On 09/12/2014 01:56, Maciej W. Rozycki wrote:
> + if (info->elf_flags & EF_MIPS_NAN2008)
> + env->active_fpu.fcr31 |=
> + (1 << FCR31_NAN2008) & env->active_fpu.fcr31_rw_bitmask;
> + else
> + env->active_fpu.fcr31 &=
> + ~((1 << FCR31_NAN2008) & env->active_fpu.fcr31_rw_bitmask);
braces are needed here
> +uint64_t helper_float_chs_d(CPUMIPSState *env, uint64_t fdt0)
> +{
> + uint64_t fdt1;
> +
> + fdt1 = float64_sub(0, fdt0, &env->active_fpu.fp_status);
> + update_fcr31(env, GETPC());
> + return fdt1;
> +}
> +
> +uint32_t helper_float_chs_s(CPUMIPSState *env, uint32_t fst0)
> +{
> + uint32_t fst1;
> +
> + fst1 = float32_sub(0, fst0, &env->active_fpu.fp_status);
> + update_fcr31(env, GETPC());
> + return fst1;
> +}
I think there is one case where helper_float_chs_{d,s,ps} are not
correct -- when we have zero. In this case in subFloat32Sigs() we call:
return packFloat32(status->float_rounding_mode == float_round_down, 0, 0);
and the packFloat32() definition:
static inline float32 packFloat32(flag zSign, int_fast16_t zExp,
uint32_t zSig)
{
return make_float32(
( ( (uint32_t) zSign )<<31 ) + ( ( (uint32_t) zExp )<<23 ) +
zSig);
}
Which means that the sign may not get changed, whereas I believe NEG.fmt
is supposed to reverse the sign bit of positive/negative zero regardless
of rounding mode.
>
> enum {
> @@ -8718,7 +8719,10 @@ static void gen_farith (DisasContext *ct
> TCGv_i32 fp0 = tcg_temp_new_i32();
>
> gen_load_fpr32(fp0, fs);
> - gen_helper_float_abs_s(fp0, fp0);
> + if (ctx->abs2008)
> + gen_helper_float_abs2008_s(fp0, fp0);
> + else
> + gen_helper_float_abs_s(fp0, cpu_env, fp0);
braces are needed here too (and also in a few other places in this patch).
Thanks,
Leon
