From: Dale Weiler Date: Sat, 23 Nov 2013 08:53:07 +0000 (-0500) Subject: A better mod implementation X-Git-Tag: xonotic-v0.8.0~86 X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=ae9d3d42cf95e3bdcdc891d0261d4b2461526056;p=xonotic%2Fgmqcc.git A better mod implementation --- diff --git a/intrin.c b/intrin.c index 20d82c6..d8442dc 100644 --- a/intrin.c +++ b/intrin.c @@ -204,49 +204,96 @@ static ast_expression *intrin_pow (intrin_t *intrin) { static ast_expression *intrin_mod(intrin_t *intrin) { /* - * float mod(float x, float y) { - * return x - y * floor(x / y); + * float mod(float a, float b) { + * float div = a / b; + * float sign = (div < 0.0f) ? -1 : 1; + * return a - b * sign * floor(sign * div); * } */ ast_value *value = NULL; ast_call *call = ast_call_new (intrin_ctx(intrin), intrin_func(intrin, "floor")); - ast_value *arg1 = ast_value_new(intrin_ctx(intrin), "x", TYPE_FLOAT); - ast_value *arg2 = ast_value_new(intrin_ctx(intrin), "y", TYPE_FLOAT); + ast_value *a = ast_value_new(intrin_ctx(intrin), "a", TYPE_FLOAT); + ast_value *b = ast_value_new(intrin_ctx(intrin), "b", TYPE_FLOAT); + ast_value *div = ast_value_new(intrin_ctx(intrin), "div", TYPE_FLOAT); + ast_value *sign = ast_value_new(intrin_ctx(intrin), "sign", TYPE_FLOAT); ast_block *body = ast_block_new(intrin_ctx(intrin)); ast_function *func = intrin_value(intrin, &value, "mod", TYPE_FLOAT); - /* floor(x/y) */ + vec_push(value->expression.params, a); + vec_push(value->expression.params, b); + + vec_push(body->locals, div); + vec_push(body->locals, sign); + + /* div = a / b; */ + vec_push(body->exprs, + (ast_expression*)ast_store_new( + intrin_ctx(intrin), + INSTR_STORE_F, + (ast_expression*)div, + (ast_expression*)ast_binary_new( + intrin_ctx(intrin), + INSTR_DIV_F, + (ast_expression*)a, + (ast_expression*)b + ) + ) + ); + + /* sign = (div < 0.0f) ? -1 : 1; */ + vec_push(body->exprs, + (ast_expression*)ast_store_new( + intrin_ctx(intrin), + INSTR_STORE_F, + (ast_expression*)sign, + (ast_expression*)ast_ternary_new( + intrin_ctx(intrin), + (ast_expression*)ast_binary_new( + intrin_ctx(intrin), + INSTR_LT, + (ast_expression*)div, + (ast_expression*)intrin->fold->imm_float[0] + ), + (ast_expression*)intrin->fold->imm_float[2], + (ast_expression*)intrin->fold->imm_float[1] + ) + ) + ); + + /* floor(sign * div) */ vec_push(call->params, - (ast_expression*)ast_binary_new ( + (ast_expression*)ast_binary_new( intrin_ctx(intrin), - INSTR_DIV_F, - (ast_expression*)arg1, - (ast_expression*)arg2 + INSTR_MUL_F, + (ast_expression*)sign, + (ast_expression*)div ) ); + /* return a - b * sign * */ vec_push(body->exprs, (ast_expression*)ast_return_new( intrin_ctx(intrin), (ast_expression*)ast_binary_new( intrin_ctx(intrin), INSTR_SUB_F, - (ast_expression*)arg1, + (ast_expression*)a, (ast_expression*)ast_binary_new( intrin_ctx(intrin), INSTR_MUL_F, - (ast_expression*)arg2, - (ast_expression*)call + (ast_expression*)b, + (ast_expression*)ast_binary_new( + intrin_ctx(intrin), + INSTR_MUL_F, + (ast_expression*)sign, + (ast_expression*)call + ) ) ) ) ); - vec_push(value->expression.params, arg1); /* float x (for param) */ - vec_push(value->expression.params, arg2); /* float y (for param) */ - - vec_push(func->blocks, body); /* {{{ body }}} */ - + vec_push(func->blocks, body); /* {{{ body }}} */ intrin_reg(intrin, value, func); return (ast_expression*)value; diff --git a/util.c b/util.c index 92e5f75..e46f80e 100644 --- a/util.c +++ b/util.c @@ -126,371 +126,73 @@ void util_endianswap(void *_data, size_t length, unsigned int typesize) { } /* - * Based On: - * Slicing-by-8 algorithms by Michael E. - * Kounavis and Frank L. Berry from Intel Corp. - * http://www.intel.com/technology/comms/perfnet/download/CRC_generators.pdf - * - * This code was made to be slightly less confusing with macros, which - * I suppose is somewhat ironic. - * - * The code had to be changed for non reflected on the output register - * since that's the method Quake uses. - * - * The code also had to be changed for CRC16, which is slightly harder - * since the CRC32 method in the original Intel paper used a different - * bit order convention. - * - * The table can be computed with: - * u16 table[8][256]; - * for (i = 0; i < 0x100; ++i) { - * u16 x = i << 8; - * for (j = 0; j < 8; j++) - * x = (x << 1) ^ ((x & 0x8000) ? 0x1021 : 0); - * table[0][i] = x; - * } - * for (i = 0; i < 0x100; ++i) { - * u16 c = (*table)[i]; - * for (j = 1; j < 8; ++j) - * table[j][i] = c = (*table)[c >> 8] ^ (c << 8)); - * } - * - * Notes about the table: - * - It's exactly 4K in size - * - 64 elements fit in a cache line - * - can do 8 iterations unrolled 8 times for free - * - The first 256 elements of the table are standard CRC16 table - */ -static const uint16_t util_crc16_table[8][256] = {{ - 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, - 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, - 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, - 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, - 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, - 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, - 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, - 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, - 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, - 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, - 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, - 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, - 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, - 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, - 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, - 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, - 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, - 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, - 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, - 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, - 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, - 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, - 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, - 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, - 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, - 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, - 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, - 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, - 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, - 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, - 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, - 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 -},{ - 0x0000, 0x3331, 0x6662, 0x5553, 0xCCC4, 0xFFF5, 0xAAA6, 0x9997, - 0x89A9, 0xBA98, 0xEFCB, 0xDCFA, 0x456D, 0x765C, 0x230F, 0x103E, - 0x0373, 0x3042, 0x6511, 0x5620, 0xCFB7, 0xFC86, 0xA9D5, 0x9AE4, - 0x8ADA, 0xB9EB, 0xECB8, 0xDF89, 0x461E, 0x752F, 0x207C, 0x134D, - 0x06E6, 0x35D7, 0x6084, 0x53B5, 0xCA22, 0xF913, 0xAC40, 0x9F71, - 0x8F4F, 0xBC7E, 0xE92D, 0xDA1C, 0x438B, 0x70BA, 0x25E9, 0x16D8, - 0x0595, 0x36A4, 0x63F7, 0x50C6, 0xC951, 0xFA60, 0xAF33, 0x9C02, - 0x8C3C, 0xBF0D, 0xEA5E, 0xD96F, 0x40F8, 0x73C9, 0x269A, 0x15AB, - 0x0DCC, 0x3EFD, 0x6BAE, 0x589F, 0xC108, 0xF239, 0xA76A, 0x945B, - 0x8465, 0xB754, 0xE207, 0xD136, 0x48A1, 0x7B90, 0x2EC3, 0x1DF2, - 0x0EBF, 0x3D8E, 0x68DD, 0x5BEC, 0xC27B, 0xF14A, 0xA419, 0x9728, - 0x8716, 0xB427, 0xE174, 0xD245, 0x4BD2, 0x78E3, 0x2DB0, 0x1E81, - 0x0B2A, 0x381B, 0x6D48, 0x5E79, 0xC7EE, 0xF4DF, 0xA18C, 0x92BD, - 0x8283, 0xB1B2, 0xE4E1, 0xD7D0, 0x4E47, 0x7D76, 0x2825, 0x1B14, - 0x0859, 0x3B68, 0x6E3B, 0x5D0A, 0xC49D, 0xF7AC, 0xA2FF, 0x91CE, - 0x81F0, 0xB2C1, 0xE792, 0xD4A3, 0x4D34, 0x7E05, 0x2B56, 0x1867, - 0x1B98, 0x28A9, 0x7DFA, 0x4ECB, 0xD75C, 0xE46D, 0xB13E, 0x820F, - 0x9231, 0xA100, 0xF453, 0xC762, 0x5EF5, 0x6DC4, 0x3897, 0x0BA6, - 0x18EB, 0x2BDA, 0x7E89, 0x4DB8, 0xD42F, 0xE71E, 0xB24D, 0x817C, - 0x9142, 0xA273, 0xF720, 0xC411, 0x5D86, 0x6EB7, 0x3BE4, 0x08D5, - 0x1D7E, 0x2E4F, 0x7B1C, 0x482D, 0xD1BA, 0xE28B, 0xB7D8, 0x84E9, - 0x94D7, 0xA7E6, 0xF2B5, 0xC184, 0x5813, 0x6B22, 0x3E71, 0x0D40, - 0x1E0D, 0x2D3C, 0x786F, 0x4B5E, 0xD2C9, 0xE1F8, 0xB4AB, 0x879A, - 0x97A4, 0xA495, 0xF1C6, 0xC2F7, 0x5B60, 0x6851, 0x3D02, 0x0E33, - 0x1654, 0x2565, 0x7036, 0x4307, 0xDA90, 0xE9A1, 0xBCF2, 0x8FC3, - 0x9FFD, 0xACCC, 0xF99F, 0xCAAE, 0x5339, 0x6008, 0x355B, 0x066A, - 0x1527, 0x2616, 0x7345, 0x4074, 0xD9E3, 0xEAD2, 0xBF81, 0x8CB0, - 0x9C8E, 0xAFBF, 0xFAEC, 0xC9DD, 0x504A, 0x637B, 0x3628, 0x0519, - 0x10B2, 0x2383, 0x76D0, 0x45E1, 0xDC76, 0xEF47, 0xBA14, 0x8925, - 0x991B, 0xAA2A, 0xFF79, 0xCC48, 0x55DF, 0x66EE, 0x33BD, 0x008C, - 0x13C1, 0x20F0, 0x75A3, 0x4692, 0xDF05, 0xEC34, 0xB967, 0x8A56, - 0x9A68, 0xA959, 0xFC0A, 0xCF3B, 0x56AC, 0x659D, 0x30CE, 0x03FF -},{ - 0x0000, 0x3730, 0x6E60, 0x5950, 0xDCC0, 0xEBF0, 0xB2A0, 0x8590, - 0xA9A1, 0x9E91, 0xC7C1, 0xF0F1, 0x7561, 0x4251, 0x1B01, 0x2C31, - 0x4363, 0x7453, 0x2D03, 0x1A33, 0x9FA3, 0xA893, 0xF1C3, 0xC6F3, - 0xEAC2, 0xDDF2, 0x84A2, 0xB392, 0x3602, 0x0132, 0x5862, 0x6F52, - 0x86C6, 0xB1F6, 0xE8A6, 0xDF96, 0x5A06, 0x6D36, 0x3466, 0x0356, - 0x2F67, 0x1857, 0x4107, 0x7637, 0xF3A7, 0xC497, 0x9DC7, 0xAAF7, - 0xC5A5, 0xF295, 0xABC5, 0x9CF5, 0x1965, 0x2E55, 0x7705, 0x4035, - 0x6C04, 0x5B34, 0x0264, 0x3554, 0xB0C4, 0x87F4, 0xDEA4, 0xE994, - 0x1DAD, 0x2A9D, 0x73CD, 0x44FD, 0xC16D, 0xF65D, 0xAF0D, 0x983D, - 0xB40C, 0x833C, 0xDA6C, 0xED5C, 0x68CC, 0x5FFC, 0x06AC, 0x319C, - 0x5ECE, 0x69FE, 0x30AE, 0x079E, 0x820E, 0xB53E, 0xEC6E, 0xDB5E, - 0xF76F, 0xC05F, 0x990F, 0xAE3F, 0x2BAF, 0x1C9F, 0x45CF, 0x72FF, - 0x9B6B, 0xAC5B, 0xF50B, 0xC23B, 0x47AB, 0x709B, 0x29CB, 0x1EFB, - 0x32CA, 0x05FA, 0x5CAA, 0x6B9A, 0xEE0A, 0xD93A, 0x806A, 0xB75A, - 0xD808, 0xEF38, 0xB668, 0x8158, 0x04C8, 0x33F8, 0x6AA8, 0x5D98, - 0x71A9, 0x4699, 0x1FC9, 0x28F9, 0xAD69, 0x9A59, 0xC309, 0xF439, - 0x3B5A, 0x0C6A, 0x553A, 0x620A, 0xE79A, 0xD0AA, 0x89FA, 0xBECA, - 0x92FB, 0xA5CB, 0xFC9B, 0xCBAB, 0x4E3B, 0x790B, 0x205B, 0x176B, - 0x7839, 0x4F09, 0x1659, 0x2169, 0xA4F9, 0x93C9, 0xCA99, 0xFDA9, - 0xD198, 0xE6A8, 0xBFF8, 0x88C8, 0x0D58, 0x3A68, 0x6338, 0x5408, - 0xBD9C, 0x8AAC, 0xD3FC, 0xE4CC, 0x615C, 0x566C, 0x0F3C, 0x380C, - 0x143D, 0x230D, 0x7A5D, 0x4D6D, 0xC8FD, 0xFFCD, 0xA69D, 0x91AD, - 0xFEFF, 0xC9CF, 0x909F, 0xA7AF, 0x223F, 0x150F, 0x4C5F, 0x7B6F, - 0x575E, 0x606E, 0x393E, 0x0E0E, 0x8B9E, 0xBCAE, 0xE5FE, 0xD2CE, - 0x26F7, 0x11C7, 0x4897, 0x7FA7, 0xFA37, 0xCD07, 0x9457, 0xA367, - 0x8F56, 0xB866, 0xE136, 0xD606, 0x5396, 0x64A6, 0x3DF6, 0x0AC6, - 0x6594, 0x52A4, 0x0BF4, 0x3CC4, 0xB954, 0x8E64, 0xD734, 0xE004, - 0xCC35, 0xFB05, 0xA255, 0x9565, 0x10F5, 0x27C5, 0x7E95, 0x49A5, - 0xA031, 0x9701, 0xCE51, 0xF961, 0x7CF1, 0x4BC1, 0x1291, 0x25A1, - 0x0990, 0x3EA0, 0x67F0, 0x50C0, 0xD550, 0xE260, 0xBB30, 0x8C00, - 0xE352, 0xD462, 0x8D32, 0xBA02, 0x3F92, 0x08A2, 0x51F2, 0x66C2, - 0x4AF3, 0x7DC3, 0x2493, 0x13A3, 0x9633, 0xA103, 0xF853, 0xCF63 -},{ - 0x0000, 0x76B4, 0xED68, 0x9BDC, 0xCAF1, 0xBC45, 0x2799, 0x512D, - 0x85C3, 0xF377, 0x68AB, 0x1E1F, 0x4F32, 0x3986, 0xA25A, 0xD4EE, - 0x1BA7, 0x6D13, 0xF6CF, 0x807B, 0xD156, 0xA7E2, 0x3C3E, 0x4A8A, - 0x9E64, 0xE8D0, 0x730C, 0x05B8, 0x5495, 0x2221, 0xB9FD, 0xCF49, - 0x374E, 0x41FA, 0xDA26, 0xAC92, 0xFDBF, 0x8B0B, 0x10D7, 0x6663, - 0xB28D, 0xC439, 0x5FE5, 0x2951, 0x787C, 0x0EC8, 0x9514, 0xE3A0, - 0x2CE9, 0x5A5D, 0xC181, 0xB735, 0xE618, 0x90AC, 0x0B70, 0x7DC4, - 0xA92A, 0xDF9E, 0x4442, 0x32F6, 0x63DB, 0x156F, 0x8EB3, 0xF807, - 0x6E9C, 0x1828, 0x83F4, 0xF540, 0xA46D, 0xD2D9, 0x4905, 0x3FB1, - 0xEB5F, 0x9DEB, 0x0637, 0x7083, 0x21AE, 0x571A, 0xCCC6, 0xBA72, - 0x753B, 0x038F, 0x9853, 0xEEE7, 0xBFCA, 0xC97E, 0x52A2, 0x2416, - 0xF0F8, 0x864C, 0x1D90, 0x6B24, 0x3A09, 0x4CBD, 0xD761, 0xA1D5, - 0x59D2, 0x2F66, 0xB4BA, 0xC20E, 0x9323, 0xE597, 0x7E4B, 0x08FF, - 0xDC11, 0xAAA5, 0x3179, 0x47CD, 0x16E0, 0x6054, 0xFB88, 0x8D3C, - 0x4275, 0x34C1, 0xAF1D, 0xD9A9, 0x8884, 0xFE30, 0x65EC, 0x1358, - 0xC7B6, 0xB102, 0x2ADE, 0x5C6A, 0x0D47, 0x7BF3, 0xE02F, 0x969B, - 0xDD38, 0xAB8C, 0x3050, 0x46E4, 0x17C9, 0x617D, 0xFAA1, 0x8C15, - 0x58FB, 0x2E4F, 0xB593, 0xC327, 0x920A, 0xE4BE, 0x7F62, 0x09D6, - 0xC69F, 0xB02B, 0x2BF7, 0x5D43, 0x0C6E, 0x7ADA, 0xE106, 0x97B2, - 0x435C, 0x35E8, 0xAE34, 0xD880, 0x89AD, 0xFF19, 0x64C5, 0x1271, - 0xEA76, 0x9CC2, 0x071E, 0x71AA, 0x2087, 0x5633, 0xCDEF, 0xBB5B, - 0x6FB5, 0x1901, 0x82DD, 0xF469, 0xA544, 0xD3F0, 0x482C, 0x3E98, - 0xF1D1, 0x8765, 0x1CB9, 0x6A0D, 0x3B20, 0x4D94, 0xD648, 0xA0FC, - 0x7412, 0x02A6, 0x997A, 0xEFCE, 0xBEE3, 0xC857, 0x538B, 0x253F, - 0xB3A4, 0xC510, 0x5ECC, 0x2878, 0x7955, 0x0FE1, 0x943D, 0xE289, - 0x3667, 0x40D3, 0xDB0F, 0xADBB, 0xFC96, 0x8A22, 0x11FE, 0x674A, - 0xA803, 0xDEB7, 0x456B, 0x33DF, 0x62F2, 0x1446, 0x8F9A, 0xF92E, - 0x2DC0, 0x5B74, 0xC0A8, 0xB61C, 0xE731, 0x9185, 0x0A59, 0x7CED, - 0x84EA, 0xF25E, 0x6982, 0x1F36, 0x4E1B, 0x38AF, 0xA373, 0xD5C7, - 0x0129, 0x779D, 0xEC41, 0x9AF5, 0xCBD8, 0xBD6C, 0x26B0, 0x5004, - 0x9F4D, 0xE9F9, 0x7225, 0x0491, 0x55BC, 0x2308, 0xB8D4, 0xCE60, - 0x1A8E, 0x6C3A, 0xF7E6, 0x8152, 0xD07F, 0xA6CB, 0x3D17, 0x4BA3 -},{ - 0x0000, 0xAA51, 0x4483, 0xEED2, 0x8906, 0x2357, 0xCD85, 0x67D4, - 0x022D, 0xA87C, 0x46AE, 0xECFF, 0x8B2B, 0x217A, 0xCFA8, 0x65F9, - 0x045A, 0xAE0B, 0x40D9, 0xEA88, 0x8D5C, 0x270D, 0xC9DF, 0x638E, - 0x0677, 0xAC26, 0x42F4, 0xE8A5, 0x8F71, 0x2520, 0xCBF2, 0x61A3, - 0x08B4, 0xA2E5, 0x4C37, 0xE666, 0x81B2, 0x2BE3, 0xC531, 0x6F60, - 0x0A99, 0xA0C8, 0x4E1A, 0xE44B, 0x839F, 0x29CE, 0xC71C, 0x6D4D, - 0x0CEE, 0xA6BF, 0x486D, 0xE23C, 0x85E8, 0x2FB9, 0xC16B, 0x6B3A, - 0x0EC3, 0xA492, 0x4A40, 0xE011, 0x87C5, 0x2D94, 0xC346, 0x6917, - 0x1168, 0xBB39, 0x55EB, 0xFFBA, 0x986E, 0x323F, 0xDCED, 0x76BC, - 0x1345, 0xB914, 0x57C6, 0xFD97, 0x9A43, 0x3012, 0xDEC0, 0x7491, - 0x1532, 0xBF63, 0x51B1, 0xFBE0, 0x9C34, 0x3665, 0xD8B7, 0x72E6, - 0x171F, 0xBD4E, 0x539C, 0xF9CD, 0x9E19, 0x3448, 0xDA9A, 0x70CB, - 0x19DC, 0xB38D, 0x5D5F, 0xF70E, 0x90DA, 0x3A8B, 0xD459, 0x7E08, - 0x1BF1, 0xB1A0, 0x5F72, 0xF523, 0x92F7, 0x38A6, 0xD674, 0x7C25, - 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0x3F56, 0x9507, 0x7BD5, 0xD184, 0xB650, 0x1C01, 0xF2D3, 0x5882, - 0x3D7B, 0x972A, 0x79F8, 0xD3A9, 0xB47D, 0x1E2C, 0xF0FE, 0x5AAF -},{ - 0x0000, 0x45A0, 0x8B40, 0xCEE0, 0x06A1, 0x4301, 0x8DE1, 0xC841, - 0x0D42, 0x48E2, 0x8602, 0xC3A2, 0x0BE3, 0x4E43, 0x80A3, 0xC503, - 0x1A84, 0x5F24, 0x91C4, 0xD464, 0x1C25, 0x5985, 0x9765, 0xD2C5, - 0x17C6, 0x5266, 0x9C86, 0xD926, 0x1167, 0x54C7, 0x9A27, 0xDF87, - 0x3508, 0x70A8, 0xBE48, 0xFBE8, 0x33A9, 0x7609, 0xB8E9, 0xFD49, - 0x384A, 0x7DEA, 0xB30A, 0xF6AA, 0x3EEB, 0x7B4B, 0xB5AB, 0xF00B, - 0x2F8C, 0x6A2C, 0xA4CC, 0xE16C, 0x292D, 0x6C8D, 0xA26D, 0xE7CD, - 0x22CE, 0x676E, 0xA98E, 0xEC2E, 0x246F, 0x61CF, 0xAF2F, 0xEA8F, - 0x6A10, 0x2FB0, 0xE150, 0xA4F0, 0x6CB1, 0x2911, 0xE7F1, 0xA251, - 0x6752, 0x22F2, 0xEC12, 0xA9B2, 0x61F3, 0x2453, 0xEAB3, 0xAF13, - 0x7094, 0x3534, 0xFBD4, 0xBE74, 0x7635, 0x3395, 0xFD75, 0xB8D5, - 0x7DD6, 0x3876, 0xF696, 0xB336, 0x7B77, 0x3ED7, 0xF037, 0xB597, - 0x5F18, 0x1AB8, 0xD458, 0x91F8, 0x59B9, 0x1C19, 0xD2F9, 0x9759, - 0x525A, 0x17FA, 0xD91A, 0x9CBA, 0x54FB, 0x115B, 0xDFBB, 0x9A1B, - 0x459C, 0x003C, 0xCEDC, 0x8B7C, 0x433D, 0x069D, 0xC87D, 0x8DDD, - 0x48DE, 0x0D7E, 0xC39E, 0x863E, 0x4E7F, 0x0BDF, 0xC53F, 0x809F, - 0xD420, 0x9180, 0x5F60, 0x1AC0, 0xD281, 0x9721, 0x59C1, 0x1C61, - 0xD962, 0x9CC2, 0x5222, 0x1782, 0xDFC3, 0x9A63, 0x5483, 0x1123, - 0xCEA4, 0x8B04, 0x45E4, 0x0044, 0xC805, 0x8DA5, 0x4345, 0x06E5, - 0xC3E6, 0x8646, 0x48A6, 0x0D06, 0xC547, 0x80E7, 0x4E07, 0x0BA7, - 0xE128, 0xA488, 0x6A68, 0x2FC8, 0xE789, 0xA229, 0x6CC9, 0x2969, - 0xEC6A, 0xA9CA, 0x672A, 0x228A, 0xEACB, 0xAF6B, 0x618B, 0x242B, - 0xFBAC, 0xBE0C, 0x70EC, 0x354C, 0xFD0D, 0xB8AD, 0x764D, 0x33ED, - 0xF6EE, 0xB34E, 0x7DAE, 0x380E, 0xF04F, 0xB5EF, 0x7B0F, 0x3EAF, - 0xBE30, 0xFB90, 0x3570, 0x70D0, 0xB891, 0xFD31, 0x33D1, 0x7671, - 0xB372, 0xF6D2, 0x3832, 0x7D92, 0xB5D3, 0xF073, 0x3E93, 0x7B33, - 0xA4B4, 0xE114, 0x2FF4, 0x6A54, 0xA215, 0xE7B5, 0x2955, 0x6CF5, - 0xA9F6, 0xEC56, 0x22B6, 0x6716, 0xAF57, 0xEAF7, 0x2417, 0x61B7, - 0x8B38, 0xCE98, 0x0078, 0x45D8, 0x8D99, 0xC839, 0x06D9, 0x4379, - 0x867A, 0xC3DA, 0x0D3A, 0x489A, 0x80DB, 0xC57B, 0x0B9B, 0x4E3B, - 0x91BC, 0xD41C, 0x1AFC, 0x5F5C, 0x971D, 0xD2BD, 0x1C5D, 0x59FD, - 0x9CFE, 0xD95E, 0x17BE, 0x521E, 0x9A5F, 0xDFFF, 0x111F, 0x54BF -},{ - 0x0000, 0xB861, 0x60E3, 0xD882, 0xC1C6, 0x79A7, 0xA125, 0x1944, - 0x93AD, 0x2BCC, 0xF34E, 0x4B2F, 0x526B, 0xEA0A, 0x3288, 0x8AE9, - 0x377B, 0x8F1A, 0x5798, 0xEFF9, 0xF6BD, 0x4EDC, 0x965E, 0x2E3F, - 0xA4D6, 0x1CB7, 0xC435, 0x7C54, 0x6510, 0xDD71, 0x05F3, 0xBD92, - 0x6EF6, 0xD697, 0x0E15, 0xB674, 0xAF30, 0x1751, 0xCFD3, 0x77B2, - 0xFD5B, 0x453A, 0x9DB8, 0x25D9, 0x3C9D, 0x84FC, 0x5C7E, 0xE41F, - 0x598D, 0xE1EC, 0x396E, 0x810F, 0x984B, 0x202A, 0xF8A8, 0x40C9, - 0xCA20, 0x7241, 0xAAC3, 0x12A2, 0x0BE6, 0xB387, 0x6B05, 0xD364, - 0xDDEC, 0x658D, 0xBD0F, 0x056E, 0x1C2A, 0xA44B, 0x7CC9, 0xC4A8, - 0x4E41, 0xF620, 0x2EA2, 0x96C3, 0x8F87, 0x37E6, 0xEF64, 0x5705, - 0xEA97, 0x52F6, 0x8A74, 0x3215, 0x2B51, 0x9330, 0x4BB2, 0xF3D3, - 0x793A, 0xC15B, 0x19D9, 0xA1B8, 0xB8FC, 0x009D, 0xD81F, 0x607E, - 0xB31A, 0x0B7B, 0xD3F9, 0x6B98, 0x72DC, 0xCABD, 0x123F, 0xAA5E, - 0x20B7, 0x98D6, 0x4054, 0xF835, 0xE171, 0x5910, 0x8192, 0x39F3, - 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0xB00C, 0xF7DF, 0x3FAA, 0x7879, 0xBF61, 0xF8B2, 0x30C7, 0x7714, - 0xAED6, 0xE905, 0x2170, 0x66A3, 0xA1BB, 0xE668, 0x2E1D, 0x69CE, - 0xFD81, 0xBA52, 0x7227, 0x35F4, 0xF2EC, 0xB53F, 0x7D4A, 0x3A99, - 0xE35B, 0xA488, 0x6CFD, 0x2B2E, 0xEC36, 0xABE5, 0x6390, 0x2443, - 0xC035, 0x87E6, 0x4F93, 0x0840, 0xCF58, 0x888B, 0x40FE, 0x072D, - 0xDEEF, 0x993C, 0x5149, 0x169A, 0xD182, 0x9651, 0x5E24, 0x19F7, - 0x86E9, 0xC13A, 0x094F, 0x4E9C, 0x8984, 0xCE57, 0x0622, 0x41F1, - 0x9833, 0xDFE0, 0x1795, 0x5046, 0x975E, 0xD08D, 0x18F8, 0x5F2B, - 0xBB5D, 0xFC8E, 0x34FB, 0x7328, 0xB430, 0xF3E3, 0x3B96, 0x7C45, - 0xA587, 0xE254, 0x2A21, 0x6DF2, 0xAAEA, 0xED39, 0x254C, 0x629F, - 0x0B51, 0x4C82, 0x84F7, 0xC324, 0x043C, 0x43EF, 0x8B9A, 0xCC49, - 0x158B, 0x5258, 0x9A2D, 0xDDFE, 0x1AE6, 0x5D35, 0x9540, 0xD293, - 0x36E5, 0x7136, 0xB943, 0xFE90, 0x3988, 0x7E5B, 0xB62E, 0xF1FD, - 0x283F, 0x6FEC, 0xA799, 0xE04A, 0x2752, 0x6081, 0xA8F4, 0xEF27, - 0x7039, 0x37EA, 0xFF9F, 0xB84C, 0x7F54, 0x3887, 0xF0F2, 0xB721, - 0x6EE3, 0x2930, 0xE145, 0xA696, 0x618E, 0x265D, 0xEE28, 0xA9FB, - 0x4D8D, 0x0A5E, 0xC22B, 0x85F8, 0x42E0, 0x0533, 0xCD46, 0x8A95, - 0x5357, 0x1484, 0xDCF1, 0x9B22, 0x5C3A, 0x1BE9, 0xD39C, 0x944F -}}; +* CRC algorithms vary in the width of the polynomial, the value of said polynomial, +* the initial value used for the register, weather the bits of each byte are reflected +* before being processed, weather the algorithm itself feeds input bytes through the +* register or XORs them with a byte from one end and then straight into the table, as +* well as (but not limited to the idea of reflected versions) where the final register +* value becomes reversed, and finally weather the value itself is used to XOR the final +* register value. AS such you can already imagine how painfully annoying CRCs are, +* of course we stand to target Quake, which expects it's certain set of rules for proper +* calculation of a CRC. +* +* In most traditional CRC algorithms on uses a reflected table driven method where a value +* or register is reflected if it's bits are swapped around it's center. For example: +* take the bits 0101 is the 4-bit reflection of 1010, and respectfully 0011 would be the +* reflection of 1100. Quake however expects a NON-Reflected CRC on the output, but still +* requires a final XOR on the values (0xFFFF and 0x0000) this is a standard CCITT CRC-16 +* which I respectfully as a programmer don't agree with. +* +* So now you know what we target, and why we target it, despite how unsettling it may seem +* but those are what Quake seems to request. +*/ + +static const uint16_t util_crc16_table[] = { + 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, + 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210, + 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, + 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401, + 0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, + 0xF5CF, 0xC5AC, 0xD58D, 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, + 0x5695, 0x46B4, 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, + 0xC7BC, 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, + 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, 0x5AF5, + 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC, + 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, 0x6CA6, 0x7C87, 0x4CE4, + 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, + 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, + 0x2E32, 0x1E51, 0x0E70, 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, + 0x9F59, 0x8F78, 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, + 0xE16F, 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, + 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, 0x02B1, + 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, 0xB5EA, 0xA5CB, + 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, 0x34E2, 0x24C3, 0x14A0, + 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xA7DB, 0xB7FA, 0x8799, 0x97B8, + 0xE75F, 0xF77E, 0xC71D, 0xD73C, 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, + 0x7676, 0x4615, 0x5634, 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, + 0xB98A, 0xA9AB, 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, + 0x28A3, 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, + 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, 0xFD2E, + 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, 0x7C26, 0x6C07, + 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, 0xEF1F, 0xFF3E, 0xCF5D, + 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, 0x6E17, 0x7E36, 0x4E55, 0x5E74, + 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 +}; +/* Non - Reflected */ uint16_t util_crc16(uint16_t current, const char *k, size_t len) { - /* keep in register for fast cascade */ register uint16_t h = current; - - /* don't load twice */ - uint8_t *GMQCC_RESTRICT data = (uint8_t *GMQCC_RESTRICT)k; - size_t n; - - #define SELECT_BULK(X, MOD) util_crc16_table[(X)][data[7-(X)] ^ (MOD)] - #define SELECT_DATA(X) util_crc16_table[(X)][data[7-(X)]] - - for (n = len / 8; n; --n) { - h = SELECT_BULK(7, (h >> 8)) ^ - SELECT_BULK(6, (h & 0xFF)) ^ - SELECT_DATA(5) ^ - SELECT_DATA(4) ^ - SELECT_DATA(3) ^ - SELECT_DATA(2) ^ - SELECT_DATA(1); - data += 8; - } - - /* deal with the rest with the byte method */ - for (n &= 7; n; --n) - h = (uint16_t)(h << 8) ^ (*util_crc16_table)[(h >> 8) ^ *data++]; - + for (; len; --len, ++k) + h = util_crc16_table[(h>>8)^((unsigned char)*k)]^(h<<8); return h; } -/* - * The table above can be created with the following utility. Which - * just builds the slices and the C array as well. - */ +/* Reflective Variation (for reference) */ #if 0 -#include -#include -#include -/* compile with cc -std=c99 */ -int main(void) { - uint16_t tab[8][256]; - for (unsigned i = 0; i < 0x100; ++i) { - uint16_t x = i << 8; - for (int j = 0; j < 8; ++j) - x = (x << 1) ^ ((x & 0x8000) ? 0x1021 : 0); - tab[0][i] = x; - } - for (unsigned i = 0; i < 0x100; ++i) { - uint16_t c = tab[0][i]; - for (unsigned j = 1; j < 8; ++j) { - c = tab[0][c >> 8] ^ (c << 8); - tab[j][i] = c; - } - } - printf("static const uint16_t util_crc16_table[8][256] = {"); - for (int i = 0; i < 8; ++i) { - printf("{\n"); - for (int j = 0; j < 0x100; ++j) { - printf((j & 7) ? " " : " "); - printf((j != 0x100-1) ? "0x%04X," : "0x%04X", tab[i][j]); - if ((j & 7) == 7) - printf("\n"); - } - printf((i != 7) ? "}," : "}"); - } - printf("};\n"); +uint16_t util_crc16(const char *k, int len, const short clamp) { + register uint16_t h= (uint16_t)0xFFFFFFFF; + for (; len; --len, ++k) + h = util_crc16_table[(h^((unsigned char)*k))&0xFF]^(h>>8); + return (~h)%clamp; } #endif