VBCC ARM backend possible?

[Hedeon]

Hi,

What exactly would be needed to make VBCC process C code in a way so vasm in turn can output ARM assembly code?

In other words, what is needed to make an ARM backend for VBCC?

[robinsonb5]

Originally Posted by Hedeon

Hi,

What exactly would be needed to make VBCC process C code in a way so vasm in turn can output ARM assembly code?

In other words, what is needed to make an ARM backend for VBCC?

You'll need a vbcc backend that emits ARM assembly, which vasm will in turn assemble into object code.

VBCC has a really neat backend interface, and it's well documented too - see http://www.ibaug.de/vbcc/doc/vbcc_13.html

If you're interested in creating a new backend, start by reading the generic RISC backend, understand what it's doing, then probably the best path is to copy it and adapt it gradually to the target instruction set.

It'd be worth checking with phx and Volker Barthelmann first, though, to make sure no-one's already working on such a thing.

[Hedeon]

Thanks. Seeing the emerging use of ARM coprocessors in some cards already on the market (zz9000) and upcoming cards (warp) it might be something worthwhile to look at.

[polluks]

Already possible
> type t:a.c
main()
{
return 42;
}
> bin/vbccarm t:a.c
vbcc V0.9h pre (c) in 1995-2020 by Volker Barthelmann
vbcc code-generator for ARM V0.0 (c) in 2006 by Frank Wille
> type t:a.asm
.file "t:a.c"
.text
.global _main
_main:
mov r0,#42
l1:
mov pc,lr
.type _main,@function
.size _main,.-_main

[Hedeon]

I missed this post. Are those binaries on the vbcc site?

[robinsonb5]

Originally Posted by Hedeon

I missed this post. Are those binaries on the vbcc site?

The experimental ARM code is in the source snapshot on Volker Barthelmann's site: http://www.compilers.de/vbcc.html - but I believe it was only preliminary, it's not yet in a useful state. I asked him about it a few weeks ago and he said that because ARM is so well supported elsewhere it's not a very interesting target for VBCC, which makes sense.

[Hedeon]

Ah, bummer. I like to develop on Amiga itself. Call me masochistic. But it's a reason to turn the machine on :-)

[phx]

Oh, the year is 2006. This must have been the time after I finished my first ARM backend for vasm. I thought I might try a vbcc-backend for ARM as well ... but failed (it was my first and only attempt for a vbcc-backend).

This doesn't mean it is difficult. RISC-backends are usually on the easier side. Somebody with the experience of robinson5, who already wrote a working vbcc-backend, could certainly do it. Or try it yourself, and we would help you!