remove a_ctz_l from arch specific atomic_arch.h

Update atomic.h to provide a_ctz_l in all cases (atomic_arch.h should
now only provide a_ctz_32 and/or a_ctz_64).

The generic version of a_ctz_32 now takes advantage of a_clz_32 if
available and the generic a_ctz_64 now makes use of a_ctz_32.
This commit is contained in:
Andre McCurdy 2018-04-18 17:40:59 -07:00 committed by Rich Felker
parent 3f6dc30470
commit 0c6abb5882
3 changed files with 28 additions and 24 deletions

View File

@ -92,10 +92,10 @@ static inline int a_ctz_64(uint64_t x)
return r;
}
#define a_ctz_l a_ctz_l
static inline int a_ctz_l(unsigned long x)
#define a_ctz_32 a_ctz_32
static inline int a_ctz_32(uint32_t x)
{
long r;
int r;
__asm__( "bsf %1,%0" : "=r"(r) : "r"(x) );
return r;
}

View File

@ -106,8 +106,8 @@ static inline int a_ctz_64(uint64_t x)
return x;
}
#define a_ctz_l a_ctz_l
static inline int a_ctz_l(unsigned long x)
#define a_ctz_32 a_ctz_32
static inline int a_ctz_32(uint32_t x)
{
__asm__( "bsf %1,%0" : "=r"(x) : "r"(x) );
return x;

View File

@ -251,6 +251,22 @@ static inline void a_crash()
}
#endif
#ifndef a_ctz_32
#define a_ctz_32 a_ctz_32
static inline int a_ctz_32(uint32_t x)
{
#ifdef a_clz_32
return 31-a_clz_32(x&-x);
#else
static const char debruijn32[32] = {
0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
};
return debruijn32[(x&-x)*0x076be629 >> 27];
#endif
}
#endif
#ifndef a_ctz_64
#define a_ctz_64 a_ctz_64
static inline int a_ctz_64(uint64_t x)
@ -261,22 +277,23 @@ static inline int a_ctz_64(uint64_t x)
63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10,
51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12
};
static const char debruijn32[32] = {
0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
};
if (sizeof(long) < 8) {
uint32_t y = x;
if (!y) {
y = x>>32;
return 32 + debruijn32[(y&-y)*0x076be629 >> 27];
return 32 + a_ctz_32(y);
}
return debruijn32[(y&-y)*0x076be629 >> 27];
return a_ctz_32(y);
}
return debruijn64[(x&-x)*0x022fdd63cc95386dull >> 58];
}
#endif
static inline int a_ctz_l(unsigned long x)
{
return (sizeof(long) < 8) ? a_ctz_32(x) : a_ctz_64(x);
}
#ifndef a_clz_64
#define a_clz_64 a_clz_64
static inline int a_clz_64(uint64_t x)
@ -298,17 +315,4 @@ static inline int a_clz_64(uint64_t x)
}
#endif
#ifndef a_ctz_l
#define a_ctz_l a_ctz_l
static inline int a_ctz_l(unsigned long x)
{
static const char debruijn32[32] = {
0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
};
if (sizeof(long) == 8) return a_ctz_64(x);
return debruijn32[(x&-x)*0x076be629 >> 27];
}
#endif
#endif