1 /* 2 * Utility compute operations used by translated code. 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * Copyright (c) 2007 Aurelien Jarno 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 * THE SOFTWARE. 24 */ 25 26 #include <stdlib.h> 27 #include <stdint.h> 28 #include "qemu/host-utils.h" 29 30 /* Long integer helpers */ 31 #ifndef CONFIG_INT128 32 static inline void mul64(uint64_t *plow, uint64_t *phigh, 33 uint64_t a, uint64_t b) 34 { 35 typedef union { 36 uint64_t ll; 37 struct { 38 #ifdef HOST_WORDS_BIGENDIAN 39 uint32_t high, low; 40 #else 41 uint32_t low, high; 42 #endif 43 } l; 44 } LL; 45 LL rl, rm, rn, rh, a0, b0; 46 uint64_t c; 47 48 a0.ll = a; 49 b0.ll = b; 50 51 rl.ll = (uint64_t)a0.l.low * b0.l.low; 52 rm.ll = (uint64_t)a0.l.low * b0.l.high; 53 rn.ll = (uint64_t)a0.l.high * b0.l.low; 54 rh.ll = (uint64_t)a0.l.high * b0.l.high; 55 56 c = (uint64_t)rl.l.high + rm.l.low + rn.l.low; 57 rl.l.high = c; 58 c >>= 32; 59 c = c + rm.l.high + rn.l.high + rh.l.low; 60 rh.l.low = c; 61 rh.l.high += (uint32_t)(c >> 32); 62 63 *plow = rl.ll; 64 *phigh = rh.ll; 65 } 66 67 /* Unsigned 64x64 -> 128 multiplication */ 68 void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b) 69 { 70 mul64(plow, phigh, a, b); 71 } 72 73 /* Signed 64x64 -> 128 multiplication */ 74 void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b) 75 { 76 uint64_t rh; 77 78 mul64(plow, &rh, a, b); 79 80 /* Adjust for signs. */ 81 if (b < 0) { 82 rh -= a; 83 } 84 if (a < 0) { 85 rh -= b; 86 } 87 *phigh = rh; 88 } 89 90 /* Unsigned 128x64 division. Returns 1 if overflow (divide by zero or */ 91 /* quotient exceeds 64 bits). Otherwise returns quotient via plow and */ 92 /* remainder via phigh. */ 93 int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor) 94 { 95 uint64_t dhi = *phigh; 96 uint64_t dlo = *plow; 97 unsigned i; 98 uint64_t carry = 0; 99 100 if (divisor == 0) { 101 return 1; 102 } else if (dhi == 0) { 103 *plow = dlo / divisor; 104 *phigh = dlo % divisor; 105 return 0; 106 } else if (dhi > divisor) { 107 return 1; 108 } else { 109 110 for (i = 0; i < 64; i++) { 111 carry = dhi >> 63; 112 dhi = (dhi << 1) | (dlo >> 63); 113 if (carry || (dhi >= divisor)) { 114 dhi -= divisor; 115 carry = 1; 116 } else { 117 carry = 0; 118 } 119 dlo = (dlo << 1) | carry; 120 } 121 122 *plow = dlo; 123 *phigh = dhi; 124 return 0; 125 } 126 } 127 128 int divs128(int64_t *plow, int64_t *phigh, int64_t divisor) 129 { 130 int sgn_dvdnd = *phigh < 0; 131 int sgn_divsr = divisor < 0; 132 int overflow = 0; 133 134 if (sgn_dvdnd) { 135 *plow = ~(*plow); 136 *phigh = ~(*phigh); 137 if (*plow == (int64_t)-1) { 138 *plow = 0; 139 (*phigh)++; 140 } else { 141 (*plow)++; 142 } 143 } 144 145 if (sgn_divsr) { 146 divisor = 0 - divisor; 147 } 148 149 overflow = divu128((uint64_t *)plow, (uint64_t *)phigh, (uint64_t)divisor); 150 151 if (sgn_dvdnd ^ sgn_divsr) { 152 *plow = 0 - *plow; 153 } 154 155 if (!overflow) { 156 if ((*plow < 0) ^ (sgn_dvdnd ^ sgn_divsr)) { 157 overflow = 1; 158 } 159 } 160 161 return overflow; 162 } 163 164 #endif /* !CONFIG_INT128 */ 165