From 0f3ba405eada72e1ab4371948315b28608903927 Mon Sep 17 00:00:00 2001 From: Matt Turner Date: Fri, 14 Sep 2012 16:04:40 -0700 Subject: [PATCH] Use signbit() in IS_NEGATIVE and DIFFERENT_SIGNS signbit() appears to be available everywhere (even MSVC according to MSDN), so let's use it instead of open-coding some messy and confusing bit twiddling macros. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54805 Reviewed-by: Paul Berry Suggested-by: Ian Romanick --- configure.ac | 7 +++++++ src/mesa/main/macros.h | 21 ++------------------- 2 files changed, 9 insertions(+), 19 deletions(-) diff --git a/configure.ac b/configure.ac index 4193496de95..cb654675833 100644 --- a/configure.ac +++ b/configure.ac @@ -499,6 +499,13 @@ AC_SUBST([DLOPEN_LIBS]) dnl See if posix_memalign is available AC_CHECK_FUNC([posix_memalign], [DEFINES="$DEFINES -DHAVE_POSIX_MEMALIGN"]) +dnl signbit() is a macro in glibc's math.h, so AC_CHECK_FUNC fails. To handle +dnl this, use AC_CHECK_DECLS and fallback to AC_CHECK_FUNC in case it fails. +AC_CHECK_DECLS([signbit],[], + AC_CHECK_FUNC([signbit],[], + AC_MSG_ERROR([could not find signbit()])), + [#include ]) + dnl SELinux awareness. AC_ARG_ENABLE([selinux], [AS_HELP_STRING([--enable-selinux], diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h index 04d59d79c07..7b7fd1b6d76 100644 --- a/src/mesa/main/macros.h +++ b/src/mesa/main/macros.h @@ -693,31 +693,14 @@ NORMALIZE_3FV(GLfloat v[3]) static inline GLboolean IS_NEGATIVE(float x) { -#if defined(USE_IEEE) - fi_type fi; - fi.f = x; - return fi.i < 0; -#else - return x < 0.0F; -#endif + return signbit(x) != 0; } - /** Test two floats have opposite signs */ static inline GLboolean DIFFERENT_SIGNS(GLfloat x, GLfloat y) { -#if defined(USE_IEEE) - fi_type xfi, yfi; - xfi.f = x; - yfi.f = y; - return !!((xfi.i ^ yfi.i) & (1u << 31)); -#else - /* Could just use (x*y<0) except for the flatshading requirements. - * Maybe there's a better way? - */ - return ((x) * (y) <= 0.0F && (x) - (y) != 0.0F); -#endif + return signbit(x) != signbit(y); }