Re: [Qemu-devel] [PATCH] S/390 host fixed

[Thiemo Seufer]

Ulrich Hecht wrote:
> On Monday 30 July 2007 13:49, Ulrich Hecht wrote:
> > S/390 host support has been broken for a long time (since 0.4.2 or
> > something like that). I finally got around to fix it, adding
> > disassembly support on the way.
> 
> And here's an even better patch that also fixes non-i386 targets. MIPS 
> needs a little workaround to keep GCC from creating a jump table, 
> something that dyngen cannot handle. Alpha does not build because of an 
> ICE.

I committed the bits I were comfortable with, which left those:

[snip]
> @@ -300,7 +300,7 @@
>  if [ "$bsd" = "yes" -o "$darwin" = "yes" -o "$mingw32" = "yes" ] ; then
>      AIOLIBS=
>  else
> -    AIOLIBS="-lrt"
> +    AIOLIBS="-lrt -lpthread"

Why is this needed? Linux toolchains should add -lpthread implicitly.

[snip]
> diff -ruN qemu/target-alpha/op_helper.c qemu-s390/target-alpha/op_helper.c
> --- qemu/target-alpha/op_helper.c     2007-04-05 06:58:33.000000000 +0000
> +++ qemu-s390/target-alpha/op_helper.c        2007-07-30 12:16:31.000000000 
> +0000
> @@ -1229,6 +1229,9 @@
>      CPUState *saved_env;
>      target_phys_addr_t pc;
>      int ret;
> +#ifdef __s390__
> +    retaddr = (void*)((unsigned long)retaddr & 0x7fffffffUL);
> +#endif

All of those look weird. Is this a null-extension vs. sign-extension
issue?

[snip]
> diff -ruN qemu/target-i386/translate.c qemu-s390/target-i386/translate.c
> --- qemu/target-i386/translate.c      2007-06-26 08:35:18.000000000 +0000
> +++ qemu-s390/target-i386/translate.c 2007-07-30 13:57:39.000000000 +0000
> @@ -1795,7 +1795,11 @@
>          case CC_OP_SUBW:
>          case CC_OP_SUBL:
>          case CC_OP_SUBQ:
> +#ifdef __s390__
> +            func = NULL; /* does not work on S/390 for unknown reasons */
> +#else
>              func = gen_jcc_sub[s->cc_op - CC_OP_SUBB][jcc_op];
> +#endif

Hum. It wold be good to know what happens here.

[snip]
> diff -ruN qemu/target-mips/op.c qemu-s390/target-mips/op.c
> --- qemu/target-mips/op.c     2007-06-25 17:34:33.000000000 +0000
> +++ qemu-s390/target-mips/op.c        2007-07-30 13:34:08.000000000 +0000
> @@ -1616,6 +1616,18 @@
>  
>  void op_cfc1 (void)
>  {
> +#ifdef __s390__
> +    if(!T1)
> +        T0 = (int32_t)env->fcr0;
> +    else if(T1 == 25)
> +        T0 = ((env->fcr31 >> 24) & 0xfe) | ((env->fcr31 >> 23) & 0x1);
> +    else if(T1 == 26)
> +        T0 = env->fcr31 & 0x0003f07c;
> +    else if(T1 == 28)
> +        T0 = (env->fcr31 & 0x00000f83) | ((env->fcr31 >> 22) & 0x4);
> +    else
> +        T0 = (int32_t)env->fcr31;
> +#else    

I guess this breaks when you _breathe_ at the compiler. Inventing
switch-table support in dyngen would be preferable (if possible...).


Thiemo