Post by thread:C compiler in java for PIC

I'm a engineer student, for the next exam i have to make a C compiler for the PIC microcontroller. I know the C language for Unix, Dos, windows, ecc. but I don't now the characteristic of a C for a microcontroller. There are some special instruction? I had read some source of PIC C program, what is the content of <pic.h>? and <conio.h>? Any suggestion is welcome. Thanks in advance. Giorgio Alboni. =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: spam_OUTrac1337TakeThisOuTracine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 (Last Update: 29/09/97) ===================================================

Remeber that a compiler generates the machine language (i.e. op codes with data) for the target processor. So you would need to learn the PIC opcodes and such so that you can compile the C code into PIC opcodes. Since you are suppose to wrate a compiler I woulde assume that your free to design it as you wish. Giorgio Alboni wrote: {Quote hidden}> > I'm a engineer student, for the next exam i have to make a C compiler for > the PIC microcontroller. I know the C language for Unix, Dos, windows, ecc. > but I don't now the characteristic of a C for a microcontroller. > There are some special instruction? I had read some source of PIC C > program, what is the content of <pic.h>? and <conio.h>? > Any suggestion is welcome. > Thanks in advance. > Giorgio Alboni. > > =================================================== > Alboni Giorgio > Faenza (Ra) ITALY > E-Mail: .....rac1337KILLspam@spam@racine.ravenna.it > > www.geocities.com/SiliconValley/Heights/5444 > (Last Update: 29/09/97) > ===================================================

At 07.01 09/01/98 -0500, you wrote: >Remeber that a compiler generates the machine language (i.e. op codes >with data) for the target processor. >So you would need to learn the PIC opcodes and such so that you can >compile the C code into PIC opcodes. The output of the compiler is assembler code (text file) for the mplab. >Since you are suppose to wrate a compiler I woulde assume that your free >to design it as you wish. OK, but i prefer use a standar grammar for the source code with the neccessary extension at C lenguager for manege a assembler code. Giorgio Alboni. =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: rac1337KILLspamracine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 (Last Update: 29/09/97) ===================================================

At 10:30 AM 1/9/98 +0100, you wrote: >I'm a engineer student, for the next exam i have to make a C compiler for >the PIC microcontroller. I know the C language for Unix, Dos, windows, ecc. >but I don't now the characteristic of a C for a microcontroller. >There are some special instruction? I had read some source of PIC C >program, what is the content of <pic.h>? and <conio.h>? >Any suggestion is welcome. >Thanks in advance. >Giorgio Alboni. If you make the C compiler, then YOU decide what features to include. You are the one who writes the functions. You will need to concentrate on the I/O, timer, and interrupts. Make sure the functions you give to a programmer will do most of the things that embedded programmers need to do. You may want to check out the BASIC Stamp instructions to get ideas. Things like "shiftout", "debug", and port configuration (setting bits as inputs or outputs, then reading from them or writing to them. It sounds to me like you've taken on a monumental task for a college class. You need to use a small PIC as your target to keep it easier on you. I'd use one of the small 8 pin PICS as the target (12c509, etc). You can use yacc and lex if you want to create a state-machine parser, but recursive descent is easier. I'd choose to use a public domain Small C compiler, and just create a code generator (and maybe an optimizer) for it. You'll also need to create a run-time library for it. Will your teacher allow that (so you don't have to write a lexer, parser, etc)? Do a Web search for "GNU pic" and you'll see some stuff about folks who are converting some GNU tools to target the PIC. I don't know if they have a working C compiler yet. There is a good referance book on Small C by James Hendrix. Dr Dobbs Journal has published a CD with that complete book, and lots of other similar stuff on it. The only part that needs changing is the code generator (and, of couse, you'll need a RTL). You will have to be very fluent with PIC assembler in order to create a code generator for the PIC. Another option would be the Micro C compiler. Dave Dunfield wrote the Micro C compiler - it already has code generators for many different embedded processors. Do a Web search for Dunfield and "Micro C". Eric Engler

At 18.10 10/01/98 -0700, you wrote: >If you make the C compiler, then YOU decide what features to >include. You are the one who writes the functions. > >You will need to concentrate on the I/O, timer, and interrupts. >Make sure the functions you give to a programmer will do most of the >things that embedded programmers need to do. You may want to >check out the BASIC Stamp instructions to get ideas. Things like >"shiftout", "debug", and port configuration (setting bits as inputs >or outputs, then reading from them or writing to them. > >It sounds to me like you've taken on a monumental task for >a college class. You need to use a small PIC as your target to >keep it easier on you. I'd use one of the small 8 pin PICS as >the target (12c509, etc). I'm doing the last year of university (engineering). I use the PIC 16C84. >You can use yacc and lex if you want to create a state-machine >parser, but recursive descent is easier. I'd choose to use >a public domain Small C compiler, and just create a code >generator (and maybe an optimizer) for it. You'll also need to >create a run-time library for it. Will your teacher allow >that (so you don't have to write a lexer, parser, etc)? I'm using a recursive descent parser (or a table driven?), it's easy to make. The real problem is run-time library. PIC microcontroller haven't a stack area, so there are some problem to pass variables and manage the free register. {Quote hidden}>Do a Web search for "GNU pic" and you'll see some stuff about folks >who are converting some GNU tools to target the PIC. I don't know >if they have a working C compiler yet. > >There is a good referance book on Small C by James Hendrix. >Dr Dobbs Journal has published a CD with that complete book, >and lots of other similar stuff on it. The only part that >needs changing is the code generator (and, of couse, you'll >need a RTL). You will have to be very fluent with PIC assembler in >order to create a code generator for the PIC. > >Another option would be the Micro C compiler. Dave Dunfield >wrote the Micro C compiler - it already has code generators >for many different embedded processors. Do a Web search for >Dunfield and "Micro C". > Thanks for your help, I've found some good compiler at: http://hem.passagen.se/zeela/ Bye. =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: .....rac1337KILLspam.....racine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 (Last Update: 29/09/97) ===================================================

> I'm using a recursive descent parser (or a table driven?), it's easy to make. > The real problem is run-time library. PIC microcontroller haven't a stack > area, so there are some problem to pass variables and manage the free > register. There is often an assumption that C needs a stack frame for locals or argument passing. There is nothing in the language that dictates this. One of the reasons that C as a language is popular is that it maps quite well on many different processor architectures. A lot of the recent work we have been doing with C tools for embedded systems has shown that C can have diverse memory spaces far more than Harvard architecture processors have. We have shown that Locals and argument passing can be handled in ways unique to each processor and the resulting compilers can pass both standard C conformance tests and portability tests. Walter Banks

> > I'm using a recursive descent parser (or a table driven?), it's easy to > make. > > The real problem is run-time library. PIC microcontroller haven't a stack > > area, so there are some problem to pass variables and manage the free > > register. > > > There is often an assumption that C needs a stack frame for locals or > argument passing. There is nothing in the language that dictates this. One > of the reasons that C as a language is popular is that it maps quite well > on many different processor architectures. One simple approach that works well for local variables (somewhat less well for argument passing) is to figure out where on the stack each variable would go, worst-case, on a stack-based machine. For non-recursive programs, it's always possible to assign addresses in this way, and the number of addresses required by this method will equal the maximum depth that the program could need if it used a stack. The only drawback to this approach (or a bottom-up approach which yields the same memory requirements, but orders things differently) is that special care needs to be used for parameter marshalling. For example, consider this program: int foo(int p, int q) {return p+q;} int boz(int s, int t) {return s*t;} int bar(int u, int v) {return u-v;} int floozle(int ss, int tt, int uu, int vv) { return foo(boz(ss,tt),bar(uu,vv)); } It isn't possible to use a fixed address for foo's parameters unless some other area is used for "parameter martialling". In particular, a compiler given the above code should translate the last function into: int floozle(int ss, int tt, int uu, int vv) { int temp1; boz.s = ss; boz.t = tt; CALL boz; temp1 = RESULT; bar.u = uu; bar.v = vv; CALL bar; foo.p = temp1; foo.q = RESULT; CALL foo; } where function.param is the variable allocated to that function's parameter, and RESULT is a system global used to hold function return values. If the compiler always allocates a temp for all but one of the "complex" parameters to a function, it will work okay though it will in many cases generate data moves that turn out to be redundant. On the other hand, all of the PIC-based compiles I've seen choke on the above example program, so maybe parameter marshalling may be safely ignored in practice (since such programs are rare).

part 0 653 bytes thanks John, this method seems to me that is good. Not so good for argument passing but for a beta it can be ok. My goal is to make a simple c compiler thats product a asm code for MPLAB, full commented and easy to modify with a no run time support (or very small and easy to understand = modify). Take a look at the grammar. Bye. Attachment converted: wonderland:Grammar.htm (TEXT/ttxt) (0000FA14) =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: EraseMErac1337spam_OUTTakeThisOuTracine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 (Last Update: 29/09/97) ===================================================