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fix generic ctz/clz

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daanx 2024-12-09 20:45:22 -08:00
parent c8607a8d01
commit ed31847112
1 changed files with 34 additions and 23 deletions
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57
include/mimalloc/internal.h
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@ -873,16 +873,18 @@ static inline size_t mi_ctz(uintptr_t x) {
} }
#else #else
static inline size_t mi_ctz32(uint32_t x) {
static inline size_t mi_ctz_generic32(uint32_t x) {
// de Bruijn multiplication, see <http://supertech.csail.mit.edu/papers/debruijn.pdf> // de Bruijn multiplication, see <http://supertech.csail.mit.edu/papers/debruijn.pdf>
static const unsigned char debruijn[32] = { static const uint8_t debruijn[32] = {
0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
}; };
if (x==0) return 32; if (x==0) return 32;
return debruijn[((x & -(int32_t)x) * 0x077CB531UL) >> 27]; return debruijn[(uint32_t)((x & -(int32_t)x) * (uint32_t)(0x077CB531U)) >> 27];
} }
static inline size_t mi_clz32(uint32_t x) {
static inline size_t mi_clz_generic32(uint32_t x) {
// de Bruijn multiplication, see <http://supertech.csail.mit.edu/papers/debruijn.pdf> // de Bruijn multiplication, see <http://supertech.csail.mit.edu/papers/debruijn.pdf>
static const uint8_t debruijn[32] = { static const uint8_t debruijn[32] = {
31, 22, 30, 21, 18, 10, 29, 2, 20, 17, 15, 13, 9, 6, 28, 1, 31, 22, 30, 21, 18, 10, 29, 2, 20, 17, 15, 13, 9, 6, 28, 1,
@ -894,28 +896,37 @@ static inline size_t mi_clz32(uint32_t x) {
x |= x >> 4; x |= x >> 4;
x |= x >> 8; x |= x >> 8;
x |= x >> 16; x |= x >> 16;
return debruijn[(uint32_t)(x * 0x07C4ACDDUL) >> 27]; return debruijn[(uint32_t)(x * (uint32_t)(0x07C4ACDDU)) >> 27];
} }
static inline size_t mi_clz(uintptr_t x) { static inline size_t mi_ctz(size_t x) {
if (x==0) return MI_INTPTR_BITS; if (x==0) return MI_SIZE_BITS;
#if (MI_INTPTR_BITS <= 32) #if (MI_SIZE_BITS <= 32)
return mi_clz32((uint32_t)x); return mi_ctz_generic32((uint32_t)x);
#else #else
size_t count = mi_clz32((uint32_t)(x >> 32)); const uint32_t lo = (uint32_t)x;
if (count < 32) return count; if (lo != 0) {
return (32 + mi_clz32((uint32_t)x)); return mi_ctz_generic32(lo);
#endif }
else {
return (32 + mi_ctz_generic32((uint32_t)(x>>32)));
}
#endif
} }
static inline size_t mi_ctz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS; static inline size_t mi_clz(size_t x) {
#if (MI_INTPTR_BITS <= 32) if (x==0) return MI_SIZE_BITS;
return mi_ctz32((uint32_t)x); #if (MI_SIZE_BITS <= 32)
#else return mi_clz_generic32((uint32_t)x);
size_t count = mi_ctz32((uint32_t)x); #else
if (count < 32) return count; const uint32_t hi = (uint32_t)(x>>32);
return (32 + mi_ctz32((uint32_t)(x>>32))); if (hi != 0) {
#endif return mi_clz_generic32(hi);
}
else {
return 32 + mi_clz_generic32((uint32_t)x);
}
#endif
} }
#endif #endif