From 036e347f3c129bb547137aed955e75062fca09b8 Mon Sep 17 00:00:00 2001 From: Matt Turner Date: Wed, 18 Mar 2015 14:23:41 -0700 Subject: [PATCH] util: Optimize _mesa_roundeven with SSE 4.1. The SSE 4.1 ROUND instructions let us implement roundeven directly. Otherwise we assume that the rounding mode has not been modified (as we do in the rest of Mesa) and use rint(). glibc uses the ROUND instruction in rint() after a cpuid check. This patch just lets us inline it directly when we're already building for SSE 4.1. Reviewed-by: Carl Worth --- src/util/rounding.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/src/util/rounding.h b/src/util/rounding.h index c8be45057b6..0cbe9269f7b 100644 --- a/src/util/rounding.h +++ b/src/util/rounding.h @@ -23,6 +23,10 @@ #include +#ifdef __SSE4_1__ +#include +#endif + /* The C standard library has functions round()/rint()/nearbyint() that round * their arguments according to the rounding mode set in the floating-point * control register. While there are trunc()/ceil()/floor() functions that do @@ -45,7 +49,15 @@ static inline float _mesa_roundevenf(float x) { +#ifdef __SSE4_1__ + float ret; + __m128 m = _mm_load_ss(&x); + m = _mm_round_ss(m, m, _MM_FROUND_CUR_DIRECTION | _MM_FROUND_NO_EXC); + _mm_store_ss(&ret, m); + return ret; +#else return rintf(x); +#endif } /** @@ -54,5 +66,13 @@ _mesa_roundevenf(float x) static inline double _mesa_roundeven(double x) { +#ifdef __SSE4_1__ + double ret; + __m128d m = _mm_load_sd(&x); + m = _mm_round_sd(m, m, _MM_FROUND_CUR_DIRECTION | _MM_FROUND_NO_EXC); + _mm_store_sd(&ret, m); + return ret; +#else return rint(x); +#endif } -- 2.30.2