Author: Dann Corbit
Date: 13:44:26 01/22/03
Go up one level in this thread
#include <cstdio> #include <cstring> #include <climits> #include <cassert> typedef unsigned __int64 Bitboard; static const unsigned char revchr[] = { 0, 128, 64, 192, 32, 160, 96, 224, 16, 144, 80, 208, 48, 176, 112, 240, 8, 136, 72, 200, 40, 168, 104, 232, 24, 152, 88, 216, 56, 184, 120, 248, 4, 132, 68, 196, 36, 164, 100, 228, 20, 148, 84, 212, 52, 180, 116, 244, 12, 140, 76, 204, 44, 172, 108, 236, 28, 156, 92, 220, 60, 188, 124, 252, 2, 130, 66, 194, 34, 162, 98, 226, 18, 146, 82, 210, 50, 178, 114, 242, 10, 138, 74, 202, 42, 170, 106, 234, 26, 154, 90, 218, 58, 186, 122, 250, 6, 134, 70, 198, 38, 166, 102, 230, 22, 150, 86, 214, 54, 182, 118, 246, 14, 142, 78, 206, 46, 174, 110, 238, 30, 158, 94, 222, 62, 190, 126, 254, 1, 129, 65, 193, 33, 161, 97, 225, 17, 145, 81, 209, 49, 177, 113, 241, 9, 137, 73, 201, 41, 169, 105, 233, 25, 153, 89, 217, 57, 185, 121, 249, 5, 133, 69, 197, 37, 165, 101, 229, 21, 149, 85, 213, 53, 181, 117, 245, 13, 141, 77, 205, 45, 173, 109, 237, 29, 157, 93, 221, 61, 189, 125, 253, 3, 131, 67, 195, 35, 163, 99, 227, 19, 147, 83, 211, 51, 179, 115, 243, 11, 139, 75, 203, 43, 171, 107, 235, 27, 155, 91, 219, 59, 187, 123, 251, 7, 135, 71, 199, 39, 167, 103, 231, 23, 151, 87, 215, 55, 183, 119, 247, 15, 143, 79, 207, 47, 175, 111, 239, 31, 159, 95, 223, 63, 191, 127, 255 }; unsigned char swapNibble(unsigned char test) { unsigned char loMask = 0x0F; static const unsigned char rev[] = {0x0, 0x8, 0x4, 0xC, 0x2, 0xA, 0x6, 0xE, 0x1, 0x9, 0x5, 0xD, 0x3, 0xB, 0x7, 0xF}; assert(CHAR_BIT == 8); return (rev[test & loMask] << 4) | rev[(test >> 4) & loMask]; } unsigned char revbits_8(unsigned char n) { int i = 8; unsigned char m = -1; assert(CHAR_BIT == 8); while (i /= 2) m ^= m << i, n = n >> i & m | (n & m) << i; return n; } /* ** Separare tasks into basic jobs to be performed. */ unsigned char *reverse_64_a(void *v) { unsigned char *s = (unsigned char *) v; unsigned char *last; unsigned char temp; size_t lgh = 8; last = s + lgh; while (last-- > s) { temp = revchr[*s]; *s++ = revchr[*last]; *last = temp; } return s; } /* ** Separare tasks into basic jobs to be performed. */ unsigned char *reverse_64_b(void *v) { unsigned char *s = (unsigned char *) v; unsigned char *last; unsigned char temp; size_t lgh = 8; assert(CHAR_BIT == 8); last = s + lgh; while (last-- > s) { temp = swapNibble(*s); *s++ = swapNibble(*last); *last = temp; } return s; } /* ** Separare tasks into basic jobs to be performed. */ unsigned char *reverse_64_c(void *v) { unsigned char *s = (unsigned char *) v; unsigned char *last; unsigned char temp; size_t lgh = 8; assert(CHAR_BIT == 8); last = s + lgh; while (last-- > s) { temp = revbits_8(*s); *s++ = revbits_8(*last); *last = temp; } return s; } /* Some pretty patters for bit reversal of 32 bit integers: a = ((a << 16) & 0xFFFF0000) | ((a >> 16) & 0x0000FFFF); a = ((a << 8) & 0xFF00FF00) | ((a >> 8) & 0x00FF00FF); a = ((a << 4) & 0xF0F0F0F0) | ((a >> 4) & 0x0F0F0F0F); a = ((a << 2) & 0xCCCCCCCC) | ((a >> 2) & 0x33333333); a = ((a << 1) & 0xAAAAAAAA) | ((a >> 1) & 0x55555555); n = ((n >> 1) & 0x55555555) | ((n << 1) & 0xaaaaaaaa); n = ((n >> 2) & 0x33333333) | ((n << 2) & 0xcccccccc); n = ((n >> 4) & 0x0f0f0f0f) | ((n << 4) & 0xf0f0f0f0); n = ((n >> 8) & 0x00ff00ff) | ((n << 8) & 0xff00ff00); n = ((n >> 16) & 0x0000ffff) | ((n << 16) & 0xffff0000); */ Bitboard breverse0(Bitboard n) { Bitboard r = 0, j = 1, m = n; while (r = 2 * r + m % 2, j *= 2) m /= 2; return r; } Bitboard breverse1(Bitboard n) { Bitboard r = 0, j = 1; while (r = r * 2 | n & 1, j *= 2) n >>= 1; return r; } Bitboard breverse2(Bitboard n) { Bitboard r = 0, j = 1; while (r = 2 * r | (n & j) / j, j *= 2); return r; } Bitboard breverse3(Bitboard v) { Bitboard r = 0, q = -1; while (q) { r = (r << 1) | (v & 1); v >>= 1; q >>= 1; } return r; } Bitboard breverse4(Bitboard v) { Bitboard r = 0, q = -1; while (q) { r = (r << 1) | (v & 1); v >>= 1; q >>= 1; } return r; } Bitboard breverse5(Bitboard n) { int i = 64; Bitboard m = -1; while (i /= 2) m ^= m << i, n = n >> i & m | (n & m) << i; return n; } #include <cstdio> int main(void) { Bitboard a, b; b = 0xffffffffffffffffui64; a = breverse0(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse0 fails."); a = breverse1(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse1 fails."); a = breverse2(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse2 fails."); a = breverse3(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse3 fails."); a = breverse4(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse4 fails."); a = breverse5(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse5 fails."); a = breverse5(b); if (a != b || a != 0xffffffffffffffffui64) puts("breverse5 fails."); reverse_64_a((void *)&b); if (a != b || a != 0xffffffffffffffffui64) puts("reverse_64_a fails."); reverse_64_b((void *)&b); if (a != b || a != 0xffffffffffffffffui64) puts("reverse_64_b fails."); reverse_64_c((void *)&b); if (a != b || a != 0xffffffffffffffffui64) puts("reverse_64_c fails."); b = 0xfafafafafafafafaui64; a = breverse0(b); b = breverse0(a); if (a != breverse0(b) || b != 0xfafafafafafafafaui64) puts("breverse0 fails."); b = 0xfafafafafafafafaui64; a = breverse1(b); b = breverse1(a); if (a != breverse1(b) || b != 0xfafafafafafafafaui64) puts("breverse1 fails."); b = 0xfafafafafafafafaui64; a = breverse2(b); b = breverse2(a); if (a != breverse2(b) || b != 0xfafafafafafafafaui64) puts("breverse2 fails."); b = 0xfafafafafafafafaui64; a = breverse3(b); b = breverse3(a); if (a != breverse3(b) || b != 0xfafafafafafafafaui64) puts("breverse3 fails."); b = 0xfafafafafafafafaui64; a = breverse4(b); b = breverse4(a); if (a != breverse4(b) || b != 0xfafafafafafafafaui64) puts("breverse4 fails."); a = b = 0xfafafafafafafafaui64; reverse_64_a((void *)&b); reverse_64_a((void *)&b); if (a != b || b != 0xfafafafafafafafaui64) puts("reverse_64_a fails."); b = 0xfafafafafafafafaui64; reverse_64_b((void *)&b); reverse_64_b((void *)&b); if (a != b || b != 0xfafafafafafafafaui64) puts("reverse_64_b fails."); b = 0xfafafafafafafafaui64; reverse_64_c((void *)&b); reverse_64_c((void *)&b); if (a != b || b != 0xfafafafafafafafaui64) puts("reverse_64_c fails."); return 0; }
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