On 09/24/2012 10:49 AM, Matt Turner wrote:
Module: Mesa
Branch: master
Commit: 0f3ba405eada72e1ab4371948315b28608903927
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=0f3ba405eada72e1ab4371948315b28608903927
Author: Matt Turner<matts...@gmail.com>
Date: Fri Sep 14 16:04:40 2012 -0700
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<stereotype...@gmail.com>
Suggested-by: Ian Romanick<ian.d.roman...@intel.com>
---
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 4193496..cb65467 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<math.h>])
+
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 04d59d7..7b7fd1b 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);
}
Looks like we don't have signbit() on Windows. We build with scons
there so the autoconf check isn't applicable. I'll post a patch in a bit.
-Brian
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