[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] target-i386: Fix regression with maxsd SSE2 ins
From: |
Laurent Desnogues |
Subject: |
Re: [Qemu-devel] [PATCH] target-i386: Fix regression with maxsd SSE2 instruction |
Date: |
Tue, 8 Nov 2011 14:48:38 +0100 |
On Tue, Nov 8, 2011 at 2:00 PM, Jason Wessel <address@hidden> wrote:
> The maxsd instruction needs to take into account the sign of the
> numbers 64 bit numbers. This is a regression that was introduced in
> 347ac8e356 (target-i386: switch to softfloat).
>
> The case that fails is:
>
> maxsd %xmm1,%xmm0
>
> When xmm1 = 24 and xmm0 = -100
>
> This was found running the glib2 binding tests where it prints the message:
> /binding/transform:
> GLib-GObject-WARNING **: value "24.000000" of type `gdouble' is invalid or
> out of range for property `value' of type `gdouble'
> aborting...
>
> Using a signed comparison fixes the problem.
>
> Signed-off-by: Jason Wessel <address@hidden>
> ---
> target-i386/ops_sse.h | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/target-i386/ops_sse.h b/target-i386/ops_sse.h
> index aa41d25..bcc0ed9 100644
> --- a/target-i386/ops_sse.h
> +++ b/target-i386/ops_sse.h
> @@ -584,8 +584,8 @@ void helper_ ## name ## sd (Reg *d, Reg *s)\
> #define FPU_SUB(size, a, b) float ## size ## _sub(a, b, &env->sse_status)
> #define FPU_MUL(size, a, b) float ## size ## _mul(a, b, &env->sse_status)
> #define FPU_DIV(size, a, b) float ## size ## _div(a, b, &env->sse_status)
> -#define FPU_MIN(size, a, b) (a) < (b) ? (a) : (b)
> -#define FPU_MAX(size, a, b) (a) > (b) ? (a) : (b)
Isn't maxsd a floating-point instruction? If so, shouldn't
FPU_{MIN,MAX} use softfloat operations?
Laurent
> +#define FPU_MIN(size, a, b) (int ## size ## _t)(a) < (int ## size ## _t)(b)
> ? (a) : (b)
> +#define FPU_MAX(size, a, b) (int ## size ## _t)(a) > (int ## size ## _t)(b)
> ? (a) : (b)
> #define FPU_SQRT(size, a, b) float ## size ## _sqrt(b, &env->sse_status)
>
> SSE_HELPER_S(add, FPU_ADD)
> --
> 1.7.1
>
>
>