Chapter 14. CGC Domain
Contents
1. printf Settable states are n FOO tdefault 1 0 n BAR tdefault 0 01 n exit 0 if strcemp arg i FOO if arg i 1 arg_store FOO atof arg i 1 Ptolemy Last updated 10 17 97 14 4 CGC Domain continue if strcemp arg i BAR if arg i 1 arg_store BAR atof arg i 1 continue main function main int argc char argv double value_11 double value_12 End of Declaration set_arg_val argv Begin of Initialization value_12 arg_store BAR value_ll arg_store FOO Code The default values set by the edit parameters command are stored in the struct arg_store The function set_arg_val argv scans the list of command line arguments for FOO and BAR and sets the corresponding member in arg_store It also builds up the help message consist of the settable state names and their default values to be printed when the program receives a h help or HELP option The state values are initialized to the cor responding arg_store members during the variable initialization stage By doing this a state will get its default value if it is not set on the command line 14 4 2 Changes in pigiRpc to support command line arguments The pragma mechanism in the Target base class is used to specify the state that is to be made settable via command line arguments as well as to store the name to be used on the command line In cGCtarget these are stor2. FALSE otherwise These methods are member functions of the CGCStar class int addinclude const char file Generate the directive include file inthe include stream The string file must include quotation marks file or angle brackets lt file gt around the name of the file to be included Only one include file directive will be generated for the file even if addInclude is invoked multiple times with the same argument Return TRUE if a new directive was generated int addDeclaration const char text const char name NULL Add text to the mainDecls stream Use name as the identify ing key for the code fragment if it is provided otherwise use Ptolemy Last updated 10 17 97 14 2 CGC Domain text itself as the key Code will be added to the stream only the first time that a particular key is used int addGlobal const char text const char name NULL Add text to the globalDecls stream Use name as the identi fying key for the code fragment if it is provided otherwise use text itself as the key Code will be added to the stream only the first time that a particular key is used int addCompileOption const char text Add options to be used when compiling a C program The options are collected in the compileOptionsStream stream int addLinkOption const char text Add options to be used when linking a C program The options are collected in the 1inkOptionsStream stream The following streams which
3. are used by the code generation methods just described are defined as members of the CGCTarget class in addition to the streams defined by the CGTarget class CodeStream include Include directives are added to this stream by the addInclude method of CGCStar CodeStream mainDecls Local declarations for variables are added to this stream by the addDeclaration method of cGcStar CodeStream globalDecls Global declarations for variables and functions are added to this stream by the addGlobal method of CGCStar CodeStream mainInit Initialization code is added to this stream when the addCode method is invoked from within the initCode method CodeStream mainClose Code generated when the addCode method is invoked from within the wrapup method of stars is placed in this stream CodeStream compileOptionsStream Options to be passed to the C compiler which have been added using the CGCStar addCompileOption method CodeStream linkOptionsStream Options to be passed to the linker which have been added using the CGCStar addLinkOption method 14 3 Buffer Embedding Although many of the methods related to buffer embedding are actually implemented in the CG domain only the CGC domain makes use of them at this time The following func U C Berkeley Department of EECS The Almagest 14 3 tion is defined as a method of the CGPortHole class void embed CGPortHole port int location 1 Embed the buffer of port in the buffer
4. of this porthole with offset location The default location of 1 indicates that the offset is not yet determined For example the following statements appear in the setup method of the Switch block This causes the buffers of t rueOut put and falseOutput to be embedded within the buffer of input input embed trueOutput 0 input embed falseOutput 0 14 4 Command line Settable States In the Ptolemy releases before Ptolemy0 6 the C programs generated by Ptolemy in the CGC domain did not take any command line arguments The state values of the various stars were set during compilation and thus hard coded into the program In order to change a state variable the code had to be recompiled again i e the universe had to be re run within Ptolemy This was time consuming and it also placed unnecessary load on the machine In Ptolemy0 6 and later the CGC domain can generate C code that allow users to set the state values from the command line which allows runs with different parameters to be executed and compared quickly and easily Implementation 14 4 1 C code generated to support command line arguments A sample of the additional code generated to support command line arguments is shown below struct double FOO double BAR arg_store 1 0 0 01 void set_arg_val char arg ant is for i 1 arg i i if stremp arg i help I stremp arg i HELP stremp arg i h
5. time Speed There are several areas that can affect the amount of time that it takes a CGC universe to compile we discuss them below e Large sample rate changes and large delays can result in Ptolemy taking a very long time to generate C code A symptom of this sort of problem is that the pigiRpc pro cess will consume all the available swap and eventually crash If you feel you need really large delays James Lundblad suggests writing your own code in your stars that provides the same functionality as delays but uses malloc in the initCode sec tion instead of the array that is created by the CGC Delay icon e C compiler optimizers do not work well with functions that have thousands of lines The main function of a CGC simulation may be too large for the peephole opti mizer causing the optimizer to take a long time to compile the file Under gcc you can pass the 00 option to turn off the optimizer 14 6 BDF Stars Because the class CGCPortHole is not derived from BDFPortHole the setBDF Params method described in BDF Domain on page 8 1 is not available for code generation stars Use the setRelation method of DynDFPortHole instead void setRelation DFRelation relation DynDFPortHole assoc Specify the relation of this port with the associated porthole assoc There are five possible values for relation DF_NONE no relationship DF_TRUE produces consumes data only when assoc has a TR
6. The Almagest 14 1 Chapter 14 CGC Domain Authors Joseph T Buck Soonhoi Ha Edward A Lee Yu Kee Lim Thomas M Parks Jos Luis Pino Other Contributors Sunil Bhave Kennard White 14 1 Introduction The CGC domain generates code for the C programming language Code Generation on page 13 1 describes the features common to all code generation domains The basic princi ples of writing code generation stars are explained in Writing Code Generation Stars on page 13 2 You will find explanations for codeblocks macros and attributes there This chap ter explains features specific to the CGC domain Refer to the CGC domain chapter in the user s manual for an introduction to this domain 14 2 Code Generation Methods The addCode method is context sensitive so that it will do the right thing when invoked from within the initCode go and wrapup methods of cGcStar Refer to Writing Code Generation Stars on page 13 2 for documentation on addCode including context sen sitive actions and conditional code generation There are several additional code generation methods defined in the CGC domain The addInclude method is used to generate include file directives The addDeclaration method is used to declare local variables within the main function The addGlobal method is used to declare global variables outside the main function As with addCode these methods return TRUE if code was generated for the appropriate stream and
7. UE particle DF_FALSE _ produces consumes data only when assoc has a FALSE particle DF_SAME signal is logically the same as assoc DF_COMPLEMENT signal is the logical complement of ASSOC For example the following statements describe the relationships among the portholes of the Switch block trueOutput setRelation DF TRUE control U C Berkeley Department of EECS The Almagest 14 7 falseOutput setRelation DF FALSE control 14 7 Tcl Tk Stars The CGCTclTkTarget class defines the tkSetup stream for Tcl Tk stars There is no special code generation function for this stream so its name must be used with addCode This is usually done from within the initCode method addCode codeblock tkSetup The following functions which are defined in the file tkMain c can be used within codeblocks of Tcl Tk stars in the CGC domain void errorReport char message This functions creates a pop up window containing message void makeEntry char window char name char desc char initValue Tcl CmdProc callback This function creates an entry box in a window The name of the entry box must be unique e g derived from the star name The description of the entry box is desc The initial value in the entry box is initValue A callback function is called whenever the user enters a RET in the box The argument to the callback function will be the value that the user has put in the entry box The return value of the callb
8. ack func tion should be TCL_OK void makeButton char window char name char desc Tcl Cmd Proc callback This function creates a push button in a window The name of the push button must be unique e g derived from the star name The description of the push button is desc A callback function is called whenever the user pushes the button The return value of the callback function should be TCL_OK void makeScale char window char name char desc int posi tion Tcl CmdProc callback This function creates a scale with slider in a window The name of the scale must be unique e g derived from the star name The description of the push button is desc The initial position of the slider must be between 0 and 100 A callback function is called whenever the user moves the slider in the scale The argument to the callback function will be the current position of the slider which can range from 0 to 100 The return value of the callback function should be TCL_OK void displaySliderValue char window char name char value Ptolemy Last updated 10 17 97 14 8 CGC Domain This function displays a value associated with a scale s slider The scale is identified by its name and the window it is in This function must be called by the user of the slider Only the first 6 characters of the value will be used 14 8 Tycho Target The CGC TychoTarget is an experimental target that provides a way to create CGC con
9. ea to use the put method in CodeSt ream to add the st ruct member with its unique handle to the appropriate CodeSt ream That way there will not be duplicate struct members and state variables could still reference the same member so that two or more states could be set to the same value from a single argument on the command line Another limitation is that the command line capability only works for states of blocks at the top level It will not work for states of Galaxies and Universes and states that refer Ptolemy Last updated 10 17 97 14 6 CGC Domain enced other settable states This could probably be solved by modifying the pragma mecha nism to ensure that pragmas at the top level propagate all the way down to the contained blocks By doing this states will inherit pragmas from their parent galaxies so that these can be picked up by the isCmdArg function and the appropriate codes can be generated Certain states will affect the overall scheduling of the whole system e g the factor of upsampling and downsampling stars and changing these would mean that new code needs to be generated since the scheduling is hard coded into the generated code Thus these should not be allowed to take values from the command line A new attribute can be intro duced to identify those states that should not be settable from the command line Warnings can then be generated if users attempt to specify these for command line setting 14 5 CGC Compile
10. ed as a character string in a Text Table map pings a pointer to a HashTable in which the data value and index are character strings via the overloaded pragma member functions A function isCmdArg const State state is used to check whether state is to be set by a command line argument It calls CGCTarget pragma and scans through the StringList returned for the state s name If found the mapped name is return Other wise a null string is return Four new protected CodeStream are added to CGCTarget to store the additional codes cmdargStruct stores the struct members U C Berkeley Department of EECS The Almagest 14 5 emdargStruct stores the default values setargFunc stores the code segment in set_arg_val setargFuncHelp stores the built up help message Four new public member functions and four private ones are also added to CGCStar to generate the codes cmdargStates calls cmdargState to generate the members of struct arg_store using the mapped name returned by isCmdArg cmdargStatesInits calls cmdargStatesInit to generate the default values of the settable states setargStates calls setargState to generate the code segment to match the mapped name to the command line options setargStatesHelps calls setargStatesHelp to build up the help message These are called in the CGCTarget declareStar CGCStar star function after the global and main declaratio
11. ns have been generated CGCStar initCod eState const State state is modified to generate the required initialization code if state is to be settable from the command line In order for a va1 state to be settable from the command line it has to be changed to a reference state The expandVal member function is overloaded in CGCStar to check if the name state is to be made settable from the command line If so it is added to the list of referenced state so that it will be declared and initialized 14 4 3 Limitations of command line arguments Currently this implementation works only for scalar states with float or integer values Extension to other types of state should be straight forward by simply adding the appropriate struct member declaration code in CGCStar cmdargState const State state The cmdargStatesInit setargState setargStatesHelp and initCode String member functions need to be modified accordingly to generate codes for the ini tialization setting function help message and assignment respectively of the new state variable Also there is no provision to check for duplicate command line names If there are duplicates Ptolemy will simply generate multiple st ruct members with the same name and error will result in the generated code To get around this a new Tk interface could be written to specify and set the settable states and checking can be done at that level Alternatively it might be a better id
12. trol panels that use the functionality in Tycho A universe that uses TychoTarget must pro vide a script that creates the control panel that the user sees The TychoTarget is documented in SPTOLEMY demo whats_new whats_new0 7 tychotarget html U C Berkeley Department of EECS
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