Re: [Tinycc-devel] looking for documentation for porting

[grischka]

On 16.01.2024 00:38, Michael Larson wrote:
> Hello,
>
> I have been tinkering around with TCC porting to a RISC cpu of my own
> design, I have my own C simulator and verilog targeted for a FPGA.. I
> have a lot of tests for functionality, but I need more so TCC looked
> like a good option to generate code for.
>
> I have been following some of the code samples given like the C67 and
> MIPS source, I have about half of it done but documentation on how
> this works seems to be really missing.
>
> I did a normal port, I copied all the functions out of the header
> files required and built a C file for them. This worked well... but..
> there are a lot of questions.
>
> Like
>
> int gjmp_cond(int op, int t)
>
> I look around the source and see a bunch of different implementations
> of this, but there is no documentation on how it's supposed to work? I
> am sure I could dig into it a bit more.. but it's time to ask where
> the documentation is, maybe I am missing something.. is there
> documentation out there?

No, because it's really so simple ;)

It's simply supposed to put the conditional jump opcode
as given in 'op', fill its address field with 't', and
return the offset of that field (ind - 4 after it was put).

There is also

     void gsym_addr(int t, int a)

which then is supposed to replace the field at offset 't'
with address 'a', and continue to do so with the former
contents of that field unless it's zero.

As you can see to write this little documentation already
was much more effort than it ever was or would be just to
write or read those functions. ;)

Other than that, the maybe as simple as possible single file
implementation of that stuff may be found in the first revision
of the repo here

   https://repo.or.cz/tinycc.git/blob/27f6e16b:/tcc.c

You'll find that for example the 'if' statement code in block()
is still almost identical to how it is now.

   https://repo.or.cz/tinycc.git/blob/27f6e16b:/tcc.c#l780

--- gr

> I only have a few functions left so I am not going to give up at this point.
>
> Thanks ahead of time,
>
> Mike
>
>
>
> ST_FUNC int gjmp_append(int n, int t)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> return 0;
> }
>
> ST_FUNC void gen_opi(int op)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_opf(int op)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_cvt_ftoi(int t)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_cvt_itof(int t)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_cvt_ftof(int t)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void ggoto(void)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_vla_sp_save(int addr)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_vla_sp_restore(int addr)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
> ST_FUNC void gen_vla_alloc(CType *type, int align)
> {
> printf("%s:%s unimplemented\n", __FUNCTION__, __FILE__);
> }
>
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