Jason, ping? Are you going to do a v3 of this patch? Thanks -- PMM
On 19 November 2011 16:20, Peter Maydell <peter.mayd...@linaro.org> wrote: > On 8 November 2011 14:20, Jason Wessel <jason.wes...@windriver.com> 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. > > This commit comment needs to be updated -- we're not using a > signed comparison, we're using a floating point comparison. > >> diff --git a/target-i386/ops_sse.h b/target-i386/ops_sse.h >> index aa41d25..58f7bf5 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) >> +#define FPU_MIN(size, a, b) float ## size ## _lt(a, b, &env->sse_status) ? >> (a) : (b) >> +#define FPU_MAX(size, a, b) float ## size ## _lt(b, a, &env->sse_status) ? >> (a) : (b) >> #define FPU_SQRT(size, a, b) float ## size ## _sqrt(b, &env->sse_status) > > (repeating my comments from the other thread): > > Having mused about it a bit, I think that actually the macros > there do return the right answers for the special cases :-) > > If (a,b) are +0,-0 in some order, then the _lt comparison will > treat them as equal and return 0, so we return b, as required. > If either of (a,b) are NaNs then the _lt comparison will raise > InvalidOp and return 0, so we return b. > > That's a bit subtle, so I think it probably deserves a comment: > > /* Note that the choice of comparison op here is important to get the > * special cases right: for min and max Intel specifies that (-0,0), > * (0,-0), (NaN, anything) and (anything, NaN) return the second argument. > */ > > -- PMM
