Re: [Qemu-devel] [PATCH] target-mips: fix translation of MT instructions

[Aurelien Jarno]

On Fri, Oct 29, 2010 at 07:48:46AM -0700, Nathan Froyd wrote:
> The translation of dmt/emt/dvpe/evpe was doing the moral equivalent of:
> 
>   int x;
>   ...         /* no initialization of x */
>   x = f (x);
> 
> which confused later bits of TCG rather badly, leading to crashes.
> 
> Fix the helpers to only return results (those instructions have no
> inputs), and fix the translation code accordingly.
> 
> Signed-off-by: Nathan Froyd <address@hidden>

Thanks, applied.

> ---
>  target-mips/helper.h    |    8 ++++----
>  target-mips/op_helper.c |   28 ++++++++--------------------
>  target-mips/translate.c |    8 ++++----
>  3 files changed, 16 insertions(+), 28 deletions(-)
> 
> diff --git a/target-mips/helper.h b/target-mips/helper.h
> index cb13fb2..297ab64 100644
> --- a/target-mips/helper.h
> +++ b/target-mips/helper.h
> @@ -154,10 +154,10 @@ DEF_HELPER_2(mttlo, void, tl, i32)
>  DEF_HELPER_2(mtthi, void, tl, i32)
>  DEF_HELPER_2(mttacx, void, tl, i32)
>  DEF_HELPER_1(mttdsp, void, tl)
> -DEF_HELPER_1(dmt, tl, tl)
> -DEF_HELPER_1(emt, tl, tl)
> -DEF_HELPER_1(dvpe, tl, tl)
> -DEF_HELPER_1(evpe, tl, tl)
> +DEF_HELPER_0(dmt, tl)
> +DEF_HELPER_0(emt, tl)
> +DEF_HELPER_0(dvpe, tl)
> +DEF_HELPER_0(evpe, tl)
>  #endif /* !CONFIG_USER_ONLY */
>  
>  /* microMIPS functions */
> diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
> index 41abd57..ec6864d 100644
> --- a/target-mips/op_helper.c
> +++ b/target-mips/op_helper.c
> @@ -1554,40 +1554,28 @@ void helper_mttdsp(target_ulong arg1)
>  }
>  
>  /* MIPS MT functions */
> -target_ulong helper_dmt(target_ulong arg1)
> +target_ulong helper_dmt(void)
>  {
>      // TODO
> -    arg1 = 0;
> -    // rt = arg1
> -
> -    return arg1;
> +     return 0;
>  }
>  
> -target_ulong helper_emt(target_ulong arg1)
> +target_ulong helper_emt(void)
>  {
>      // TODO
> -    arg1 = 0;
> -    // rt = arg1
> -
> -    return arg1;
> +    return 0;
>  }
>  
> -target_ulong helper_dvpe(target_ulong arg1)
> +target_ulong helper_dvpe(void)
>  {
>      // TODO
> -    arg1 = 0;
> -    // rt = arg1
> -
> -    return arg1;
> +    return 0;
>  }
>  
> -target_ulong helper_evpe(target_ulong arg1)
> +target_ulong helper_evpe(void)
>  {
>      // TODO
> -    arg1 = 0;
> -    // rt = arg1
> -
> -    return arg1;
> +    return 0;
>  }
>  #endif /* !CONFIG_USER_ONLY */
>  
> diff --git a/target-mips/translate.c b/target-mips/translate.c
> index d62c615..c4c44c1 100644
> --- a/target-mips/translate.c
> +++ b/target-mips/translate.c
> @@ -12033,22 +12033,22 @@ static void decode_opc (CPUState *env, DisasContext 
> *ctx, int *is_branch)
>                  switch (op2) {
>                  case OPC_DMT:
>                      check_insn(env, ctx, ASE_MT);
> -                    gen_helper_dmt(t0, t0);
> +                    gen_helper_dmt(t0);
>                      gen_store_gpr(t0, rt);
>                      break;
>                  case OPC_EMT:
>                      check_insn(env, ctx, ASE_MT);
> -                    gen_helper_emt(t0, t0);
> +                    gen_helper_emt(t0);
>                      gen_store_gpr(t0, rt);
>                      break;
>                  case OPC_DVPE:
>                      check_insn(env, ctx, ASE_MT);
> -                    gen_helper_dvpe(t0, t0);
> +                    gen_helper_dvpe(t0);
>                      gen_store_gpr(t0, rt);
>                      break;
>                  case OPC_EVPE:
>                      check_insn(env, ctx, ASE_MT);
> -                    gen_helper_evpe(t0, t0);
> +                    gen_helper_evpe(t0);
>                      gen_store_gpr(t0, rt);
>                      break;
>                  case OPC_DI:
> -- 
> 1.6.3.2
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net