Re: [Qemu-devel] Re: Some patches for qemu on sparc

[Paul Brook <paul@codesourcery.com>]

> Thanks for your feedback. I've added additional check to dyngen.c, which
> checks that function has either save; in the beginning and ret; restore;
> in the end, or ends in retl; nop;. That allowed me to get past the arm
> target build failure. Now it fails (during dyngen check) on ppc target,
> the culprit is the following function:
>
> 000033d8 <op_stfs_raw>:
>      33d8:       9c 03 bf 90     add  %sp, -112, %sp
>      33dc:       d1 19 a0 f8     ldd  [ %g6 + 0xf8 ], %f8
>      33e0:       91 a0 18 c8     fdtos  %f8, %f8
>      33e4:       d1 23 a0 64     st  %f8, [ %sp + 0x64 ]
>      33e8:       c8 03 a0 64     ld  [ %sp + 0x64 ], %g4
>      33ec:       99 39 20 18     sra  %g4, 0x18, %o4
>      33f0:       97 39 20 10     sra  %g4, 0x10, %o3
>      33f4:       95 39 20 08     sra  %g4, 8, %o2
>      33f8:       c8 28 60 03     stb  %g4, [ %g1 + 3 ]
>      33fc:       d8 28 40 00     stb  %o4, [ %g1 ]
>      3400:       d6 28 60 01     stb  %o3, [ %g1 + 1 ]
>      3404:       d4 28 60 02     stb  %o2, [ %g1 + 2 ]
>      3408:       81 c3 e0 08     retl
>      340c:       9c 23 bf 90     sub  %sp, -112, %sp
>
> What should dyngen do about a function like that?

Maybe a better strategy is to force generation of a register window save with 
the FORCE_RET macro.

#define FORCE_RET() asm volatile("":::"o0");

Seems to do the trick.

Paul