PBCC: PicoBlaze C Compiler User Manual
Contents
1. CL PicoBlaze C Compiler 2010 03 31 Virtu ln laborato aplikace mikroprocesorov techniky U ser M anua l Revision 2 Virtual Laboratory of Microprocessor Technology Application PBCC PicoBlaze C Compiler User Manual Zbyn k K ivka krivka fit vutbr cz Report for Virtual Laboratory of Microprocessor Technology Application 2C06008 supported by MSMT 2008 2010 Zbyn k K ivka http www vlam cz UNIS spol s r o R amp D UTIA CAS CR VUT Brno FIT DIFS Obs PicoBlaze C Compiler PBCC 2009 03 31 Virtu ln laborato aplikace mikroprocesorov techniky U S e r M a n u al R evi S i on 2 Virtual Laboratory of Microprocessor Technology Application Content Terminoloty HH PH 3 TEU ig osea ON vun Eit E iM tu erect E Mid ENDE RE M ENS 4 ZAPONOG TG assener date Anm ERAS ADR E o E a M MK k One osumn ct aE 4 SDCC Front end T vad adKsb 4 5 PBCC Backend sse o ssstcon kab Midi p Nn AS naan gas can ES 5 PBECC LI Sab Bosse vba eta Soca asec E E des IM oo UR M 5 Compiling cum c M 5 Command line DAEGIDEISES cocotte IE E Doubs dde adele ea atl Sue DER ony 6 PBCC Commoand Dne Parameters uota a Sicca rui DEN M ees toca dice ES 6 EXamMpl S k n ooo 7 viU uror DS isese 7 Binary Image and VHDL P M 8 PBCC Compilation from Source C OU Dr bronce i btt daga ts ecde eau i2. ln laborato aplikace mikroprocesorov techniky R evision 2 Virtual Laboratory of Microprocessor Technology Application USHRT MAX min value of unsigned short 465 535 465 535 LCD Driver lt ica h gt void LCD init void LCD clear void LCD set cursor macro LCD wr arg void LCD write unsigned char As a part of this driver we introduce subset of functions from Input Output lt stdio h gt Arithmetic Operations Since Xilinx PicoBlaze 3 implements no multiplication or division operation we deal with these operators in a special way For more details see report about the simulation of arithmetic operations in PicoBlaze and the providing support for external operations in Czech Problems and errors Please feel free to contact us main contact krivka fit vutbr cz whenever you find an error or problem please first consult SDCC and PBCC manuals Conclusion Although the project is run only by one person it is already useful to do some basic programming in language C We do not provide all features as old PCCOMP compiler yet we are working on it During 2009 we introduced several optimizations such as register allocation using coloring or analysis of inline assembler During 2010 we upgraded the version of front end to SDCC 3 0 and the back end was completely rewritten in C language as the full featured SDCC port of PicoBlaze 8 bit processor Acknowledgement This work has been supported by the Czech
3. 8924 97 3 7 Ota Jir k Zbyn k K ivka Simulation based Debugging of 8 bit Softcore Processor In Proceedings of XXXIth International Autumn Colloquium Advanced Simulation of Systems Ostrava CZ MARQ 2009 pp 68 73 ISBN 978 80 86840 47 5 2008 2010 Zbyn k K ivka 12 12 http www vlam cz
4. Ministry of Education Youth and Sports grant MSMT 2C06008 Virtual Laboratory of Microprocessor Technology Application visit website http www vlam cz References Xilinx PicoBlaze Product Brief Online Visited 2008 11 13 http www xilinx com bvdocs ipcenter data_sheet picoblaze_productbrief pdf 2 Xilinx PicoBlaze 8 bit Embedded Microcontroller User Guide for Spartan 3 Spartan 6 Virtex 5 and Virtex 6 FPGAs UG129 v2 0 January 28 2010 Online Visited 2010 01 30 http www xilinx com support documentation ip_documentation ug129 pdf 3 Mediatronix pBlazeIDE version 3 74 Beta Online Visited 2008 11 13 http www mediatronix com pBlazeIDE htm 4 Andrew W Appel and Jens Palsberg Modern Compiler Implementation in Java Second Edition Cambridge University Press 2002 501 p ISBN 0 5218 2060 X 5 SDCC Compiler User Guide SDCC 3 0 1 Revision 6041 2010 Online Visited 2010 03 31 http sdcc sourceforge net doc sdccman pdf 2008 2010 Zbyn k K ivka 11 12 http www vlam cz Oeil PicoBlaze C Compiler PBCC 2009 03 31 Virtu ln laborato aplikace mikroprocesorov techniky U S e r M a n u al R evision 2 Virtual Laboratory of Microprocessor Technology Application 6 Ota Jir k Zbyn k K ivka Design and Implementation of Back end for PicoBlaze C Compiler In Proceedings of the IADIS International Conference Applied Computing 2009 Rome IT IADIS Press 2009 pp 135 138 ISBN 978 972
5. cycle based hardware debugging ModelSim Retargetability According to developed methodology we introduced few user defined retargetability options mTARGET PORT NAME from SDCC and dialect arguments For more details see Czech documentation of SDCC and PBCC implementation KCPSMS versus pBlazelDE Assembler Both dialects can be generated by PBCC For more details see PicoBlaze 3 Manual 2 page 69 or pBlazeIDE web page http www mediatronix com Directives htm 2008 2010 Zbyn k K ivka 9 12 http www vlam cz Virtu ln laborato aplikace mikroprocesorov techniky Virtual Laboratory of Microprocessor Technology Application Function Libraries PicoBlaze C Compiler PBCC User Manual 2009 03 31 Revision 2 We have chosen a minimalistic subset of standard C library to support some basic functions such as character class tests lt ctype h gt time and date function lt time h gt basic mathematical functions math h and some utility functions lt stdlib h gt We also make an abstraction of few processor specific features low level functions such as communication with ports enable disable etc Low level functions Processor Interrupt lt intr h gt INPUT OUTPUT handling the interrupts void pbcc set interrupt handler void void void pbcc set interrupt bool enable void pbcc enable interrupt void pbcc disable interrupt BOOL pbcc enabled interrupt Input Outpu
6. together with VHDL Verilog templates compiled by KCPSM3 Assembler into the resulting hardware description of PicoBlaze processor containing the program hard coded in its memory Finally the hardware description can be interconnected with the rest of the embedded system such as external operations implementation synthesized to a bit stream and downloaded into an FPGA chip for instance using Xilinx ISE Webpack PBCC Usage Primarily PBCCv2 is designed as a command line tool that can participate as a component of entire compilation system The included batch files support Windows platform at the moment We plan also to support the Unix based platforms as the background tools and codes are multiplatform supporting both Microsoft Windows and Linux Compiling System The tool chain provides the complete compilation service from C source code to the PicoBlaze 3 assembler that can be simulated or to the HEX file that can be downloaded into FPGA 1 The compilation of C source code by SDCC containing PBCCv2 port called pblaze produces PicoBlaze 3 assembly code in the resulting psm file 2 The compilation from PicoBlaze 3 assembly language to HDL description VHDL or Verilog of the processor with the corresponding memory content image KCP SM3 2008 2010 Zbyn k K ivka 5 12 http www vlam cz Oeil PicoBlaze C Compiler PBCC 2009 03 31 User Manual Virtu ln laborato aplikace mikroprocesorov techniky R evision 2 Virtual Laboratory
7. SDCC Front end SDCC framework is an open source C cross compiler written in C developed primarily for 8 bit MCU with several back end implementations for different MCUs Microchip PIC Intel 8051 Motorola HCOS etc In comparison with GCC and SUIF2 SDCC uses low level 3 address intermediate code representation IR called iCodes Moreover for every investigated framework its IR assumes the support of a native data stack The standard C language from 1999 is augmented according to its conventions see C standard compliance in SDCC manual see Chyba Nenalezen zdroj odkaz by some embedded system specific properties and syntax extensions such as embedded assembler code interrupt handler declaration or the specification of variable location and address Some features are added by pragma optimization control For more details about SDCC framework see report SDCC Framework in Czech or official SDCC documentation Chyba Nenalezen zdroj odkaz and website PBCC Back end The back end internal architecture is based on the transformation of IR towards the optimized target code representation based on resource profiling information to handle essential requirements on the memory unassumingness The SDCC s port is named pblaze Further non native operations e g multiplication are either 1 outsourced by external peripherals or 2 simulated by PicoBlaze instruction set memory consuming The resulting assembly code ASM is
8. ai eda 8 Source code policy Per 8 Specific Syntax and Semantic of PBCC a0 cscs scsscecssscsnsasrascsainavansaseavensandevenseoneenetannsvendasveoaseeass 8 C99 Extensions in SDCC Pront Bid vsssissasentanscnvsiedespenuren sdeueanseavtantanutnddeqssavsdsoavstensasantionseneses 9 PECCO Target OGG acca tga cvestasiesnceteenisbhetpuniensaeeaenee pada ious eee 9 Debus SUpport seconds vaca eee crea ato 9 R targetability e c aaia 9 KCPSM3 versus pBlazeIDE Asserblet iieissc ise erret nita ha paye EE pan tho c Ie dok koks va Res 9 PUTT GIR LIDPOPIOS aeeoeia nc In eera erea Ar beu tas eunt E a lan nnd pa doa NE EEEN 10 Loyslevel Purouons sese oboe Ei E caucus E HUI EN opens 10 Mathematical Functions att Bou B aieo tc a Dico Se EN diced QUE PUE duet egeta inu RE 10 Inteser Type Limits 1 981 ts B gt eese uestes t pP desea Re iua DN aO a MR eMEs 10 LC Driver lt Led Rocas DN um Ead Du E EMI MEME 11 Arithmetie BIET IECUR PG IN ERI S 11 Problems and 6rrOfsusgisoetec uicti GacealedescuersGlacelauerreeee ei eaeetas ete neces 11 odii RT ieres tiriko eE E EEE ARTNR REE A E R E 11 Acknowledgement SNR nea EE e EEO EAS AES SENEE E E PP 11 RG LCRON COS T p E E E E O E eee HE 11 2008 2010 Zbyn k K ivka 2 12 http www vlam cz AE PicoBlaze C Compiler PBCC 2009 03 31 User Manual Virtu ln laborato aplikace mikroprocesorov techniky R evision 2 Virtua
9. boratory of Microprocessor Technology Application dialect kcpsm3 pblazeide selects the assembly language dialect for the PicoBlaze 3 target platform as there are some minor differences between the PicoBlaze 3 Assembler for HDL HEX production KCPSM3 and for the simulation pBlazeIDE Default po1azeide verbose Supported by SDCC generates even more detailed reports into log files including detailed comments directly into the resulting assembler with the emphasis on the human readability Default omitted Future plans Command line Parameters NOT SUPPORTED inline asm dialect kcpsm3 pblazeide selects the assembler dialect for the inline assembler in C source code can be different from dialect argument Default po1azeide NOT SUPPORTED parse inline asm commands to the back end to parse and check the validity of inlined assembler in C source code Default omitted NOT SUPPORTED opt 2code memory chooses the target dependent optimization to be focused on the size of the instruction code code or the amount of memory memory Default no such optimizations yet NOT SUPPORTED stackSize 0 64 dynamic sets the maximal size of the simulated data stack The dynamic approach means that it is limited by hardware conditions Default dynamic NOT SUPPORTED 1SR function number DIGIT specifies the number of the interrupts in the interrupt table vector ISR table Default 1 Example Download
10. boratory of Microprocessor Technology Application Introduction Xilinx PicoBlaze version 3 for FPGA Spartan 3 1 is very tiny and simple soft core processor by Xilinx It provides one interrupt small amount of memory and the limited instruction set with the basic arithmetical logic instruction and branching This processor can be programmed in the specific assembler defined by Xilinx More specifically there are two dialects of the assembler for version 3 First official assembler used by VHDL and HEX generator KCPSM3 and the second assembler accepted by pBlazeIDE graphical simulator of this processor see PicoBlaze manual 2 Architecture As there are several compiler frameworks such as GCC clang for LLVM and SUIF2 we use existing C front end that handles target independent optimizations and focuses on back end design implementation and optimization We have chosen to extend Small Device C Compiler SDCC The high level design of PBCC is shown in Figure 1 The SDCC front end starts with SDCPP adopted GCC preprocessor and GNU Bison to make syntax directed translation of C source into IR list of iCodes consisting of 3 address code with additional high level information such as type information As there is no solid interface for a back end implementation so called port in SDCC and the documentation of this part is totally insufficient we executed several experiments to explore SDCC s IR and documented the way of creation o
11. e function declaration denotes a function that can be called by other functions That is we have to deal with auto local variables and recursion properly including the standard work with the data stack By default a function is not reentrant interrupt 1 This keyword denotes the function that works as an interrupt handler PicoBlaze processor supports only one interrupt that is 1 parameter says if RETURNI is DISABLE default behavior or ENABLE use non zero constant Example void interrupt handler void interrupt 1 the handler definition asm X endasm The pair of keywords encloses the inline assembler code processor specific SDCC makes no validation of this code PBCC does not check the syntax yet planned feature and the registers usage including the references to local variables by ID notation data at 1 NOT SUPPORTED YET This keyword denotes the absolute address 1 of the memory location of the program entity such as variable literal and function PBCC Target code See implementation documentation in Czech details of the structure naming conventions data stack simulation etc Debug Support In analogy with the compilation system phases the debugging is performed in three levels 1 The debugging of SDCC Framework Front end and of PicoBlaze port in Eclipse CDT 2 The instruction based software simulation pBlazeIDE of the target code PicoBlaze 3 Assembler 3 and
12. f new port in SDCC 3 0 In the end PicoBlaze C Compiler is composed of several chained command line tools as shown in Figure 1 Bison H based i i Syntax 7 Code Peephole Generator Directed Transla Figure 1 PicoBlaze C Compiler PBCC Architecture composing of front end and back end connected by IR in iCode format For the classical list of compilation phases see 4 Summary of additional compiler features Control flow graph analysis the absence of indirect function calls and small amount of memory allow the generation of full control flow graph and using global optimization algorithms Due to missing native data stack the scratchpad memory is used for the storage of activation records stack frames for static function calls Due to the very low memory capacity only the most essential global types macros variables and functions will be implemented as the torso of standard C library With so 2008 2010 Zbyn k K ivka 4 12 http www vlam cz Oeil PicoBlaze C Compiler PBCC 2009 03 31 Virtu ln laborato aplikace mikroprocesorov techniky U S e r M a n u al R evi S i on 2 Virtual Laboratory of Microprocessor Technology Application small architecture modularity is a useless luxury so also PBCCV2 supports source code level inclusion only no modularity e As there is no application binary interface by the manufacturer and no linkable code is generated a linker tool is not necessary
13. gure disable picl6 port disable picl4 port disable json port disable ds390 port disable ds400 port 4 Edit src SDCCmain c and comment out line amp json port 5 Compile the code by execution of make all 6 Now you test a command bin sdcc exe version 7 To use SDCC compiler see SDCC manual 5 Source code policy As the compiler is still in the rapid development we do not provide the source code of the modification of SDCC GPL license yet but we will do that before the end of the project summer 2011 Specific Syntax and Semantic of PBCC Since SDCC works as a PBCC s front end it analyses standard C99 language see command line arguments to modify the version of the standard processed by SDCC We shortly revise essential changes and updates in SDCC with respect to the C99 We focus on explaining PicoBlaze specific syntax and semantics modifications with respect to SDCC 2008 2010 Zbyn k K ivka 8 12 http www vlam cz Oeil PicoBlaze C Compiler PBCC 2009 03 31 User Manual Virtu ln laborato aplikace mikroprocesorov techniky R evision 2 Virtual Laboratory of Microprocessor Technology Application C99 Extensions in SDCC Front End To accomplish specific reguirements of embedded systems SDCC introduces several new keywords to handle hardware specific problems in high level C language see Chyba Nenalezen zdroj odkaz reentrant NOT SUPPORTED YET This keyword placed behind th
14. l Laboratory of Microprocessor Technology Application Revisions No Date Author Revision description 1 2009 12 30 Z K ivka First draft 2010 03 31 Z K ivka Second draft new SDCC front end version 3 Abstract PicoBlaze 3 is 8 bit soft core processor developed by Xilinx Company used for simple state control application in IP cores in FPGAs This document describes the development and use of its C compiler version 2 In details the implementation covers only basic aspects of language C because of the complexity that cannot be handled in such small processor To deal with the standard syntax and some semantics of C we use framework SDCC 3 0 and higher focused on 8 bit CPUs As this is a user manual it describes the command line interface of new version of the compiler abbrev PBCCv2 or PBCC For more details about the architecture and implementation of PBCC see PicoBlaze C Compiler report in Czech Keywords Compiler parser language C ANSI C 8 bit processor PicoBlaze PBCCv2 KCPSM3 SDCC 3 0 front end back end Terminology IR intermediate internal code representation e g 3 address code IS Instruction set PBCC v2 PicoBlaze C Compiler version 2 SDCC Small Device C Compiler 2008 2010 Zbyn k K ivka 3 12 http www vlam cz Odi PicoBlaze C Compiler PBCC 2009 03 31 User Manual isi Virtu ln laborato aplikace mikroprocesorov techniky R evision 2 Virtual La
15. of Microprocessor Technology Application Now the user can integrate the processor into a new FPGA design using Xilinx Design Tools such as Xilinx ISE or Xilinx EDK or just use it as a new processor code for existing one using for example ODevKit for FITKit demonstration board Command line parameters This section describes the command line parameters of the tools in the PBCC Compilation System First we describe the compilation system based on a batch file ppcc bat Second we describe PBCC specific parameters of SDCC front end Phase 1 In addition we repeat the most useful arguments used by SDCC Third we introduce all supported and planned parameters of PBCCv2 back end In the end we give some tips about the simulation of the resulting PicoBlaze 3 Assembler code and creating FPGA bitstream with the PicoBlaze 3 processor using integrated development tools such as Xilinx ISE Webpack or QDevKit As the PicoBlaze processor is developed by Xilinx Company we are focused on the FPGA chips also from Xilinx The main compilation batch file is pbcc bat with the following usage pbcc bat source c kcpsm3 pblazeide pause The first parameter is the filename of the source code c extension is mandatory to be compiled Next parameter chooses the dialect kcpsm3 is default to generate The last parameter pause enables pauses between each phase of the compilation system for debugging purposes implicitly no pauses To ensure valid
16. paths linking to the required tools modify four environment variables in the batch file paths are relative with respect to the current directory of the batch file SET SDCC_PATH sdcc bin directory of sdcc exe and sdcpp exe SET ASM_PATH KCPSM3 Assembler directory of KCPSM3 exe SET SIMUL_PATH pBlazeIDE directory of pBlazeIDE pBlazIDE exe The result of the compilation chain executed by pbcc bat is the HEX file of the same name as the input C file e g source hex There are created also some temporary files useful for the debugging SSDCC_PATH source psm and ASM_PATH source psm if used kcpsm3 argument PBCC Command line Parameters Now we list the complete list of supported parameters of PBCC back end to generate target code in PBCC compilation system The arguments are case sensitive The syntax of the arguments has to be satisfied carefully otherwise unexpected behavior or error can appear o lt output psm gt Supported by SDCC sets the output filename with the target code PicoBlaze 3 Assembler Default source psm mpblaze chooses the target platform Now only PicoBlaze3 processor is supported by the PBCCv2 port For other target platforms see SDCC manual Mandatory option 2008 2010 Zbyn k K ivka 6 12 http www vlam cz Oeil PicoBlaze C Compiler PBCC 2009 03 31 Virtu ln laborato aplikace mikroprocesorov techniky U S e r M a n u al R evi S i on 2 Virtual La
17. t port port h gt unsigned char port read unsigned char port unsigned short pbcc input short unsigned char port void port write unsigned char port unsigned char cdata void pbcc output short unsigned char port unsigned short sdata Delay lt delay h gt void delay unsigned char c Mathematical Functions lt math h gt Arguments and returned values are decimal types unsigned int pow unsigned int unsigned int unsigned int sqrt unsigned int Integer Type Limits lt limits h gt unsigned int The numbers given in parentheses are values for the PicoBlaze C Compiler for typical 32 bit Unix system CHAR BIT bits in char CHAR MAX max value of char CHAR MIN min value of char INT MAX max value of int INT MIN min value of int LONG MAX max value of long LONG MIN min value of long SCHAR MAx max value of signed char SCHAR MIN min value of signed char SHRT MAX max value of short SHRT MIN min value of short UCHAR MAX max value of unsigned char UINT MAX min value of unsigned int ULONG MAX 2008 2010 Zbyn k K ivka http www vlam cz 8 8 127 127 or 255 128 128 or 0 32 767 32 767 32 768 32 768 2 147 483 647 22 147 483 648 127 127 128 128 32 767 32 167 32 768 32 768 255 255 65 535 65 535 max value of unsigned long 4 294 967 295 4 294 967 295 10 12 Usu PicoBlaze C Compiler PBCC 2009 03 31 User Manual Virtu
18. the 32 bit Windows binary package from the webpage of VLAM project We assume that you preserve the directory structure in the package and you decompress it in the root of system disc C 1 PBCCv2 SDCC compiler execution for more inspiration see pbcc bat C pbcc sdec bin sdec exe c IC pbcc sdcc device include picoBlaze mpicoBlaz all call saves lt program c gt 2 Now you can simulate the PicoBlaze 3 Assembler in pBlazeIDE see section Simulation Tips or continue the translation process by KCPSM3 to get VHDL and HEX files useful to generate bitstream for FPGA see section Binary Image and VHDL Simulation Tips pBlazeIDE pBlazIDE exe see 3 is a simulation environment with the graphical user interface for Microsoft Windows It can simulate several different assembler dialects such as Picoblaze I IL 3 and CR 2008 2010 Zbyn k K ivka 7 12 http www vlam cz Oeil PicoBlaze C Compiler PBCC 2009 03 31 User Manual Virtu ln laborato aplikace mikroprocesorov techniky R evision 2 Virtual Laboratory of Microprocessor Technology Application To simulate the dialect pblazeide produced by PBCC execute the GUI of the simulator check menu Settings that item PicoBlaze 3 is selected Now we can import the generated assembler file psm by menu File Import to satisfy the specific syntax requirements of pBlazeIDE Warning As the import includes some text instructions processing do not use menu File gt Open un
19. til the file is saved from pBlazeIDE To initialize the simulation process and escape editing mode use menu Simulation Simulation The simulation toolbar provides basic stepping features for simulation and debugging such as reset step one step over breakpoints etc see menu Simulation Binary Image and VHDL To use Xilinx PicoBlaze 3 processor and the program written in its assembler PicoBlaze 3 psm you have to generate binary image of the instruction memory and HDL Hardware Description Language templates that can be integrated in your hardware design KCPSM3 exe see 1 2 is a command line tool processing the PicoBlaze 3 Assembler and producing the HEX and HDL VHDL or Verilog files The only argument is the filename with the assembler Next files Rom_form vhdlvlcoe are required It generates several resulting files approx 15 for more details see PicoBlaze manual including ROM content and some statistics the list of labels the list of constants etc PBCC Compilation from Source Code As there is new major version of SDCC 3 0 1 we upgraded the whole front end project to this version Then we introduce step by step tutorial how to compile the SDCC source codes including PicoBlaze 3 pblaze port in Cygwin at Microsoft Windows platform 1 Run Cygwin bash shell and open directory with source codes of SDCC 2 Generate configuration file configure from configure in autoconf 3 Create all makefiles confi
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