1 /** @file 2 Compiler intrinsic for 64-bit compare, ported from LLVM code. 3 4 Copyright (c) 2008-2009, Apple Inc. All rights reserved.<BR> 5 6 This program and the accompanying materials 7 are licensed and made available under the terms and conditions of the BSD License 8 which accompanies this distribution. The full text of the license may be found at 9 http://opensource.org/licenses/bsd-license.php 10 11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 13 14 **/ 15 /** 16 University of Illinois/NCSA 17 Open Source License 18 19 Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign. 20 All rights reserved. 21 22 Developed by: 23 24 LLVM Team 25 26 University of Illinois at Urbana-Champaign 27 28 http://llvm.org 29 30 Permission is hereby granted, free of charge, to any person obtaining a copy of 31 this software and associated documentation files (the "Software"), to deal with 32 the Software without restriction, including without limitation the rights to 33 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 34 of the Software, and to permit persons to whom the Software is furnished to do 35 so, subject to the following conditions: 36 37 * Redistributions of source code must retain the above copyright notice, 38 this list of conditions and the following disclaimers. 39 40 * Redistributions in binary form must reproduce the above copyright notice, 41 this list of conditions and the following disclaimers in the 42 documentation and/or other materials provided with the distribution. 43 44 * Neither the names of the LLVM Team, University of Illinois at 45 Urbana-Champaign, nor the names of its contributors may be used to 46 endorse or promote products derived from this Software without specific 47 prior written permission. 48 49 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 50 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 51 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 52 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 53 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 54 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE 55 SOFTWARE. 56 **/ 57 58 59 #include "Llvm_int_lib.h" 60 61 // Effects: if rem != 0, *rem = a % b 62 // Returns: a / b 63 64 // Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide 65 66 UINT64 67 __udivmoddi4 (UINT64 a, UINT64 b, UINT64* rem) 68 { 69 const unsigned n_uword_bits = sizeof(UINT32) * CHAR_BIT; 70 const unsigned n_udword_bits = sizeof(UINT64) * CHAR_BIT; 71 udwords n; 72 n.all = a; 73 udwords d; 74 d.all = b; 75 udwords q; 76 udwords r; 77 unsigned sr; 78 79 if (b == 0) { 80 // ASSERT (FALSE); 81 return 0; 82 } 83 84 // special cases, X is unknown, K != 0 85 if (n.high == 0) 86 { 87 if (d.high == 0) 88 { 89 // 0 X 90 // --- 91 // 0 X 92 if (rem) 93 *rem = n.low % d.low; 94 return n.low / d.low; 95 } 96 // 0 X 97 // --- 98 // K X 99 if (rem) 100 *rem = n.low; 101 return 0; 102 } 103 // n.high != 0 104 if (d.low == 0) 105 { 106 if (d.high == 0) 107 { 108 // K X 109 // --- 110 // 0 0 111 if (rem) 112 *rem = n.high % d.low; 113 return n.high / d.low; 114 } 115 // d.high != 0 116 if (n.low == 0) 117 { 118 // K 0 119 // --- 120 // K 0 121 if (rem) 122 { 123 r.high = n.high % d.high; 124 r.low = 0; 125 *rem = r.all; 126 } 127 return n.high / d.high; 128 } 129 // K K 130 // --- 131 // K 0 132 if ((d.high & (d.high - 1)) == 0) // if d is a power of 2 133 { 134 if (rem) 135 { 136 r.low = n.low; 137 r.high = n.high & (d.high - 1); 138 *rem = r.all; 139 } 140 return n.high >> COUNT_TRAILING_ZEROS(d.high); 141 } 142 // K K 143 // --- 144 // K 0 145 sr = COUNT_LEADING_ZEROS(d.high) - COUNT_LEADING_ZEROS(n.high); 146 // 0 <= sr <= n_uword_bits - 2 or sr large 147 if (sr > n_uword_bits - 2) 148 { 149 if (rem) 150 *rem = n.all; 151 return 0; 152 } 153 ++sr; 154 // 1 <= sr <= n_uword_bits - 1 155 // q.all = n.all << (n_udword_bits - sr); 156 q.low = 0; 157 q.high = n.low << (n_uword_bits - sr); 158 // r.all = n.all >> sr; 159 r.high = n.high >> sr; 160 r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); 161 } 162 else // d.low != 0 163 { 164 if (d.high == 0) 165 { 166 // K X 167 // --- 168 // 0 K 169 if ((d.low & (d.low - 1)) == 0) // if d is a power of 2 170 { 171 if (rem) 172 *rem = n.low & (d.low - 1); 173 if (d.low == 1) 174 return n.all; 175 unsigned sr = COUNT_TRAILING_ZEROS(d.low); 176 q.high = n.high >> sr; 177 q.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); 178 return q.all; 179 } 180 // K X 181 // --- 182 // 0 K 183 sr = 1 + n_uword_bits + COUNT_LEADING_ZEROS(d.low) - COUNT_LEADING_ZEROS(n.high); 184 // 2 <= sr <= n_udword_bits - 1 185 // q.all = n.all << (n_udword_bits - sr); 186 // r.all = n.all >> sr; 187 // if (sr == n_uword_bits) 188 // { 189 // q.low = 0; 190 // q.high = n.low; 191 // r.high = 0; 192 // r.low = n.high; 193 // } 194 // else if (sr < n_uword_bits) // 2 <= sr <= n_uword_bits - 1 195 // { 196 // q.low = 0; 197 // q.high = n.low << (n_uword_bits - sr); 198 // r.high = n.high >> sr; 199 // r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); 200 // } 201 // else // n_uword_bits + 1 <= sr <= n_udword_bits - 1 202 // { 203 // q.low = n.low << (n_udword_bits - sr); 204 // q.high = (n.high << (n_udword_bits - sr)) | 205 // (n.low >> (sr - n_uword_bits)); 206 // r.high = 0; 207 // r.low = n.high >> (sr - n_uword_bits); 208 // } 209 q.low = (n.low << (n_udword_bits - sr)) & 210 ((INT32)(n_uword_bits - sr) >> (n_uword_bits-1)); 211 q.high = ((n.low << ( n_uword_bits - sr)) & 212 ((INT32)(sr - n_uword_bits - 1) >> (n_uword_bits-1))) | 213 (((n.high << (n_udword_bits - sr)) | 214 (n.low >> (sr - n_uword_bits))) & 215 ((INT32)(n_uword_bits - sr) >> (n_uword_bits-1))); 216 r.high = (n.high >> sr) & 217 ((INT32)(sr - n_uword_bits) >> (n_uword_bits-1)); 218 r.low = ((n.high >> (sr - n_uword_bits)) & 219 ((INT32)(n_uword_bits - sr - 1) >> (n_uword_bits-1))) | 220 (((n.high << (n_uword_bits - sr)) | 221 (n.low >> sr)) & 222 ((INT32)(sr - n_uword_bits) >> (n_uword_bits-1))); 223 } 224 else 225 { 226 // K X 227 // --- 228 // K K 229 sr = COUNT_LEADING_ZEROS(d.high) - COUNT_LEADING_ZEROS(n.high); 230 // 0 <= sr <= n_uword_bits - 1 or sr large 231 if (sr > n_uword_bits - 1) 232 { 233 if (rem) 234 *rem = n.all; 235 return 0; 236 } 237 ++sr; 238 // 1 <= sr <= n_uword_bits 239 // q.all = n.all << (n_udword_bits - sr); 240 q.low = 0; 241 q.high = n.low << (n_uword_bits - sr); 242 // r.all = n.all >> sr; 243 // if (sr < n_uword_bits) 244 // { 245 // r.high = n.high >> sr; 246 // r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); 247 // } 248 // else 249 // { 250 // r.high = 0; 251 // r.low = n.high; 252 // } 253 r.high = (n.high >> sr) & 254 ((INT32)(sr - n_uword_bits) >> (n_uword_bits-1)); 255 r.low = (n.high << (n_uword_bits - sr)) | 256 ((n.low >> sr) & 257 ((INT32)(sr - n_uword_bits) >> (n_uword_bits-1))); 258 } 259 } 260 // Not a special case 261 // q and r are initialized with: 262 // q.all = n.all << (n_udword_bits - sr); 263 // r.all = n.all >> sr; 264 // 1 <= sr <= n_udword_bits - 1 265 UINT32 carry = 0; 266 for (; sr > 0; --sr) 267 { 268 // r:q = ((r:q) << 1) | carry 269 r.high = (r.high << 1) | (r.low >> (n_uword_bits - 1)); 270 r.low = (r.low << 1) | (q.high >> (n_uword_bits - 1)); 271 q.high = (q.high << 1) | (q.low >> (n_uword_bits - 1)); 272 q.low = (q.low << 1) | carry; 273 // carry = 0; 274 // if (r.all >= d.all) 275 // { 276 // r.all -= d.all; 277 // carry = 1; 278 // } 279 const INT64 s = (INT64)(d.all - r.all - 1) >> (n_udword_bits - 1); 280 carry = s & 1; 281 r.all -= d.all & s; 282 } 283 q.all = (q.all << 1) | carry; 284 if (rem) 285 *rem = r.all; 286 return q.all; 287 } 288
