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Various fixes to the ilog2 functions

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Fix several bugs in the ilog2 functions.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin 2016-11-15 14:23:54 -08:00
parent 069ad5fc18
commit 8d4fb26ad4
2 changed files with 13 additions and 6 deletions
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6
configure.ac
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@ -109,9 +109,9 @@ AC_CHECK_FUNCS(sysconf)
AC_CHECK_FUNCS([access _access faccessat])
PA_HAVE_FUNC(__builtin_ctz, (0U))
PA_HAVE_FUNC(__builtin_ctzl, (0UL))
PA_HAVE_FUNC(__builtin_ctzll, (0ULL))
PA_HAVE_FUNC(__builtin_clz, (0U))
PA_HAVE_FUNC(__builtin_clzl, (0UL))
PA_HAVE_FUNC(__builtin_clzll, (0ULL))
PA_HAVE_FUNC(__builtin_expect, (1,1))
dnl Functions for which we have replacements available in lib/

13
nasmlib/ilog2.c
View File

@ -33,6 +33,7 @@
#include "compiler.h"
#include "nasmlib.h"
#include <limits.h>
#define ROUND(v, a, w) \
do { \
@ -61,14 +62,20 @@ int ilog2_32(uint32_t v)
{
int n;
#ifdef __i686__
__asm__("bsrl %1,%0 ; cmovz %2,%0\n"
: "=&r" (n)
: "rm" (v), "r" (0));
#else
__asm__("bsrl %1,%0 ; jnz 1f ; xorl %0,%0\n"
"1:"
: "=&r" (n)
: "rm" (v));
return n;
#endif
return n;
}
#elif defined(HAVE___BUILTIN_CTZ) && INT_MAX == 2147483647
#elif defined(HAVE___BUILTIN_CLZ) && INT_MAX == 2147483647
int ilog2_32(uint32_t v)
{
@ -107,7 +114,7 @@ int ilog2_64(uint64_t v)
return n;
}
#elif defined(HAVE__BUILTIN_CTZLL) && LLONG_MAX == 9223372036854775807LL
#elif defined(HAVE__BUILTIN_CLZLL) && LLONG_MAX == 9223372036854775807LL
int ilog2_64(uint64_t v)
{