE 24598 21105 This will save the compiler run times and editor on the tape 2 5 You have now created a new master tape which you can use in exactly the same way as the tape supplied by HiSoft You are advised to make one copy and then store the HiSoft master tape in a safe place away from magnetic fields and damp Note that you are authorized by HiSoft to make only one working copy Please do not hesitate to contact us if you experience any difficulty with HiSoft Pascal 4 we can only solve the problems if we know what they are HiSoft PASCAL 4 VERSION 1 4 The release number of HiSof
10. ENTIER 6 5 returns 7 ENTIER 11 7 returns 11 Note ENTIER is not a Standard Pascal function but is the equivalent of BASIC s INT It is useful when writing fast routines for many mathematical applications 2 3 3 4 ORD X X may be of any scalar type except real The value returned is an integer representing the ordinal number of the value of X within the set defining the type of X If X is of type integer then ORD X X this should normally be avoided Examples ORD a returns 97 ORD returns 64 2 3 3 5 CHR X X must be of type integer CHR returns a character value corresponding to the ASCII value of X Examples CHR 49 returns 1 CHR 91 returns 2 3 4 Arithmetic Functions In all the functions within this sub section the parameter X must be of type real or integer 2 3 4 1 ABS X Returns the absolute value of X e g ABS 4 5 gives 4 5 The result is of the same type as X 2 3 4 2 SQR X Returns the value X X i e the square of X The result is of the same type as X 2 3 4 3 SQRT X Returns the square root of X the returned value is always of type real A Maths Call Error is generated if the argument X is negative 2 3 4 4 FRAC X Returns the fractional part of X FRAC X X ENTIER X As with ENTIER this function is useful for writing many fast mathematical routines Examples FRAC 1 5 returns 0 5 FRAC 12 56 returns 0 44 2 3 4 5 SIN X Returns the sine of X where X is in radian
11. She He could do this by VAR A B ARRAY C OF INTEGER and now the user can freely assign A to B and vice versa since only one TYPE record has been created Although on the surface this name equivalence approach may seem a little complicated in general it leads to fewer programming errors since it requires more initial thought from the programmer 1 SYNTAX AND SEMANTICS This section details the syntax and the semantics of HiSoft Pascal 4 unless otherwise stated the implementation is as specified in the Pascal User Manual and Report Second Edition Jensen Wirth 1 1 IDENTIFIER letter lt gt gt letter gt Only the first 10 characters of an identifier are treated as significant Identifiers may contain lower or upper case letters Lower case is not converted to upper case so that the identifiers HELLO HELIo and hello are all different Reserved words and pre definded identifiers may only be entered in upper case 1 2 UNSIGNED INTEGER 13 UNSIGNED NUMBER ee ee pee ORC NICE gt gt gt unsign integ gt gt digit gt E gt unsign integ gt lt gt lt gt gt hexadecimal digit gt Integers have an absolute value less than or equal to 32767 in PASCAL 4 Large
12. then the runtime error Number too large will be issued and execution terminated If the first character read after spaces and end of line characters have been skipped is not a digit or a sign or then a runtime error Number expected will be reported and the program aborted 4 V is of type real Here a series of characters representing a real number according to the syntax of Section 1 3 will be read All leading spaces and end of line markers are skipped and as for integers above the first character afterwards must be a digit or a sign If the number read is too large or too small see Section 1 3 then an Overflow error will be reported if E is present without a following sign or digit then Exponent expected error will be generated and if a decimal point is present without a subsequent digit then a Number expected error will be given Reals like integers may be read immediately see 1 and 3 above 2 3 1 5 READLN READLN V1 V2 Vn is equivalent to BEGIN READ V1 V2 READLN END READLN simply read in a new buffer from the keyboard while typing in the buffer you may use the various control functions detailed in Section 0 0 Thus EOLN becomes FALSE after the execution of READLN unless the next line is blank READLN may be used to skip the blank line which is present at the beginning of the execution of the object code i e it has the effect of reading in a new buffer This will be us
13. 24912 WRITE PEEK 5000 REAL gives 2 46227E 29 see Appendix 3 for more details on the representation of types within HiSoft Pascal 4 2 3 6 7 SIZE V The parameter of this function is a variable The integer result is the amount of storage taken up by that variable in bytes 2 3 6 8 INP P INP is used to access the Z80 s ports directly without using the procedure INLINE The value of the integer parameter P is loaded into the BC register and the character result of the function is obtained by executing the assembly language instruction IN A C 3 COMMENTS AND COMPILER OPTIONS 3 1 Comments comment may occur between any two reserved words numbers identifiers or special symbols see Appendix 2 comment starts with a character or the character pair Unless the next character is a all characters are ignored until the next character or character pair If a was found then the compiler looks for a series of compiler options see below after which characters are skipped until a or is found 3 2 Compiler Options The syntax for specifying compiler options is gt gt letter gt M The following options are available Option L Controls the listing of the program text and object code address by the compiler If L then a full listing is given If L then lines are only listed when an error is detected DE
14. 390 UNTIL FALSE Use CC to exit 400 END 10 Program to show the use of recursion 20 30 PROGRAM FACTOR 40 50 This program calculates the factorial of a number input 60 from the keyboard 1 using recursion and 2 using an 70 iterative method 80 TYPE 90 POSINT 0 MAXINT 100 110 VAR 120 METHOD CHAR 130 NUMBER POSINT 140 150 Recursive algorithm 160 170 FUNCTION RFAC N POSINT INTEGER 180 190 VARF POSINT 200 210 BEGIN 220 IF N gt 1 THEN RFAC N 1 invoked times 230 ELSE 1 240 RFAC F 250 END 260 270 Iterative solution 280 290 FUNCTION IFAC N POSINT INTEGER 300 310 VAR I F POSINT 320 BEGIN 330 1 340 FORI 2TONDOF F l Simple Loop 350 IFAC F 360 END 370 380 BEGIN 390 REPEAT 400 WRITE Give method or R and number 410 READLN 420 READ METHOD NUMBER 430 IF METHOD R 440 THEN WRITELN NUMBER RFAC NUMBER 450 ELSE WRITELN NUMBER FAC NUMBER 460 UNTIL NUMBER 0 470 END 10 Program to show how to get your hands dirty 20 i e how to modify Pascal variables using machine code 30 Demonstrates PEEK POKE ADDR and INLINE 40 50 PROGRAM divmult2 60 70 VAR r REAL 80 90 FUNCTION divby2 x REAL REAL X Function to divide 100 by 2 quickly 110 VAR i INTEGER 120 BEGIN 130 ADDR x 1 Point to the exponent of x 140 POKE i PRED PEEK i
15. 95 instead Line 190 Noswapss should be Noswaps Also the variable Numbers has been declared but all references are to Number Finally the BOLEAN variable Noswaps has not been declared To put all this right we can proceed as follows F60 200 Number Numbers and then use sub command S repeatedly E10 then the sequence X RETURN RETURN E30 then K C 1 RETURN RETURN F100 100 Size Size 1 followed by the sub command 5 M110 95 5 110 followed by RETURN E190 then X DELETE RETURN RETURN 65 Noswaps BOOLEAN N10 10 to renumber in steps of 10 You are strongly recommended to work through the above example actually using the editor you may find it a little cumbersome at first if you have been used to screen editors but it should not take long to adapt Appendix 1 ERRORS A 1 1 Error numbers generated by the compiler Number too large Semi colon expected Undeclared identifier Identifier expected Use not in a constant declaration z expected This identifier cannot begin a statement expected expected 10 Wrong type 11 expected 12 Factor expected 13 Constant expected 14 This identifier is not a constant 15 THEN expected 16 DO expected 17 TO or DOWNTO expected 18 expected 19 Cannot write this type of expression 20 OF expected 21 expected 22 expected 23 PROGRAM expected 24 Variable expected since para
16. CHAR Decrement the exponent of x 150 see Appendix 3 1 3 160 divby2 x 170 END 180 190 FUNCTION multby2 x REAL REAL Function to multiply by 200 by 2 quickly 210 BEGIN 220 INLINE DD 34 3 INC IX 3 the exponent 230 of x see Appendix 3 2 240 multby2 x 250 END 260 270 BEGIN 280 REPEAT 290 WRITE Enter the number 300 READ r No need for READLN see 310 Section 2 3 1 4 320 330 WRITELN divided by two is divby2 r 7 2 340 WRITELN r multiplied by two is multby2 r 7 2 350 UNTIL r 0 360 END BIBLIOGRAPHY K Jensen and PASCAL USER MANUAL AND REPORT N Wirth Springer Verlag 1975 W Findlay and PASCAL AN INTRODUCTION TO SYSTEMATIC D A Watt PROGRAMMING Pitman Publishing 1978 J Tiberghien THE PASCAL HANDBOOK SYBEX 1981 J Welsh and INTRODUCTION TO PASCAL J Elder The first and third books above are useful for reference purposes whereas the second and fourth books are introductions to the language and aimed towards beginners
17. IX 2 e g PROCEDURE test i REAL j INTEGER then j allocated first is at IX 2 and IX 3 iis at IX 4 IX 5 IX 6 and 1 7 Variable parameters are treated just like value parameters except that they are always allocated 2 bytes and these 2 bytes contain the address of the variable e g PROCEDURE test i INTEGER VAR x REAL then the reference to x is placed at IX 2 and IX 3 these locations contain the address where x is stored The value of i is at 1 4 and 1 5 Returned values of functions are placed above the first parameter in memory e g FUNCTION test i INTEGER REAL then i is at IX 2 and IX 3 and space is reserved for the returned value at IX 4 IX 5 IX 6 and IX 7 Appendix 4 SOME EXAMPLE HP4T PROGRAMS The following programs should be studied carefully if you are in any doubt as to how to program in HiSoft Pascal 4T Program to illustrate the use of TIN and TOUT The program constructs a very simple telephone directory on tape and then reads it back You should write any searching required PROGRAM TAPE CONST Size 10 Note that Size is in upper and lower case not SIZE TYPE Entry RECORD Name ARRAY 1 10 OF CHAR Number ARRAY 1 10 OF CHAR END VAR Directory ARRAY 1 Size OF Entry INTEGER BEGIN Set up the directory FOR 1 1 TO Size DO BEGIN WITH Directory l DO BEGIN WRITE Name please READLN READ Name WRITELN WRITE Number pleas
18. RECORDS in general 1 8 FIELD LIST Used in conjunction with RECORDS see Section 1 7 4 above and Appendix 4 for an example 1 9 VARIABLE gt variable identifier gt lt lt gt gt field identifier gt gt expression gt gt 1 eios Two kinds of variables are supported within HiSoft Pascal 4 static and dynamic variables Static variables are explicitly declared through VAR and memory is allocated for them during the entire execution of the block in which they were declared Dynamic variables however are created dynamically during program execution by the procedure NEW They are not declared explicitly and cannot be referenced by an identifier They are referenced indirectly by a static variable of type pointer which contains the address of the dynamic variable See section 1 7 2 and Section 2 for more details of the use of dynamic variables and Appendix 4 for an example When specifying elements of multi dimensional arrays the programmer is not forced to use the same form of index specification in the reference as was used in the declaration this is a change from HiSoft Pascal 3 e g if a variable a is declared as ARRAY 1 10 OF ARRAY 1 10 OF INTEGER then either a 1 1 or a 1 1 may be used to access element 1 1 of the array 1 10 FACTOR gt gt unsigned constant gt
19. any means including photocopying and recording without the written permission of the Copyright holder Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature It is an infringement of the Copyright pertaining to HiSoft Pascal and HiSoft Devpac 3 and associated documentation to copy by any means whatsoever any part of Pascal or Devpac 3 for any reason other than for the purpose of making one security back up copy of the object code HiSoft DEVPAC VERSION 3 2M Loading and Making Back up Copy The loading procedure for both GENS3M2 MDWS3M2 is identical to that given in the Devpac Programmer s manual except that you should allow a little more memory space for both packages Once you have loaded either GENS3M2 or MONS3M2 without executing them you can make a back up copy to either cassette tape or Microdrive cartridge as follows GENS3M2 SAVE GENS3M2 CODE 10034 to cassette SAVE M 1 GENS3M2 CODE 10034 to Microdrive MONS3M2 SAVE MONS3M2 CODE XXXXX 6068 to cassette SAVE M 1 MONS3M2 XXXXX 6068 to Microdrive where XXXXX is the address at which you loaded the program Added Features There are no added Microdrive related features within MONS3M2 the code has simply been altered so that it is possible to single step code that uses the Interface 1 ROM Please note that it in not possible to single step the Interface 1 ROM its
20. cartridge The format of this command is simply O filename where the filename can be up to 8 characters in length If the filename begins with a number followed by a colon then the object code will be saved to the Microdrive specified by the number preceding the colon otherwise the object code is saved to cassette tape You should note that only the last block of code produced by GENS3M2 can be saved in this way i e if you have more than one ORG directive in your program then only the code produced after the last ORG is saved Code must have been produced in the memory of the SPECTRUM before it can be saved using O The Editor V command This command has been modified to display the current delimiter a comma initially as well as the default line numbers and strings It is useful to know what delimiter is if you have inadvertently changed it using the 5 command 4 Extended CATalogue We present below an assembly listing of a program that produces a CATalogue of a Microdrive cartridge similar to that produced by BASIC s CAT but with extra information viz Type of files D for a data or print type file P for a program file B for a CODE file S for a string array N for a numeric array Also for a CODE file its length and start address are displayed in decimal while for a program file it s length and auto execution address are displayed in decimal To use the program either type in the hex codes direc
21. form and then put back into the file in a tokenised form this may of course take a little time to perform A line range must be specified or the previously entered values will be assumed Command 5 This command allows you to change the delimiter which is taken as separating the arguments the command line On entry to the editor the comma is taken as the delimiter this may be changed by the use of the S command to the first character of the specified string d Remember that once you have defined a new delimiter it must be used even within the S command until another one is specified Note that the separator may not be a space 4 3 Example of the use of the Editor Let us assume that you have typed in the following program using 110 10 10 PROGRAM BUBBLESORT 20 CONST 30 Size 2000 40 VAR 50 Numbers ARRAY 1 Size OF INTEGER 60 Temp INTEGER 70 BEGIN 80 1 1 TO Size DO Number l RANDOM 90 REPEAT 100 FORI 1 TO Size DO 110 Noswaps TRUE 120 IF gt 1 THEN 130 140 Temp 150 Number l 1 160 1 Temp 170 Noswaps FALSE 180 END 190 UNTIL Noswaps 200 END This program has a number of errors which are as follows Line 10 Missing semi colon Line 30 Not really an error but say we want a size of 100 Line 100 Size should be Size 1 Line 110 This should be at line
22. line marker a CHR 13 character then the function EOLN will return the value TRUE and a new line of text is read in from the keyboard When a read operation is subsequently performed then the text window will be positioned at the start of the new line Important note Note that EOLN is TRUE at the start of the program This means that if the first READ is of type character then a CHR 13 value will be returned followed by the reading in of a new line from the keyboard a subsequent read of type character will return the first character from this new line assuming it is not blank See also the procedure READLN below 2 V is of type string A string of characters may be read using READ andin this case a series of characters will be read until the number of characters defined by the string has been read or EOLN TRUE If the string is not filled by the read i e If end of line is reached before the whole string has been assigned then the end of the string is filled with null CHR 0 characters this enables the programmer to evaluate the length of the string that was read The note concerning in 1 above also applies here 3 V is of type integer In this case a series of characters which represent an integer as defined in Section 1 3 is read All preceding blanks and end of line markers are skipped this means that integers may be read immediately cf the note in 1 above If the integer read has an absolute value greater than MAXINT 32767
23. position and then advances the pointer by one You remain in the change sub mode until you press RETURN whence you are taken back to the Edit mode with the pointer positioned after the last character you changed DELETE or BACKSPACE within this sub mode simply decrements the pointer by one i e moves it left while CI has no effect 4 2 4 Tape Commands Text may be saved to tape or loaded from tape using the commands P and G Command P n m s The line range defined by n x m is saved to tape in HPAT format under the file name specified by the string s Remember that these arguments may have been set by a previous command Before entering this command make sure that your tape recorder is switched on and in RECORD mode While the text is being saved the message Busy is displayed Command G s The tape is searched for a file in HPAT tape format and with a file name of s While the search is taking place the message Busy will be displayed If a valid HP4T tape file is found but has the wrong file name then the message Found followed by the file name that was found on the tape is displayed and the search continued Once the correct file name is found then Found will appear on the list device and the file will be loaded into memory If an error is detected during the load then Checksum error is shown and the load aborted If this happens you must rewind the tape press PLAY and type G again If the string s is empty the
24. seconds BEEP 0 1 followed by a one second silence High quality microcomputer SOFTware 2 Graphics Three graphics procedures are given the first plots a given X Y co ordinate whilst the second and third are used to draw lines from the current plotting position to a new position which is defined relative to the current plot position and which then becomes the current plot position Both PLOT and LINE take a BOOLEAN variable ON which if TRUE will cause any point to be plotted regardless of the state of the pixel in that plot position or if FALSE will cause any pixel already present at the plot position to be flipped i e if on it becomes kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk There are occasions where it is useful to output directly through the SPECTRUM ROM RST 10 routine rather than use WRITE LN For example when using the PRINT AT control code this code should be followed by two 8 bit values giving the X Y co ordinate to which the print position is to be changed However if this is done using a Pascal WRITE statement then certain values of X and Y e g 8 which is interpreted by HPAT as BACKSPACE will not be passed to the ROM and thus the print position will not be correctly modified You can overcome this problem by using the following procedure kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk SPOUT outputs the character passed as a parameter directly WYGRUV
25. set of ASCII values with 256 elements To maintain compatibility with Standard Pascal the null character is not represented as instead CHR 0 should be used 15 CONSTANT Em oM inn gt constant identifier EE su E ERST gt gt unsigned number lt gt gt character gt The non standard CHR construct is provided here so that constants may be used for control characters In this case the constant in parentheses must be of type integer E g CONST bs CHR 10 cr CHR 13 1 6 SIMPLE TYPE gt gt type identifier gt gt gt identifier gt gt 1 gt gt constant gt gt constant Scalar enumerated types identifier identifier may not have more than 256 elements 1 7 TYPE gt gt simple type gt gt gt type identifier gt V lt PACKED lt The reserved word PACKED is accepted ignored since packing already takes place for arrays of characters etc The only case in which the packing of arrays would be advantageous is with an array of Booleans but this is more naturally expressed as a set when pack
26. the X command Now use the relevant operating system command to dump this block of memory to tape Note that you will not use the HP4T loader to load the compiler etc When saved in this way instead you should use the relevant operating system load from tape command and then execute a cold start into the editor as given in your Implementation Note Note ZX SPECTRUM users cannot use the above method of making a copy and should consult their Implementation Note for details of making a working copy of As usual HiSoft welcomes any queries concerning this note High quality microcomputer SOFTware HiSoft PASCAL 4T VERSION 1 5 As from 1 April 1983 the version number of HiSoft Pascal 4T will be 1 5 Owners of previous versions of may upgrade to version 1 5 by returning their old tape together with a handling charge of pound 3 VAT The differences between version 1 4 and version 1 5 are as follows 1 Functions may now return a POINTER result 2 A bug in the pre defined procedure NEW which occasionally resulted in the incorrect allocation of memory for a dynamic variable has been fixed 3 A new editor command has been incorporated The V command takes no arguments and simply displays the current default values of the line range the Find string and the Substitute string The current default line range is shown first followed by the two strings which may be empty on separate lines It should be remember
27. the compilation will be moved to the end of the run times destroying the compiler and then the run times and the object code will be dumped out to tape with a file name equal to that previously defined for the find string You may then at a later stage load this file into memory using the loader whereupon it will automatically execute the object program Note that object code is located at and moved to the end of the run times so that after a T ranslate you will need to reload the compiler however this should present no problems since you are only likely to T ranslate a program when it is fully working If you decide not to continue with the dump to tape then simply type any character other than Y to the Ok prompt control is returned to the editor which will still function perfectly since the object code was not moved 4 2 6 Other Commands Command B This simply returns control to the operating system For details of how to re enter the compiler refer to the Alteration Guide and your Implementation Note Command O n m Remember that text is held in memory in a tokenised form with leading spaces shortened into a one character count and all Reserved Words reduced to a one character token However if you have somehow got some text in memory perhaps from another editor which is not tokenised then you can use the O command to tokenise it for you Text is read into a buffer in an expanded
28. 0 RET instruction C9 and must preserve the IX register 2 3 5 6 HALT This procedure causes program execution to stop with the message Halt at the where XXXX is the hexadecimal memory address of the location where the HALT was issued Together with a compilation listing HALT may be used to determine which of two or more paths through a program are maked This will normally be used during de bugging 2 3 5 7 POKE X V POKE stores the expression V in the computer s memory address X X is of type integer and V can be of any type except SET See Section 2 3 5 5 above for a discussion of the use of integers to represent memory addresses Examples 6000 places 41 at location 6000 POKE 16384 3 6E3 places 00 OE 80 70 in hexadecimal at location 000 2 3 5 8 TOUT NAME START SIZE TOUT is the procedure which is used to save variables on tape The first parameter is of type ARRAY 1 8 OF CHAR and is the name of the file to be saved SIZE bytes of memory are dumped starting at the address START Both these parameters are of type INTEGER E g to save the variable V to tape under the name VAR use TOUT VAR ADDR V SIZE V The use of actual memory addresses gives the user far more flexibility than just the ability to save arrays For example if a system has a memory mapped screen entire screen fulls may be saved directly See Appendix 4 for an example of the use of TOUT 2 3 5 9 TIN NAME START
29. 2266 266 266 So remembering that HL and DE are used to hold real numbers then we would have to load the registers in the following way to represent each of the above numbers 2 LD HL 4000 LD DE 0100 1 LD HL 4000 LD DE 0000 12 5 LD HL E400 LD DE 0300 0 1 LD HL 6666 LD DE ZFC66 The last example shows why calculations involving binary fractions can be inaccurate 0 1 cannot be accurately represented as a binary fraction to a finite number of decimal places N B reals are stored in memory in order ED LH A 3 1 4 Records and Arrays Records use the same amount of storage as the total of their components Arrays if n number of elements in the array and s size of each element then the number of bytes occupied by the array is n s e g an ARRAY 1 10 OF INTEGER requires 10 2 20 bytes an ARRAY 2 12 1 10 OF CHAR has 11 10 110 elements and so requires 110 bytes A 3 1 5 Sets Sets are stored as bit strings and so if the base type has n elements then the number of bytes used is n 1 DIV 8 1 Examples a SET OF CHAR requires 256 1 DIV 8 1 32 bytes a SET OF blue green yellow requires 3 1 DIV 8 1 1 byte A 3 1 6 Pointers Pointers occupy 2 bytes which contain the address in Intel format i e low byte first of the variable to which they point A 3 2 Variable Storage at Runtime There are 3 cases where the user needs information on how variables are stored at runt
30. 27079 294 72696768 74204859 75575674 20313938 EBF7 0000 233 298 SIGNEN EGU 297 EBF9 504 5342 298 DEFM PNSB 233 EBFD C415 300 CIAINF DEFW 1304 EBFF 5 301 00 28002800 302 0800 303 304 jss this value may change with new Interface 303 ECO4 3812 304 CAT 307 208 tisse HE EE FEE Ea 30 310 ECOS 311 POINTE DEFS 2 312 SPACE DEFS 512 313 Pass 2 errors 00 DEFM Copyright Hisoft 1984 DEFW 828 828 11 HiSoft PASCAL VERSION 1 6 Loading and Making a Back up Raw Oonir t 14 To load Pascal 1 6M into the Spectrum simply use LOAD LOAD is on the J key and start your tape recorder Once loaded the program will run automatically and you will be prompted with of RAM refer to Section 0 of the Programmer s Manual for details of how to answer this and the two following questions Normally pressing ENTER in response to the prompts will suffice Once you are the editor mode there will be gt prompt on the left hand side of the screen you make a back up copy of the Pascal by using the B ye command to return to BASIC and then either SAVE HP4TM16 CODE 24598 19736 for cassette tape or SAVE M 1 HP4TM16 CODE 24598 19736 for Microdrive This will save a configured version of the Pascal which you can load back into the machine simply using LOAD CODE or L
31. 768 decimal If you specify so large value that this happens then you will be prompted again for of RAM etc You may optionally include an E before the number after this prompt if you do so then the internal line editor will not be retained for use by the compiler So do this if you wish to use your own editor with the compiler see HPAT Alteration Guide for details on how to do this At this point the compiler and integral editor if retained will be relocated at the end of the symbol table and execution transferred to the supported editor Note throughout this Manual the hash sign decimal 35 hexadecimal 23 shift 37 is replaced by the number sign on all systems which do not use U K ASCII Numbers that are preceded by this symbol are in hexadecimal 0 1 Scope of this manual This manual is not intended to teach you Pascal you are referred to the excellent books given in the Bibliography if you are a newcomer to programming in Pascal This manual is a reference document detailing the particular features of HiSoft Pascal 4 Section 1 gives the syntax and the semantics expected by the compiler Section 2 details the various predefined identifiers that are available within HiSoft Pascal 4 from CONSTants to FUNCTIONS Section 3 contains information on the various compiler options available and also on the format of comments Section 4 shows how to use the line editor which is an integral part of HP4T if y
32. CE 1 LD POINTER HL n LD 73 74 L HL SIGNON 7 LD B SIGNEND SIBNON 7b CALL n 78 jSet up new channel and attach to Stream 4 n 80 LD HL PROG gl DEC HL 82 PUSH HL 85 LD 1 84 CALL SPACE 85 L HL CHi4out Bb POP DE 87 PUSH DE 88 EX 87 LD 90 INC HL 91 LD 92 HL 3 EX LD 95 LD BC 11 2 LDIR 97 HL 98 INC 9 LD CHANS 100 OR A 101 SBC 102 LD STRHS 28 HL 103 104 read in bare catalogue 103 105 EKN 107 PUSH HL 108 109 119 RST 8 DEFB NEWVARS 112 EABA JEQE EABC 32DB85C EABF 2 EAC2 220 5 EACS ZAQsEC EACE 22 05 EACE FB EACC CF EACD 32 210AEC EAD1 0608 EADS CDYAEB EADS OLOF EADS C5 EAD 23 EADA 7E EADB FEOD EADD 2879 EADF 2B EAEO 0608 EAE2 ES EAE3 CDYAEB EAES ES EAE 25 EAEB EB EAE 210 5 EAEC 73 EAED 23 EAEE 72 2 EAF 22D65C EAFS 210000 EAFB 220 5 EAFB FB EAFC CF EAFD 22 EAFE CDBSEB ERO DDCB4354 EBOS 2007 EBO7 3E44 ERO CDACEB EBOC 1841 DDES EP10 01 11 215200 EBI4 19 ERIS EB16 17 13 21F9EB EBIB 4F EBIC 0500 EBIE 09 EBIF 7E EB20 CDACEB 113 114 115 116 117 118 119 120 121 122 LD 4 14 LD LD HL DRIVE LD D STRI H LD LD EI RST DEFB SHADOW 123 jNow process bare catalogue 124 125 126 127 128 CatLi
33. DEDUTS PUSH HL 221 PUSH IX 222 DE HL 223 LD 8 5 224 LD IX TENTAB 225 DEloop 10 1X 224 LD 0 01 1 227 LD 8 1 228 TenLoo INC 2 08 EB 4 77 EB S 23 2208EC 99 EBAC FS EBAD 3E02 CDA2EB EBB2 Fl D7 EBB4 CY EBBS 3E20 EBB7 1BF3 223 230 HL DE 231 JR NC TenLoop 232 ADD HL DE 233 oR 5 234 CALL CONOUT 235 2 INC IX 237 DJNZ DEloop CALL Space 239 POP Ix 240 POP HL 241 RET 242 243 Output for Stream 14 244 245 CHi4ou LD HL POINTER 246 LD 247 INC HL 248 LD POINTER HL 249 RET 250 251 jWrite a string of length B from HL 253 WRstri LD 254 CALL CONOUT 255 HL 2 DJNZ WRstring 257 RET 258 259 a stresa 250 261 ChOpen PUSH HL 252 PUSH DE 263 PUSH BC 264 CALL 1601 245 BC 266 POP DE 257 POP HL 258 RET 259 270 Output to stream 2 271 272 CONOUT PUGH 273 LD 4 2 274 CALL ChOpen 275 POP 276 RST 10 277 278 Output a space to stream 2 Space LD A JR Storage EBB 0100 287 DRIVE EBBB 1027E803 287 DEFW 10000 1000 100 10 1 54000400 0100 290 EBCS 00 291 SIGNON DEFB CR DEFM Hisaft Extended CAT Listing 40697347 292 55742043 780874656E 64656420 43415420 46547574 895 57 EBE QD 273 438
34. FAULT Option O Controls whether certain overflow checks are made Integer multiply and divide and all real arithmetic operations are always checked for overflow If O then checks are made on integer addition and subtraction If O then the above checks are not made DEFAULT Option C Controls whether or not keyboard checks are made during object code program execution If C then if CC is pressed then execution will return to with a HALT message see Section 2 3 5 6 This check is made at the beginning of all loops procedures and functions Thus the user may use this facility to detect which loop etc is not terminating correctly during the debugging process It should certainly be disabled if you wish the object program to run quickly If C then the above check is not made DEFAULT Option S Controls whether or not stack checks are made If S then at the beginning of each procedure and function call a check is made to see if the stack will probably overflow in this block If the runtime stack overflows the dynamic variable heap or the program then the message Out of RAM at is displayed and execution aborted Naturally this is not foolproof if a procedure has a large amount of stack usage within itself then the program may crash Alternatively if a function contains very little stack usage while utilizing recursion then it is possible for the function to be halted unnecessarily If S then
35. OAD M 1 HP4TM16 CODE Once you have re loaded it in this way then you must enter HPATM16 via either RANDOMIZE USR 24598 for a cold start destroying any text or RANDOMIZE USR 24603 for a warm start which preserves any existing text You may re enter the Pascal from BASIC using these addresses at any time You should note that HiSoft Pascal Version 1 6M does not have a BASIC loader and thus any reference to this loader in your Implementation Note should be disregarded Specifically to re enter HiSoft Pascal at any time you do not GOTO 9 or GOTO 12as in the Implementation Mode instead you use the cold and warm start addresses given above In addition you should ignore the instructions on making a back up copy given in the Implementation Note use those above instead Also because there is no BASIC interface program the cassette commands P and B take effect immediately and display Busy as stated in the HiSoft Pascal Programmer s Manual We now look at the extra features that have been implemented in HiSoft Pascal Version 1 6M Firstly note that on any return to BASIC from within HP4TM16 the display will first pause waiting for you to hit any key This has been added so that runtime error messages etc may be inspected when running a Translated program The Editor V Command This command has been modified to display the current delimiter initially a comma as well as the default line numbers and strings The Edit
36. ORD FALSE 0 so FALSE is represented by 0 The standard Z80 register used by the compiler for the above is A A 3 1 3 Reals The mantissa exponent form is used similar to that used in standard scientific notation only using binary instead of denary Examples 0 1 2 2 10 or 10 2 2 121 10 or 1 0 2 2 1 1 12 5 1 25 10 or 25 2 1 11001 2 2 3 1 1001 2 when normalized 2 0 1 1 1 1 2 0 4 2 10 40 or m so now we need to do some binary long division 0 0001100 101 0 10000000000000000 101 110 101 1000 101 atthis point we see that the fraction recurs 0 1 2 0 0001100 101 2 2 4 1 1001100 2 answer So how do we use the above results to represent these numbers in the computer Well firstly we reserve 4 bytes of storage for each real in the following format sign normalized mantissa exponent data 23 22 0 7 0 bit P REDE NE L E D register sign the sign of the mantissa 1 O positive normalized mantissa the mantissa normalized to the form 1 XXXXXX with the top bit bit 22 always 1 except when representing zero HL DE 0 exponent the exponent in binary 2 s complement form Thus 2 0 1000000 00000000 00000000 00000001 40 00 00 01 1 0 1000000 00000000 00000000 00000000 40 00 00 00 12 5 1 1100100 00000000 00000000 00000011 E4 00 00 03 0 1 201100110 01100110 01100110 11111100
37. RN See Implementation Note If you enter a number then this is taken to represent the highest RAM location 1 otherwise the first non RAM location is automatically computed The compiler s stack is set to this value and thus you can reserve high memory locations perhaps for extensions to the compiler by deliberately giving a value less than the true top of RAM In the ZX Spectrum version the true top of RAM is taken to be start of the user defined graphics area UDG in the Sinclair manual You will then be prompted with Top of RAM for T Here you can enter a decimal number or default to the of RAM value previously specified What you enter will be taken as the stack when the resultant object code is executed after using the editor T command See Section 4 for details You will need to define a runtime stack different from the top of RAM if for example you have written extensions to the run times and wish to place them safely in high memory locations Finally you will be asked Table size What you enter here specifies the amount of memory to be allocated to the compiler s symbol table Again either enter a positive decimal number followed by RETURN or simply RETURN by itself in which case a default value of available RAM divided by 16 will be taken as the symbol table size In nearly all cases the default value provides more than enough space for symbols The symbol table may not extend above machine address 8000 32
38. T unsigned integer gt function identifier gt procedure identifier gt gt expression gt gt 1 MM 2 gt gt statement gt END gt Pe e gt gt gt ELSE gt statement gt gt WHILE gt expression gt DO gt statement gt gt REPEAT gt statement UNTIL gt expression gt lt gt FOR gt variable identifier gt gt expression gt gt expression gt DO gt statement gt 1 gt WITH gt variable gt DO gt statement gt gt GOTO gt unsigned integer 2 1 16 BLOCK gt gt LABEL gt unsigned integer lt amp I gt FUNCTION gt identifier gt parameter list gt gt type ident gt lt lt block lt lt gt BEGIN gt statement gt END gt eiu lt Note that
39. X 2 3 6 4 ODD X 2 3 6 5 ADDR V 2 3 6 6 PEEK X T 2 3 6 7 SIZE V 2 3 6 8 INP P 3 COMMENTS and COMPILER OPTIONS 3 1 Comments 3 2 Compiler options 4 THE INTEGRAL EDITOR 4 1 Introduction to the Editor 4 2 The Editor Commands 4 2 1 Text Insertion 4 2 2 Text Listing 4 2 3 Text Editing 4 2 4 Tape Commands 4 2 5 Compiling and Running from the Editor 4 2 6 Other Commands 4 3 An Example of the Use of the Editor Appendix 1 ERRORS A 1 1 Error numbers generated by the compiler A 1 2 Runtime Error Messages Appendix2 RESERVED WORDS and PREDEFINED IDENTIFIERS A 2 1 Reserved Words 2 2 Special Symbols A 2 3 Predefined Identifiers Appendix 3 REPRESENTATION and STORAGE A 3 1 Data Representation A 3 1 1 Integers A 3 1 2 Character Booleans and other Scalars A 3 1 3 Reals A 3 1 4 Records and Arrays A 3 1 5 Sets A 3 1 6 Pointers A 3 2 Variable storage at Runtime Appendix4 SOME EXAMPLE HP4T PROGRAMS BIBLIOGRAPHY 0 PRELIMINARIES 0 0 Getting Started HiSoft Pascal 4T HP4T is a fast easy to use and powerful version of the Pascal language as specified in the Pascal User Manual and Report Jensen With Second Edition Omissions from the specification are as follows FILEs are not implemented although variables may be stored on tape A RECORD type may not have a VARIANT part PROCEDUREs and FUNCTIONS are not valid as parameters Many extra functions and procedure
40. _ 60 0 GOTO 61 This label is at the wrong level 62 Undeclared label 63 The parameter of SIZE should be a variable 64 Can only use equality tests for pointers 65 66 67 The only write parameter for integers with two s is e m H 68 Strings may not contain end of line characters 69 The parameter of NEW MARK or RELEASE should be a variable of pointer type 70 The parameter of ADDR should be a variable A 1 2 Runtime error messages When a runtime error is detected then one of the following messages will be displayed followed by at where XXXX is the memory location at which the error occurred Often the source of the error will be obvious if not consult the compilation listing to see where in the program the error occurred using XXXX to cross reference Occasionally this does not give the correct result Halt Overflow Out of RAM by zero also generated by DIV Index too low Index too high Maths Call Error Number too large Number expected 10 Line too long 11 Exponent expected O0 1004o0oN2 Runtime errors result in the program execution being halted Appendix2 RESERVED WORDS AND PREDEFINED IDENTIFIERS A 2 1 Reserved Words AND ARRAY BEGIN CASE CONST DIV DO DOWNTO ELSE END FOR FORWARD FUNCTION GOTO IN LABEL MOD NIL NOT OF OR PACKED PROCEDURE PROGRAM RECORD REPEAT SET THEN TO TYPE UNTIL VAR WHILE WITH A 2 2 Special Sym
41. a the ENTER key CC CAPS SHIFT and 1 EDIT CH DELETE i e CAPS SHIFT and 0 DELETE via CAPS SHIFT and 8 gt CP via CHR 16 in a WRITE or WRITELN statement CX via CAPS SHIFT and 5 lt CS via CAPS SHIFT and SPACE The ZX SPECTRUM keyword entry scheme is not supported we see this as a positive advantage instead all text must be inserted using the normal alphanumeric keys Using SYMBOL SHIFT and key except 1 will always reach the ASCII symbol associated with that key and not the keyword e g SYMBOL SHIFT T gives gt and SYMBOL SHIFT gives You must not use the single symbols lt lt gt and gt instead these should be entered as a combination of the symbols lt gt and The editor comes up in upper case mode this may be toggled in the normal way using CAPS SHIFT and 2 You have control over the temporary attributes of the various character position on the screen through the use of the standard control codes e g WRITE CHR 17 CHR 4 will make the paper green but you cannot change the permanent attributes If while using these control codes an invalid sequence is detected then the message System Call Error will be displayed and the execution aborted When you dump out text or object code to tape the message Start tape then press any key will be displayed twice you must respond to it each time There is no need to save the loader since an automatic loader is always dumped with the o
42. ay only be compared using and lt gt 1 14 PARAMETER LIST A type identifier must be used following the colon otherwise ERROR 44 will result Variable parameters as well as value parameters are fully supported Procedures and functions are not valid as parameters 1 15 STATEMENT Refer to the syntax diagram on page below Assignment statements See section 1 7 for information on which assignment statements are illegal CASE statements An entirely null case list is not allowed i e CASE OF END will generate an error 13 The ELSE clause which is an alternative to END is executed if the selector expression overleaf is not found in one of the case lists constant overleaf If the END terminator is used and the selector is not found then the control is passed to the statement following the END FOR statements The control variable of a FOR statement may only be an unstructured variable not a parameter This is half way between Jensen Wirth and draft ISO standard definitions GOTO statements It is only possible to GOTO a label which is present in the same block as the GOTO statement and at the same level Labels must be declared using the Reserved Word LABEL in the block in which they are used a label consists of at least one and up to four digits When a label is used to mark a statement it must appear at the beginning of the statement and be followed by a colon STATEMEN
43. bject program if you have used the Translate command to save the code and run times on Tape then to load and run the program simply enter LOAD from within BASIC After the execution of the object code has finished you can run it again assuming it has not corrupted anything by entering GOTO 9 to perform a warm start i e preserving the Pascal program or GOTO 12 to do a cold start re initialising the Pascal and clearing any existing Pascal text The ZX Printer is supported via the use of the compiler P option see Section 3 2 of the Programmer s Manual and via CHR 16 in a WRITE or WRITELN statement Note that as a result you cannot use CHR 16 within a WRITE LN statement to specify the INK colour instead you can use CHR 15 to set the INK To make a working copy of HP4S proceed as follows 2 1 Load up the BASIC interface HiSoft Pascal 4 on the SPECTRUM is in two parts an interface to BASIC and the compiler run times etc proper The BASIC interface is recorded first on the master tape followed by the code of the compiler run times and editor Normally the BASIC interface program automatically loads the rest of the code and then auto starts the compiler We must prevent this So load the master HP4S cassette into your tape recorder type LOAD simply using keyword entry and PLAY the tape when the SPECTRUM finds the BASIC interface program header it will display Program HP4S and then load the interface program itself
44. bols The following symbols are used by HiSoft Pascal 4 and have a reserved meaning 7 A 2 3 Predefined Identifiers The following entities may be thought of a declared in a block surrounding the whole program and they are therefore available throughout the program unless re defined by the programmer within an inner block For further information see Section 2 CONST MAXINT 32767 TYPE BOOLEAN FALSE TRUE CHAR expanded ASCII character INTEGER MAXINT MAXINT REAL subset of the real numbers See Section 1 3 PROCEDURE WRITE WRITELN READ READLN PAGE HALT USER POKE INLINE OUT NEW MARK RELEASE TIN TOUT FUNCTION ABS SQR ODD RANDOM ORD SUCC PRED INCH EOLN PEEK CHR SQRT ENTIER ROUND TRUNC FRAC SIN COS TAN ARCTAN EXP LN ADDR SIZE INP Appendix 3 DATA REPRESENTATION AND STORAGE A 3 1 Data Representation The following discussion details how data is represented internally by HiSoft Pascal 4 A 3 1 1 Integers Integers occupy 2 bytes of storage each in 2 s complement form Examples 1 0001 256 0100 256 200 The standard 280 register used by the compiler to hold integers is HL 3 1 2 Characters Booleans and other Scalars These occupy 1 byte of storage each in pure unsigned binary Characters 8 bit extended ASCII is used E 45 T 5B Booleans ORD TRUE 1 so TRUE is represented by 1
45. c UBRO BER HiSoft is pleased to announce ZX Microdrive compatible versions of both Pascal and Devpac version numbers 1 6M and 3 2M respectively These versions are available from the 7 March 1984 and give the user the ability to store and retrieve text files to and from the Microdrives include text from a Microdrive cartridge whilst compiling or assemble and save the resultant object code onto a Microdrive cartridge These releases incorporate enhancements and bug fixes to Versions 1 5M and 3 0M of Pascal and Devpac respectively Any existing customer who purchased Devpac 3M or Pascal 1 5M may exchange their tape e for these new versions for a handling charge of 1 50 82 50 outside the UK To upgrade to these versions from previous versions of Pascal and Devpac please return your original tape with 3 45 4 outside the UK We are working on even more powerful versions of these programs which will include many extra Microdrive related features such as sequential FILE handling for Pascal and easy assembly from Microdrive to Microdrive in one step We shall be announcing these versions when they become available The remainder of this document details the Microdrive extensions to HiSoft Pascal Version 1 6M and HiSoft Devpac Version 3 2M that are currently from 7 March 1984 available C Copyright HiSoft 1984 All Rights Reserved Worldwide No part of this publication may be reproduced or transmitted in any form or by
46. ch v1 points is irrelevant since v1 should only be used with MARK and RELEASE never NEW For an example program using MARK and RELEASE see Appendix 4 2 3 5 3 RELEASE v1 This procedure frees space on the heap for use of dynamic variables The state of the heap is restored to its state when MARK v1 was executed thus effectively destroying all dynamic variables created since the execution of the MARK procedure As such it should be used with great care See above and Appendix 4 for more details 2 3 5 4 INLINE C1 C2 C3 This procedure allows Z80 machine code to be inserted within the Pascal program the values C1 MOD 256 C2 MOD 256 MOD 256 are inserted in the object program at the current location counter address held by the compiler C1 C2 C3 etc are integer constants of which there can be any number Refer to Appendix 4 for an example of the use of INLINE 2 3 5 5 USER V USER is a procedure with one integer argument V The procedure causes a call to be made to the memory address given by V Since HiSoft Pascal 4 holds integers in two s complement form see Appendix 3 then in order to refer to addresses greater than 7FFF 32767 negative values of V must be used For example C000 is 16384 and so USER 16384 would invoke as a call to the memory address 000 However when using a constant to refer to a memory address it is more convenient to use hexadecimal The routine called should finish with a 28
47. ditor or any key to restart the listing If an error is detected during the compilation then the message ERROR will be displayed followed by up arrow which points after the symbol which generated the error and an error number see Appendix 1 The listing will pause hit E to return to EDITOR to edit the line displayed P to return to the editor and edit the previous line if it exists or any other key to continue the compilation If the program terminates incorrectly e g without END then the message more will be displayed and control returned to the editor If the compiler runs out of table space then the message No Table Space will be displayed and control returned to the editor Normally the programmer will then save the program on tape re load the compiler and specify a larger Table size see Section 0 0 If the compilation terminates correctly but contained errors then the number of errors detected will be displayed and the object code deleted If the compilation is successful then the message Run will be displayed if you desire an immediate run of the program then respond with Y otherwise control will be returned to the editor During a run of the object code various runtime error messages may be generated see Appendix 1 You may suspend a run by using CS subsequently use CC to abort the run or any other key to resume the run 0 3 Strong TYPEing Different languages have differen
48. e READLN READ Number WRITELN END END To dump the directory to tape use TOUT Director ADDR Directory SIZE Directory to read the array back to the following TIN Director ADDR Directory now you can process the directory as you wish END 10 Program to list lines of a file in reverse order 20 Shows use of pointers records MARK and RELEASE 30 40 PROGRAM ReverseLine 50 60 TYPE elem RECORD Create linked list structure 70 next elem 80 ch CHAR 90 END 100 link 4elem 110 120 VAR prev cur heap link all pointers to elem 130 140 BEGIN 150 REPEAT do this many times 160 MARK heap assign top of heap to heap 170 prev zNIL points to no variable yet 180 WHILE NOT EOLN DO 190 BEGIN 200 NEW cur create a new dynamic 210 READ cur ch assign its field to one 220 character from file 230 cur next prev this field s pointer addresses 240 prev cur previous record 250 END 260 270 Write out the line backwards by scanning the records 280 setup 290 300 310 WHILE cur lt gt NILDO is first 320 BEGIN 330 WRITE cur ch WRITE this field i e character 340 cur cur next Address previous field 350 END 360 WRITELN 370 RELEASE heap Release dynamic variable space 380 READLN Wait for another line
49. e in the example above you could use the following 10 PROGRAM A 20 BEGIN 30 40 F 1 TEST 50 60 END Note that to include a file from cassette tape you must have used the W editor command to dump out the text in a blocked format whereas with Microdrives you include a text file saved using the normal P ut command Do not try to return to the editor via E or P if there is a compilation error in a file that you are including you must continue the compilation TIN and TOUT Data structures may be saved to cassette or Microdrive using the TIN procedure from within a Pascal program and retrieved using TOUT see Sections 2 3 5 8 and 2 3 5 9 of the HiSoft Pascal Programmer s Manual for details To direct data to or from Microdrives simply start the required filename with a Microdrive number 1 8 inclusive and a colon e g 10 PROGRAM A 20 VAR A B ARRAY 1 20 OF CHAR 30 BEGIN 40 some code to set up the array A 10 50 60 TOUT ADDR A SIZE A 70 80 some more program 90 100 TIN ADDR B 110 etc etc Remember that the number of characters within the TIN or TOUT must be exactly 8 l ranslation of Object Code The editor T command can be used to translate the Pascal object code so that it may be stored on cassette tape or Microdrive Remember that when translating the compiler is deleted and the run times together with the object code are sav
50. e line DELETE or BACKSPACE decrement the text pointer by one to point at the previous character in the line You cannot step backwards beyond the first character in the line CI control function step the text pointer forwards to the next tab position but not beyond the end of the line RETURN end the edit of this line keeping all the changes made Q quit the edit of this line i e leave the edit ignoring all the changes made and leaving the line as it was before the edit was initiated R reload the edit buffer from the text i e forget all changes made on this line and restore the line as it was originally L list the rest of the line being edited i e the remainder of the line beyond the current pointer position You remain in the Edit mode with the pointer re positioned at the start of the line K kill delete the character at the current pointer position Z delete all characters from and including the current pointer position to the end of the line F find the next occurrence of the find string previously defined within a command line see the F command above This sub command will automatically exit the edit on the current line keeping the changes if it does not find another occurrence of the find string in the current line If an occurrence of the find string is detected in a subsequent line within the previously specified line range then the Edit mode will be entered for the line in which the strin
51. ed that certain editor commands like D and N do not use these default values but must have values specified on the command line see the Programmers Manual 4 7X SPECTRUM only The Include option F see Section 3 2 of the HP4T Programmer s Manual is now available on the ZX SPECTRUM version of If you wish to use this option then the source text that is to be subsequently included must be dumped out using a new editor command the W command SPECTRUM only works exactly like P except that it does not dump out in HP4T standard tape format and it begins to save the text to tape immediately the command line is terminated thus you must have the tape recorder in RECORD mode before typing ENTER at the end of the command line When dumping text out using W or reading text in using the F compiler option then you may use the BREAK key at any time the use of this key will return you to the editor Note that if you wish to read in text from the editor via the editor s G command then the text must have been dumped out using P and not Example of use To write out a section of a program use W50 120 PLOT write out the PLOT procedure To include the section in another program 100 END 110 120 F PLOT include the PLOT procedure here 130 140 PROCEDURE MORE rest of 150 HiSoft hope that the above improvements and correction will enhance the use of
52. ed to the storage device Thus you must reload the compiler after a translation if you wish to compile some more text however this is not the usual practice since you will only save complete and tested object code To translate the object code to cassette use the command as specified in Section 4 2 5 of the HiSoft Pascal Programmer s Manual To reload the object code from tape simply use LOAD CODE and then to execute it use RANDOMIZE USR 24608 To translate the object code to Microdrive use the same T command as in Section 4 2 5 but put a Microdrive number and a colon at the front of the filename e g T1 9999 1 OBJ The run times and object will then be stored on the relevant Microdrive as a CODE file To reload this file from within BASIC simply use LOAD M 1 OBJ CODE and then execute it by RAMDOMIZE USR 24608 11 psepuejs 0 Ajesoja 5 48 Iduio2 25 4 2 2861 9 d nj48wod pue jseJ S b TVOSVd LIOSIH PASCAL HiSoft Pascal The Pascal Compiler for your ZX Spectrum More High Quality Software for the ZX Spectrum E HiSoft Software HiSoft HiSoft The Old School Greenfield Bedford MK45 5DE UK Tel 0525 718181 Fax 0525 713716 HiSoft Pascal for the ZX Spectrum Pascal is a full featured fast easy to use and standard implementation of the Pascal prog
53. eful if you wish to read a component of type character at the beginning of a program but it is not necessary if you are reading an integer or a real since end of line markers are skipped or if you are reading characters from subsequent lines 2 3 2 Input Functions 2 3 2 1 EOLN The function EOLN is a Boolean function which returns the value TRUE if the next char to be read would be an end of line character chr 13 Otherwise the function returns the value FALSE 2 3 2 2 INCH The function INCH causes the keyboard of the computer to be scanned and if a key has been pressed returns the character represented by the key pressed If no key has been pressed then CHR 0 is returned The function therefore returns a result of type character 2 3 3 Transfer Functions 2 3 3 1 TRUNC X The parameter X must be of type real or integer and the value returned by TRUNC is the greatest integer less than or equal to X if X is positive or the least integer greater than or equal to X if X is negative Examples TRUNC 1 5 returns 1 TRUNC 1 9 returns 1 2 3 3 2 ROUND X X must be of type real or integer and the function returns nearest integer to X according to standard rounding rules Examples ROUNDY 6 5 returns 6 ROUND 6 51 returns 7 ROUND 11 7 returns 12 ROUND 23 5 returns 24 2 3 3 3 ENTIER X X must be of type real or integer ENTIER returns the greatest integer less than or equal to X for all X Examples
54. elf One feature that has been added is related to the action taken when a breakpoint is encountered Previously when a breakpoint was found a break was made immediately to the Front Pane display in Version 3 2M when a breakpoint is found a short tone is sounded through the SPECTRUM S loudspeaker and execution pauses waiting for you to hit any key when you hit a key the Front Panel display is entered Also itis now not necessary to have the same value in the Memory Pointer and the Program Counter when single stepping The extra features available in GENS3M2 compared with GENS3 are as follows The Editor P and B commands These commands remain identical for P utting or G etting text to and from cassette tape but have been modified so that if the first 2 characters of the filename consist of a digit 1 8 inclusive followed by a colon then the text will be stored to or retrieved from the relevant Microdrive Thus to store lines 10 to 190 of a text file to Microdrive 1 you simply use P1 190 1 TEST and the text file will be stored on Microdrive 1 with the name TEST Note that when P utting if the file already exists then you will be asked File Exists Delete Y N answer Y to delete the file and continue or any other key to return to the editor without deleting the file If when G etting the file does not exist then the message Absent is displayed You must specify a filename if you wish to G et a fi
55. g is found Note that the text pointer is always positioned at the start of the line after a successful search S substitute the previously defined substitute string for the currently found occurrence of the find string and then perform the sub command F i e Search for the next occurrence of the find string This together with the above F sub command is used to step through the text file optionally replacing occurrences of the find string with the substitute string see Section 4 3 for an example 4 Important 5 Note In the current version of HP4T there is a known bug the operation of the sub command S this sub command should only be used immediately after an F command an F sub command or S sub command In practice this should pose no problems insert characters at the current pointer position You will remain in this sub mode until you press RETURN this will return you to the main Edit mode with the pointer positioned after the last character that you inserted Using DELETE or BACKSPACE within this sub mode will cause the character to the left of the pointer to be deleted from the buffer while the use of Cl control function will advance the pointer to the next tab position inserting spaces X this advances the pointer to the end of the line and automatically enters the insert sub mode detailed above C change sub mode This allows you to overwrite the character at the current pointer
56. he full width of 12 characters will always be output If gt 8 then one or more decimal places will be output up to a maximum of 5 decimal places 12 For gt 12 leading spaces are inserted before the number Examples WRITE 1 23E 10 m 7 gives 1 23000E 10 m 8 gives 1 2E 10 m 9 gives 1 23E 10 m 10 gives 1 230E 10 m 11 gives 1 2300E 10 m 12 gives 1 23000E 10 m 13 gives _ 1 23000E 10 If the form e m n is used then a fixed point representation of the number e will be written with n specifying the number of decimal places to be output No leading spaces will be output unless the field width m is sufficiently large If n is zero then e is output as an integer If e is too large to be output in the specified field width then it is output in scientific format with a field width of m see above Examples WRITE 1E2 6 2 gives 100 00 WRITE 1E2 8 2 gives 100 00 WRITE 23 455 6 1 gives 23 5 WRITE 23 455 4 2 gives _2 34550E 01 WRITE 23 455 4 0 gives 23 4 e is of type character or type string Either lt e gt or lt e m gt may be used and the character or string of characters will be output in a minimum field width of 1 for characters or the length of the string for string types Leading spaces are inserted for m is sufficiently large 5 e is of type Boolean Either e or lt e m gt may be used and TRUE or FALSE will be output depending on the Boolean value of e using a minimum field
57. ic variable itself is accessed by including a after the pointer variable Examples of the use of pointer types can be studied in Appendix 4 There are some restrictions on the use of pointers within HiSoft Pascal 4 These are as follows Pointers to types that have not been declared are not allowed This does not prevent the construction of linked list structures since type definitions may contain pointers to themselves e g TYPE item RECORD value INTEGER next item END link item Pointers to pointers are not allowed Pointers to the same type are regarded as equivalent e g VAR first link current item The variables first and current are equivalent i e structural equivalence is used and may be assigned to each other or compared The predefined constant NIL is supported and when this is assigned to a pointer variable then the pointer variable is deemed to contain no address 1 7 4 RECORDs The implementation of RECORDS structured variables composed of a fixed number of constituents called fields within HiSoft Pascal 4 is as Standard Pascal except that the variant part of the field list is not supported Two RECORD types are only treated as equivalent if their declaration stems from the same occurrence of the reserved word RECORD see Section 1 7 1 above The WITH statement may be used to access the different fields within a record in a more compact form See Appendix 4 for an example of the use of WITH and
58. ied with all versions of HiSoft Pascal 4T is a simple line based editor designed to work with all Z80 operating systems while maintaining ease of use and the ability to edit programs quickly and efficiently Text is held in memory in a compacted form the number of leading spaces in a line is held as one character at the beginning of the line and all HPAT Reserved Words are tokenised into one character This leads to a typical reduction in text size of 25 NOTE throughout this section the DELETE key is referred to instead of the control code CH It appears more natural to do this The editor is entered automatically when HP4T is loaded from tape and displays the message Copyright HiSoft 1982 All rights reserved followed by the editor prompt gt In response to the prompt you may enter a command line of the following format N2 51 52 followed by a RETURN where C is the command to be executed see Section 4 2 below N1 is a number in the range 1 32767 inclusive N2 is a number in the range 1 32767 inclusive 51 is a string of characters with a maximum length of 20 S2 is a string of characters with a maximum length of 20 The comma is used to separate the various arguments although this be changed see the S command and spaces are ignored except within the strings None of the arguments are mandatory although some of the commands e g the D elete command will not proceed without 1 and 2 being spec
59. ified The editor remembers the previous numbers and strings that you entered and uses these former values where applicable if you do not specify a particular argument within the command line The values of N1 and N2 are initially set to 10 and the strings are initially empty If you enter an illegal command line such as F 1 100 HELLO then the line will be ignored and the message Pardon displayed you should then retype the line correctly e g F1 100 HELLO This error message will also be displayed if the length of S2 exceeds 20 if the length of S1 is greater than 20 then any excess characters are ignored Commands may be entered in upper or lower case While entering a command line all the relevant control functions described in Section 0 0 may be used e g CX to delete to the beginning of the line This lists the current text to the display device from line number n to line number m inclusive The default value for n is always 1 and the default value for m is always 32767 i e default values are not taken from previously entered arguments To list the entire text file simply use L without any arguments Screen lines are formatted with a left hand margin so that the line number is clearly displayed The number of screen lines listed on the display device may be controlled through use of the K command after listing a certain number of lines the list will pause if not yet at line number m hit control function CC to return to the main editor lo
60. ime a Global variables declared in the main program block b Local variables declared in an inner block c Parameters and passed to and from procedures and returned values functions These individual cases are discussed below and an example of how to use this information may be found in Appendix 4 Global variables Global variables are allocated from the top of the runtime stack downwards e g if the runtime stack is at 8000 and the main program variables are i INTEGER ch CHAR x REAL then i which occupies 2 bytes see the previous section will be stored at locations B000 2 and B000 1 at and AFFF ch 1 byte will be stored at location AFFE 1 i e at AFFD X 4 bytes will be placed at AFF9 AFFA AFFB and AFFC Local variables Local variables cannot be accessed via the stack very easily so instead the IX register is set up at the beginning of each inner block so that 4 points to the start of the block s local variables e g PROCEDURE test VAR INTEGER then i integer so 2 bytes will be placed at IX 4 2 and IX 4 1 i e IX 6 and IX 5 j will be placed at IX 8 and 7 Parameters and returned values Values parameters are treated like local variables and like these variables the earlier parameter is declared the higher address it has in memory However unlike variables the lowest not the highest address is fixed and this is fixed at
61. ing is required 1 7 1 ARRAYs SETs The base type of a set may have up to 256 elements This enables SETs of CHAR to be declared together with SETs of any user enumerated type Note however that only sub ranges of integers can be used as base types All subsets of integers are treated as sets of 0 255 Full arrays of arrays arrays of sets records of sets etc are supported Two ARRAY types are only treated as equivalent if their definition stems from the same use of the reserved word ARRAY Thus the following types are not equivalent TYPE tablea ARRAY 1 100 OF INTEGER tableb ARRAY 1 100 OF INTEGER So a variable of type tablea may not be assigned to a variable of type tableb This enables mistakes to be detected such as assigning two tables representing different data The above restriction does not hold for the special case of arrays of a string type since arrays of this type are always used to represent similar data 1 7 2 Pointers HiSoft Pascal 4 allows the creation of dynamic variables through the use of the Standard Procedure NEW see Section 2 A dynamic variable unlike a static variable which has memory space allocated for it throughout the block in which it is declared cannot be referenced directly through an identifier since it does not have an identifier instead a pointer variable is used This pointer variable which is a static variable contains the address of the dynamic variable and the dynam
62. itten or m is not present then e is written out in full with a trailing space and m is ignored Note that if m is specified to be the length of e without the trailing space then no trailing space will be output 2 e is of type integer and the form lt e m H gt is used In this case e is output in hexadecimal If m 1 or m 2 then the value MOD 16 m is output in a width of exactly m characters If m 3 or m 4 then the full value of e is output in hexadecimal in a width of 4 characters If m gt 4 then leading spaces are inserted before the full hexadecimal value of e as necessary Leading zeroes will be inserted where applicable Examples WRITE 1025 m H outputs 1 outputs 01 outputs 0401 outputs 0401 outputs 0401 3333 3 Hd 3 e is of type real The forms e lt e m gt or lt e m n gt may be used The value of e is converted to character string representing a real number The format of the representation is determined by n If n is not present then the number is output in scientific notation with a mantissa and an exponent If the number is negative the a minus sign is output prior to the mantissa otherwise a space is output The number is always output to at least one decimal place up to a maximum of 5 decimal places and the exponent is always signed either with a plus or minus sign This means that the minimum width of the scientific representation is 8 characters if the field width m is less than 8 then t
63. le from a Microdrive cartridge you cannot load the first file since there isn t one If you do not have Microdrives attached to your system then you must ensure that the second character of any filename you use is not a colon The Assembler Command F is used to include text from a storage device while assembling In GENS3M5 this command has been extended to allow you to include text from a Microdrive cartridge again the method is simply to include a Microdrive number 1 8 inclusive before the filename On cassette you must use the T editor command to dump out text that you wish to include at a later stage and the use of F automatically turns off all other assembler commands On Microdrive these two restrictions can be relaxed you can include a text file that was stored on cartridge using the F command and all assembler commands are available while including Thus to include the text file TEST see the example above you might have something like this LD AB CALL AOUT Include the file TEST from Microdrive F 1 TEST H Next Routine Note that you must specify a filename when using F with Microdrives and if the Included code contains an error you must continue with the assembly do not try to get back to the editor via E while including text from a Microdrive The Editor O command The O command has been added to allow you to dump out object code directly to cassette tape or microdrive
64. ll extended ASCII character set of 256 elements BOOLEAN TRUE FALSE This type is used in logical operations including the results of comparisons 23 PROCEDURES AND FUNCTIONS 2 3 4 Input and Output Procedures 2 3 1 1 WRITE The procedure WRITE is used to output data to the screen or printer When the expression to be written is simply of type character then WRITE e passes the 8 bit value represented by the value of the expression e to the screen or printer as appropriate Note CHR 8 CTRL H gives a destructive backspace on the screen CHR 12 CTRL L clears the screen or gives a new page on the printer CHR 13 CTRL M performs a carriage return and line feed CHR 16 CTRL P will normally direct output to the printer if the screen is in use or vice versa Generally though WRITE P1 P2 Pn is equivalent to BEGIN WRITE P1 WRITE P2 WRITE Pn END The write parameters P1 P2 Pn can have one of the following forms e or e m or lt e m n gt or lt e m H gt where e m and n are expressions and H is a literal constant We have 5 cases to examine 1 is of type integer and either e or lt e m gt is used The value of the integer expression e is converted to a character string with a trailing space The length of the string can be increased with leading spaces by the use of m which specifies the total number of characters to be output If m is not sufficient for e to be wr
65. meter is a variable parameter 25 BEGIN expected 26 Variable expected in call to READ 27 Cannot compare expression of this type 28 Should be either type INTEGER or REAL 29 Cannot read this type of variable 30 This identifier is not a type 31 Exponent expected in real number 32 Scalar expression not numeric expected 33 Null strings not allowed use CHR 0 34 expected 35 expected 36 Array index type must be scalar 37 expected 38 or expected in ARRAY declaration 39 Lower bound greater than upper bound 40 Set too large more than 256 possible elements 41 Function result must be type identifier 42 or expected in set 43 or expected in set 44 Type of parameter must be a type identifier 45 Null set cannot be the first factor in a non assignment statement 46 Scalar including real expected 47 Scalar not including real expected 48 Sets incompatible 49 lt and gt cannot be used to compare sets 50 FORWARD LABEL CONST VAR TYPE or BEGIN expected 51 Hexadecimal digit expected 52 Cannot POKE sets 53 Array too large gt 6 0o004o0oN2 54 END or expected in RECORD definition 55 Field identifier expected 56 Variable expected after WITH 57 Variable in WITH must be of RECORD type 58 Field identifier has not had associated WITH statement 59 Unsigned integer expected after
66. n the first HP4T file on the tape will be loaded regardless of its file name While searching of the tape is going on you may abort the load by holding CC down this will interrupt the load and return to the main editor loop Note that if any text file is already present then the text file that is loaded from tape will be appended to the existing file and the whole file will be renumbered starting with line 1 in steps of 1 Command W n m s the HP4S Spectrum version only The line range n x m is saved to tape under the file name specified by the string s in a format which can be loaded with the compiler option F inclusion of Pascal source text Before entering this command make sure that your tape recorder is switched on and is in RECORD mode 4 2 5 Compiling and Running from the Editor Command C n This causes the text starting at line number n to be compiled If you do not specify a line number then the text will be compiled from the first existing line For further details see Section 0 2 Command R The previously compiled object code will be executed but only if the source has not been expanded in the meantime see Section 0 2 for more detail Command This is the T ranslate command The current source is compiled from line or from the start if n is omitted and if the compilation is successful you will be prompted with if you answer to this prompt then the object code produced by
67. no stack checks are performed DEFAULT 5 Option A Controls whether checks are made to ensure that array indices are within the bounds specified in the array s declaration If A and an array index is too high or too low then the message Index too high or Index too low will be displayed and the program execution halted If A then no such checks are made DEFAULT Option I When using 16 bit 2 s complement integer arithmetic overflow when performing a gt lt gt or lt operation if the arguments differ by more than MAXINT 32767 If this occurs then the result of the comparison will be incorrect This will not normally present any difficulties however should the user wish to compare such numbers the use of I ensures that the results of the comparison will be correct The equivalent situation may arise with real arithmetic in which case an overflow error will be issued if the arguments differ by more than approximately 3 4E38 this cannot be avoided If l then no check for the result of the above comparisons is made DEFAULT I Option P If the P option is used the device to which the compilation listing is sent is changed i e if the video screen was being used the printer is used and vice versa Note that this option is not followed by or DEFAULT The video screen is used Option F This option letter must be followed by a space and then eight character file name If the file name ha
68. oad from tape data which has been recorded in format Thus to load the compiler and run times from the master tape supplied by HiSoft the user must first load the loader when applicable this is supplied in a form suitable for loading by the user s operating system If the user is unable to access the computer s operating system then the boot loader must be entered into the computer s memory directly either through the use of an assembler or a high level language such as BASIC details of how to do this and a skeletal loader appear in the Alteration Guide Once the loader has been executed it will proceed to search for a file recorded in tape format When a file of this format has been found the loader will load the file into memory If at any stage an error is detected while reading the tape a message will be displayed you must then rewind the tape to the beginning of the file and attempt to load it again If you experience repeated errors then adjust the volume level on your tape recorder if this is not successful then please return the tape to HiSoft and we will send you a replacement tape Thus the loader will automatically load the compiler and run times into memory for you When the compiler has been successfully loaded it will execute automatically and produce the message Top of RAM You should respond to this by either entering a positive decimal number up to 65536 followed by RETURN or by hitting RETU
69. op or any other key to continue the listing Command Kn K sets the number of screen lines to be listed to the display device before the display is paused as described in L above The value n MOD 256 is computed and stored For example use K5 if you wish a subsequent L ist to produce five screen lines at a time 4 2 3 Text Editing Once some text has been created there will inevitably be a need to edit some lines Various commands are provided to enable lines to be amended deleted moved and renumbered Command D n m All lines from n to m inclusive are deleted from the text file If m n or less than two arguments are specified then no action will be taken this is to help prevent careless mistakes A single line may be deleted by making mzn this can also be accomplished by simply typing the line number followed by RETURN Command M n m This causes the text at line n to be entered at line m deleting any text that already exists there Note that line n is left alone So this command allows you to M ove a line of text to another position within the text file If line number n does not exists then no action is taken Command N n m Use of the N command causes the text file to be renumbered with a first line number of n and in line number steps of m Both n and m must be present and if the renumbering would cause any line number to exceed 32767 then the original numbering is retained Command F n m f s
70. or F and G commands These commands remain identical For P utting or G etting text to and from cassette tape but have been modified so that if the first 2 characters of the filename consist of a digit 1 0 inclusive followed by a colon then the text will be stored to or retrieved from the relevant Microdrive Thus to store lines 10 to 190 of a text file to Microdrive 1 you simply use P10 190 1 TEST and the text file will be stored on Microdrive1 with the name TEST Note that when P utting if the file already exists then it is automatically deleted whereas if when G etting the file does not exist then the message Absent is displayed You must specify a filename if you wish to G et a file from a Microdrive cartridge you cannot land the first file since there isn t one If you do not have Microdrives attached to your system then you must ensure that the second character of any filename you use is not a colon The F Compiler Option While compiling you may include a text file from either cassette tape or from a Microdrive by using the F compiler option The format of this option when used to compile a file from cassette tape is explained in Section 3 of the HiSoft Pascal Programmer s Manual When used with Microdrives the only difference is that the first two characters of the filename should be a Microdrive number 1 8 inclusive followed by a colon Thus to include the file TEST stored to Microdriv
71. ou do not wish to use this editor but want to interface your own editor then you should consult the HP4T Alteration Guide The above Sections should be read carefully by all users Appendix 1 details the error messages generated both by the compiler and the run times Appendix 2 lists the predefined identifiers and reserved words Appendix 3 gives details on the internal representation of data within HiSoft Pascal 4 useful for programmers who wish to get their hands dirty Appendix 4 gives some example Pascal programs study this if you experience any problems in writing HiSoft Pascal 4 programs 0 2 Compiling and Running For details of how to create amend compile and run an program using the integral line editor see Section 4 of this manual For information on what to do if you are using your own editor see the Alteration Guide Once it has been invoked the compiler generates a listing of the form xxxx nnnn text of source line where is the address where the code generated by this line begins nnnn is the line number with leading zeroes suppressed If a line contains more than 80 characters then the compiler inserts new line characters so that the length of a line is never more than 80 characters The listing may be directed to a printer if required by the use of option P if supported see Section 3 You may pause the listing at any stage by pressing CS subsequently use CC to return to the e
72. r whole numbers are treated as reals The mantissa of reals is 23 bits in length The accuracy attained is therefore about 7 significant figures Note that accuracy is lost if the result of a calculation is much less than the absolute values of its argument e g 2 00002 2 does not yield 0 00002 This is due to the inaccuracy involved in representing decimal fractions as binary fractions It does not occur when integers of moderate size are represented as reals e g 200002 200000 2 exactly The largest real available is 3 4E38 while the smallest is 5 9E 39 There is no point in using more than 7 digits in the mantissa when specifying reals since extra digits ignored except for their place value When accuracy is important avoid leading zeroes since these count as one of the digits Thus 0 000123456 is represented less accurately than 1 23456E 4 Hexadecimal numbers are available for programmers to specify memory addresses for assembly language linkage inter alia Note that there must be at least one hexadecimal digit present after the otherwise an error 51 will be generated 1 4 UNSIGNED CONSTANT Note that strings may not contain more than 255 characters String types are ARRAY 1 N OF CHAR where N is an integer between 1 and 255 inclusive Literal strings should not contain end of line characters CHR 13 if they do then an ERROR 68 is generated The characters available are the full expanded
73. ramming language Key features the powerful control structures of Pascal CASE REPEAT UNTIL IF THEN ELSE WHILE DO etc Full range of data structures including records sets arrays pointers integer and floating point arithmetic Proceduresand functions may be fully recursive with value and variable param Compiles at very high speed and generates phenomenally fast code which can be executed independently Full support of the Spectrum including Logo style Turtle Graphics for easy production of graphic displays Uses only 20K of memory allowing large programs to be created especially if the source is compiled from lape disk Integrated editor with optional 1 column mode Easy interface with the Spectrum s ROM through the use of PEEK POKE USER and INLINE HiSoft Pascal has been developed over many years and is highly tuned and stable product is equally ideal for the student who wishes to supplement his her coursework at home the professional programmer who can produce commercial programs with the package and in fct anyone who wants to learn or use this very popular structured programming language HiSoft Pascal requires AnyZX Spectrum computer Special 3 version isavailable A tape recorder microdrive or Disciple Opus disk system This package contains page manual detailing every aspect of the HiSoft Pascal implementation including many example programs
74. s The result is always of type real 2 3 4 6 COS X Returns the cosine of X where X is in radians The result is of type real 2 3 4 7 TAN X Returns the tangent of X where X is in radians The result is always of type real 2 3 4 8 ARCTAN X Returns the angle in radians whose tangent is equal to the number X The result is of type real 2 3 4 9 EXP X Returns the value e X where e 2 71828 The result is always of type real 2 3 4 10 LN X Returns the natural logarithm i e to the base e of X The result is of type real If X lt 0 then a Maths Call Error will be generated 2 3 5 Further Predefined Procedures 2 3 5 1 NEW p The procedure NEW p allocates space for a dynamic variable The variable p is a pointer variable and after NEW p has been executed p contains the address of the newly allocated dynamic variable The type of the dynamic variable is the same as the type of the pointer variable p and this can be of any type To access the dynamic variable p is used see Appendix 4 for an example of the use of pointers to reference dynamic variables To re allocate space used for dynamic variables use the procedures MARK and RELEASE see below 2 3 5 2 MARK v1 This procedure saves the state of the dynamic variable heap to be saved in the pointer variable v1 The state of the heap may be restored to that when the procedure MARK was executed by using the procedure RELEASE see below The type of variable to whi
75. s less than eight characters it should be padded with spaces The presence of this option causes inclusion of Pascal source text from the specified file from the end of the current line useful if the programmer wishes to build up a of much used procedures and functions on tape and then include them in particular programs The program should be saved using the built in editor s command On most systems the list option L should be used otherwise the compiler will not compile fast enough Example L F MATRIX include the text from a tape file MATRIX When writing very large programs there may not be enough room in the computer s memory for the source and object code to be present at the same time It is however possible to compile such programs by saving them to tape and using the F option then only 128 bytes of the source are in RAM at any one time leaving much more room for the object code This option may not be nested and is not implemented in the ZX Spectrum version the HP4S ZX Spectrum version this option is implemented The Pascal source text which is to be included should be saved using the built in editor s command instead of P The compiler options may be used selectively Thus debugged sections of code may be speeded up and compacted by turning the relevant checks off whilst retaining checks on untested pieces of code 4 THE INTEGRAL EDITOR 4 1 Introduction to the Editor The editor suppl
76. s are included to reflect the changing environment in which compilers are used among these are POKE PEEK TIN TOUT and ADDR The compiler occupies approximately 12K of storage while the run times take up roughly 4K Both are supplied on cassette tape in the tape format used by the run times All interfacing between and the host machine takes place through vectors conveniently placed at the start of the run times see Alteration Guide this makes it easy for the user to write his own customised I O routines if necessary HiSoft Pascal 4T uses various control codes mostly within the editor Of course different systems can have very different keyboard designs and thus will have different ways of reaching control codes In this manual the control characters used will be refereed to as RETURN CC CH CI CP CS and CX The attached Implementation Note will tell you the corresponding keys for your system Whenever is waiting for a line of input the control characters can be used as follows RETURN is used to terminate the line CC returns to the editor CAPS SHIFT 1 CH deletes the last character typed CAPS SHIFT 0 CI move to the next TAB position CAPS SHIFT 8 CP directs output to the printer if available or if output was going to the printer then it returns to the screen WRITE CHR 16 CX deletes the whole line typed so far CAPS SHIFT 5 A simple loader is also supplied in the package so that the user can l
77. t Pascal 4D and HiSoft Pascal 4T is now 1 4 effective from October 1982 The differences between the previous version of HiSoft Pascal and version 1 4 are given below 1 A bug the evaluation of expressions which led to expressions like 1 SQR 2 being incorrectly evaluated has been corrected 2 A bug in the evaluation of expressions which led to expressions like 1 1 1 being incorrectly evaluated has been corrected 3 A bug that caused the incorrect evaluation of the result of an integer to real comparison has been corrected 4 HiSoft Pascal 4T only the documented bug in the editor S see page 38 of the Programmer s Manual has been corrected S can now be used at any time 5 HiSoft Pascal 4T only using the F command from within the editor to find a character string now positions the editing cursor at the beginning of any found occurrence of the string of pages 37 and 38 of the Programmer s Manual 6 HiSoft Pascal 4T only a new editor command has been incorporated The X command displays in hexadecimal the current end address of the compiler This information allows the user to make a working copy of the compiler and thus minimizes the danger of corrupting the master tape Note that you are authorised by HiSoft to make only one working copy of HP4T To make a working copy first find the start address of the package from your Implementation Note and then find the end address using
78. t ways of ensuring that the user does not use an element of data in a manner which is inconsistent with its definition At the one end of the scale there is machine code where no checks whatever are made on the TYPE of variable being referenced Next we have a language like the Byte Pascal in which character integer and Boolean data may be freely mixed without generating errors Further up the scale comes which distinguishes between numbers and strings and sometimes between integers and reals perhaps using the sign to denote integers Then comes Pascal which goes as far as allowing distinct user enumerated types At the top of the scale at present is a language like ADA in which one can define different incompatible numeric types There are basically two approaches used by Pascal implementations to strength of typing structural equivalence or name equivalence HiSoft Pascal 4 uses name equivalence for RECORDs and ARRAYs The consequences of this are clarified in Section 1 let suffice to give an example here say two variables are defined as follows VAR A ARRAY A C JOF INTEGER B ARRAY C JOF INTEGER then one might be tempted to think that one could write A B but this would generate an error 10 under HiSoft Pascal 4 since two separate TYPE records have been created by the above definitions In other words the user has not taken the decision that A and B should represent the same type of data
79. tly using MONS3M2 or POKE within BASIC or use GENS3M2 or another assembler heaven forbid to assemble the source of the program Note that the program is currently positioned at location 60000 you may of course change this if you re assemble Once the code is in the computer you may execute from within BASIC or patch it into the editor in GENS3M2 To use it from BASIC first POKE the Microdrive number you with to catalog into location 60345 assuming the code starts at 60000 and then use RANDOMIZE USR 60000 To use the code from within GENS3M2 you must patch the dummy Z command to jump to the CATalogue code To do this patch load up GENS3M2 and then POKE the address of the extended CATalogue routine 2 into locations Start of GENS3M2 7790 and Start of 5 7791 low order byte first For example say you have loaded GENS3M2 at 26000 and the extended CATalgue routine is at 60000 Then to effect the patch simply do POKE 33790 98 and POKE 33791 234 and then enter GENS3H2 in the normal way You can now use 2n from within the editor to CATalogue drive number n Below it the lifting of the extended CATalogue programs Microdrive Extended CATalogue 1 Microdrive Extended CATalogue 2 Hisoft GEN Assembler 28 February 1704 Produced with Hisoft s BEN assenbl Copyright Hisoft 1904 6 yWith many thanks to Andrew Pennell for his 7 pMicrodrive bible and the Gtream 14 routine 50 BENS3M2 entry point
80. when a variable is declared then it may be followed optionally by constant with a value between 1 and 255 inclusive enclosed in square brackets This constant specifies the buffer size used for this file in 128 character units For example if you require the file file1 to have a buffer size of 2K 2048 characters then the declaration should look like VAR file1 FILE OF CHAR 16 or CONST filesize 16 VAR file1 TEXT filesize Forward References As in the Pascal User Manual and Report Section 11 C 1 procedures and functions may be referenced before they are declared through use of the Reserved Word FORWARD e g PROCEDURE a y t FORWARD procedure a declared to PROCEDURE b x t forward of this statement BEGIN a p procedure a referenced END PROCEDURE a actual declaration of procedure a BEGIN END Note that the parameters and result type of the procedure a are declared along with FORWARD and are not repeated in the main declaration of the procedure Remember FORWARD is a Reserved Word 1 17 PROGRAM PROGRAM gt identifier gt gt block END gt Since files are not implemented there are no formal parameters of the program 2 PREDEFINED IDENTIFIERS 2 1 CONSTANTS MAXINT The largest integer available i e 32767 TRUE FALSE The constants of type Boolean 22 TYPES INTEGER See Section 1 3 REAL See Section 1 3 CHAR The fu
81. width of 4 or 5 respectively 2 3 1 2 WRITELN WRITELN output gives a newline This is equivalent to WRITE CHR 13 Note that a linefeed is included WRITELN P1 P2 P3 is equivalent to BEGIN WRITE P1 P2 P3 WRITELN END 2 3 1 The procedure PAGE is equivalent to WRITE CHR 12 and causes the video screen to be cleared or the printer to advance to the top of a new page 2 3 1 4 READ The procedure READ is used to access data from the keyboard It does this through a buffer held within the run times this buffer is initially empty except for an end of line marker We can consider that any accesses to this buffer take place through a text window over the buffer through which we can see one character at a time If this text window is positioned over an end of line marker then before the read operation is terminated a new line of text will be read into the buffer from the keyboard While reading in this line all various control codes detailed in Section 0 0 will be recognised Now READ V1 V2 Vn is equivalent to BEGIN READ V1 READ V2 READ Vn END where V1 V2 etc may be of type character string integer or real The statement READ V has different effects depending on the type of V There are 4 cases to consider 1 V is of type character In this case READ V simply reads a character from the input buffer and assigns it to V If the text window on the buffer is positioned on a

Untitled - sinclair

Contents

Download Pdf Manuals

Related Search

Related Contents