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 "qemu/osdep.h" 27 #include "qemu/host-utils.h" 28 29 #ifndef CONFIG_INT128 30 /* Long integer helpers */ 31 static inline void mul64(uint64_t *plow, uint64_t *phigh, 32 uint64_t a, uint64_t b) 33 { 34 typedef union { 35 uint64_t ll; 36 struct { 37 #ifdef HOST_WORDS_BIGENDIAN 38 uint32_t high, low; 39 #else 40 uint32_t low, high; 41 #endif 42 } l; 43 } LL; 44 LL rl, rm, rn, rh, a0, b0; 45 uint64_t c; 46 47 a0.ll = a; 48 b0.ll = b; 49 50 rl.ll = (uint64_t)a0.l.low * b0.l.low; 51 rm.ll = (uint64_t)a0.l.low * b0.l.high; 52 rn.ll = (uint64_t)a0.l.high * b0.l.low; 53 rh.ll = (uint64_t)a0.l.high * b0.l.high; 54 55 c = (uint64_t)rl.l.high + rm.l.low + rn.l.low; 56 rl.l.high = c; 57 c >>= 32; 58 c = c + rm.l.high + rn.l.high + rh.l.low; 59 rh.l.low = c; 60 rh.l.high += (uint32_t)(c >> 32); 61 62 *plow = rl.ll; 63 *phigh = rh.ll; 64 } 65 66 /* Unsigned 64x64 -> 128 multiplication */ 67 void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b) 68 { 69 mul64(plow, phigh, a, b); 70 } 71 72 /* Signed 64x64 -> 128 multiplication */ 73 void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b) 74 { 75 uint64_t rh; 76 77 mul64(plow, &rh, a, b); 78 79 /* Adjust for signs. */ 80 if (b < 0) { 81 rh -= a; 82 } 83 if (a < 0) { 84 rh -= b; 85 } 86 *phigh = rh; 87 } 88 89 /* Unsigned 128x64 division. Returns 1 if overflow (divide by zero or */ 90 /* quotient exceeds 64 bits). Otherwise returns quotient via plow and */ 91 /* remainder via phigh. */ 92 int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor) 93 { 94 uint64_t dhi = *phigh; 95 uint64_t dlo = *plow; 96 unsigned i; 97 uint64_t carry = 0; 98 99 if (divisor == 0) { 100 return 1; 101 } else if (dhi == 0) { 102 *plow = dlo / divisor; 103 *phigh = dlo % divisor; 104 return 0; 105 } else if (dhi > divisor) { 106 return 1; 107 } else { 108 109 for (i = 0; i < 64; i++) { 110 carry = dhi >> 63; 111 dhi = (dhi << 1) | (dlo >> 63); 112 if (carry || (dhi >= divisor)) { 113 dhi -= divisor; 114 carry = 1; 115 } else { 116 carry = 0; 117 } 118 dlo = (dlo << 1) | carry; 119 } 120 121 *plow = dlo; 122 *phigh = dhi; 123 return 0; 124 } 125 } 126 127 int divs128(int64_t *plow, int64_t *phigh, int64_t divisor) 128 { 129 int sgn_dvdnd = *phigh < 0; 130 int sgn_divsr = divisor < 0; 131 int overflow = 0; 132 133 if (sgn_dvdnd) { 134 *plow = ~(*plow); 135 *phigh = ~(*phigh); 136 if (*plow == (int64_t)-1) { 137 *plow = 0; 138 (*phigh)++; 139 } else { 140 (*plow)++; 141 } 142 } 143 144 if (sgn_divsr) { 145 divisor = 0 - divisor; 146 } 147 148 overflow = divu128((uint64_t *)plow, (uint64_t *)phigh, (uint64_t)divisor); 149 150 if (sgn_dvdnd ^ sgn_divsr) { 151 *plow = 0 - *plow; 152 } 153 154 if (!overflow) { 155 if ((*plow < 0) ^ (sgn_dvdnd ^ sgn_divsr)) { 156 overflow = 1; 157 } 158 } 159 160 return overflow; 161 } 162 #endif 163 164 /** 165 * urshift - 128-bit Unsigned Right Shift. 166 * @plow: in/out - lower 64-bit integer. 167 * @phigh: in/out - higher 64-bit integer. 168 * @shift: in - bytes to shift, between 0 and 127. 169 * 170 * Result is zero-extended and stored in plow/phigh, which are 171 * input/output variables. Shift values outside the range will 172 * be mod to 128. In other words, the caller is responsible to 173 * verify/assert both the shift range and plow/phigh pointers. 174 */ 175 void urshift(uint64_t *plow, uint64_t *phigh, int32_t shift) 176 { 177 shift &= 127; 178 if (shift == 0) { 179 return; 180 } 181 182 uint64_t h = *phigh >> (shift & 63); 183 if (shift >= 64) { 184 *plow = h; 185 *phigh = 0; 186 } else { 187 *plow = (*plow >> (shift & 63)) | (*phigh << (64 - (shift & 63))); 188 *phigh = h; 189 } 190 } 191 192 /** 193 * ulshift - 128-bit Unsigned Left Shift. 194 * @plow: in/out - lower 64-bit integer. 195 * @phigh: in/out - higher 64-bit integer. 196 * @shift: in - bytes to shift, between 0 and 127. 197 * @overflow: out - true if any 1-bit is shifted out. 198 * 199 * Result is zero-extended and stored in plow/phigh, which are 200 * input/output variables. Shift values outside the range will 201 * be mod to 128. In other words, the caller is responsible to 202 * verify/assert both the shift range and plow/phigh pointers. 203 */ 204 void ulshift(uint64_t *plow, uint64_t *phigh, int32_t shift, bool *overflow) 205 { 206 uint64_t low = *plow; 207 uint64_t high = *phigh; 208 209 shift &= 127; 210 if (shift == 0) { 211 return; 212 } 213 214 /* check if any bit will be shifted out */ 215 urshift(&low, &high, 128 - shift); 216 if (low | high) { 217 *overflow = true; 218 } 219 220 if (shift >= 64) { 221 *phigh = *plow << (shift & 63); 222 *plow = 0; 223 } else { 224 *phigh = (*plow >> (64 - (shift & 63))) | (*phigh << (shift & 63)); 225 *plow = *plow << shift; 226 } 227 } 228