Mesa (master): util: Use win32 intrinsics for util_last_bit if present.
Mathias Fröhlich
frohlich at kemper.freedesktop.org
Wed Aug 10 07:31:36 UTC 2016
Module: Mesa
Branch: master
Commit: 0ce5ec8ece78f7936dc7bf0ad58fa1ed01783e25
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=0ce5ec8ece78f7936dc7bf0ad58fa1ed01783e25
Author: Mathias Fröhlich <mathias.froehlich at web.de>
Date: Sat Aug 6 07:26:51 2016 +0200
util: Use win32 intrinsics for util_last_bit if present.
v2: Split into two patches.
v3: Fix off by one problem.
Signed-off-by: Mathias Fröhlich <Mathias.Froehlich at web.de>
Reviewed-by: Brian Paul <brianp at vmware.com>
Tested-by: Brian Paul <brianp at vmware.com>
---
src/util/bitscan.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/src/util/bitscan.h b/src/util/bitscan.h
index 0743fe7..8afef81 100644
--- a/src/util/bitscan.h
+++ b/src/util/bitscan.h
@@ -157,6 +157,12 @@ util_last_bit(unsigned u)
{
#if defined(HAVE___BUILTIN_CLZ)
return u == 0 ? 0 : 32 - __builtin_clz(u);
+#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
+ unsigned long index;
+ if (_BitScanReverse(&index, u))
+ return index + 1;
+ else
+ return 0;
#else
unsigned r = 0;
while (u) {
@@ -177,6 +183,12 @@ util_last_bit64(uint64_t u)
{
#if defined(HAVE___BUILTIN_CLZLL)
return u == 0 ? 0 : 64 - __builtin_clzll(u);
+#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
+ unsigned long index;
+ if (_BitScanReverse64(&index, u))
+ return index + 1;
+ else
+ return 0;
#else
unsigned r = 0;
while (u) {
More information about the mesa-commit
mailing list