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Nathan Giddings
2023-01-09 01:54:03 -06:00
commit d347b81e72
14 changed files with 856 additions and 0 deletions
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69
include/util.h Normal file
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#ifndef _LIBMALLOC_UTIL_H
#define _LIBMALLOC_UTIL_H
static inline int ilog2(unsigned int x)
{
#if defined __GNUC__
if(x <= 1)
return 0;
return 32 - __builtin_clz(x - 1);
#else
static const int table[32] = {
0, 9, 1, 10, 13, 21, 2, 29,
11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7,
19, 27, 23, 6, 26, 5, 4, 31};
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
return table[(x * 0x07C4ACDD) >> 27];
#endif
}
static inline int llog2(unsigned long x)
{
#if (defined __GNUC__) && (__SIZEOF_LONG__ == 4)
if(x <= 1)
return 0;
return 32 - __builtin_clzl(x - 1);
#elif (defined __GNUC__) && (__SIZEOF_LONG__ == 8)
if(x <= 1)
return 0;
return 64 - __builtin_clzl(x - 1);
#elif __SIZEOF_LONG__ == 8
static const int table[64] = {
0, 58, 1, 59, 47, 53, 2, 60, 39, 48, 27, 54, 33, 42, 3, 61,
51, 37, 40, 49, 18, 28, 20, 55, 30, 34, 11, 43, 14, 22, 4, 62,
57, 46, 52, 38, 26, 32, 41, 50, 36, 17, 19, 29, 10, 13, 21, 56,
45, 25, 31, 35, 16, 9, 12, 44, 24, 15, 8, 23, 7, 6, 5, 63};
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
x |= x >> 32;
return table[(x * 0x03f6eaf2cd271461) >> 58];
#else
static const int table[32] = {
0, 9, 1, 10, 13, 21, 2, 29,
11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7,
19, 27, 23, 6, 26, 5, 4, 31};
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
return table[(x * 0x07C4ACDD) >> 27];
#endif
}
#endif