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| 1 | +/* 64-bit multiplication and division |
| 2 | + Copyright (C) 1989, 1992-1999, 2000, 2001, 2002, 2003 |
| 3 | + Free Software Foundation, Inc. |
| 4 | + This file is part of the GNU C Library. |
| 5 | +
|
| 6 | + The GNU C Library is free software; you can redistribute it and/or |
| 7 | + modify it under the terms of the GNU Lesser General Public |
| 8 | + License as published by the Free Software Foundation; either |
| 9 | + version 2.1 of the License, or (at your option) any later version. |
| 10 | +
|
| 11 | + The GNU C Library is distributed in the hope that it will be useful, |
| 12 | + but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | + Lesser General Public License for more details. |
| 15 | +
|
| 16 | + You should have received a copy of the GNU Lesser General Public |
| 17 | + License along with the GNU C Library; if not, write to the Free |
| 18 | + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 19 | + 02111-1307 USA. */ |
| 20 | + |
| 21 | +#include "longlong.h" |
| 22 | + |
| 23 | +#define W_TYPE_SIZE (sizeof(long)) |
| 24 | + |
| 25 | +#ifdef __ARMEB__ |
| 26 | +struct DWstruct { long high, low;}; |
| 27 | +#else |
| 28 | +struct DWstruct { long low, high;}; |
| 29 | +#endif |
| 30 | + |
| 31 | +typedef union { struct DWstruct s; long long ll; } DWunion; |
| 32 | + |
| 33 | +/* Prototypes of exported functions. */ |
| 34 | +long long __divdi3 (long long u, long long v); |
| 35 | +long long __moddi3 (long long u, long long v); |
| 36 | +unsigned long long __udivdi3 (unsigned long long u, unsigned long long v); |
| 37 | +unsigned long long __umoddi3 (unsigned long long u, unsigned long long v); |
| 38 | + |
| 39 | +static unsigned long long |
| 40 | +__udivmoddi4 (unsigned long long n, unsigned long long d, unsigned long long *rp) |
| 41 | +{ |
| 42 | + DWunion ww; |
| 43 | + DWunion nn, dd; |
| 44 | + DWunion rr; |
| 45 | + unsigned long d0, d1, n0, n1, n2; |
| 46 | + unsigned long q0, q1; |
| 47 | + unsigned long b, bm; |
| 48 | + |
| 49 | + nn.ll = n; |
| 50 | + dd.ll = d; |
| 51 | + |
| 52 | + d0 = dd.s.low; |
| 53 | + d1 = dd.s.high; |
| 54 | + n0 = nn.s.low; |
| 55 | + n1 = nn.s.high; |
| 56 | + |
| 57 | +#if !UDIV_NEEDS_NORMALIZATION |
| 58 | + if (d1 == 0) |
| 59 | + { |
| 60 | + if (d0 > n1) |
| 61 | + { |
| 62 | + /* 0q = nn / 0D */ |
| 63 | + |
| 64 | + udiv_qrnnd (q0, n0, n1, n0, d0); |
| 65 | + q1 = 0; |
| 66 | + |
| 67 | + /* Remainder in n0. */ |
| 68 | + } |
| 69 | + else |
| 70 | + { |
| 71 | + /* qq = NN / 0d */ |
| 72 | + |
| 73 | + if (d0 == 0) |
| 74 | + d0 = 1 / d0; /* Divide intentionally by zero. */ |
| 75 | + |
| 76 | + udiv_qrnnd (q1, n1, 0, n1, d0); |
| 77 | + udiv_qrnnd (q0, n0, n1, n0, d0); |
| 78 | + |
| 79 | + /* Remainder in n0. */ |
| 80 | + } |
| 81 | + |
| 82 | + if (rp != 0) |
| 83 | + { |
| 84 | + rr.s.low = n0; |
| 85 | + rr.s.high = 0; |
| 86 | + *rp = rr.ll; |
| 87 | + } |
| 88 | + } |
| 89 | + |
| 90 | +#else /* UDIV_NEEDS_NORMALIZATION */ |
| 91 | + |
| 92 | + if (d1 == 0) |
| 93 | + { |
| 94 | + if (d0 > n1) |
| 95 | + { |
| 96 | + /* 0q = nn / 0D */ |
| 97 | + |
| 98 | + count_leading_zeros (bm, d0); |
| 99 | + |
| 100 | + if (bm != 0) |
| 101 | + { |
| 102 | + /* Normalize, i.e. make the most significant bit of the |
| 103 | + denominator set. */ |
| 104 | + |
| 105 | + d0 = d0 << bm; |
| 106 | + n1 = (n1 << bm) | (n0 >> (W_TYPE_SIZE - bm)); |
| 107 | + n0 = n0 << bm; |
| 108 | + } |
| 109 | + |
| 110 | + udiv_qrnnd (q0, n0, n1, n0, d0); |
| 111 | + q1 = 0; |
| 112 | + |
| 113 | + /* Remainder in n0 >> bm. */ |
| 114 | + } |
| 115 | + else |
| 116 | + { |
| 117 | + /* qq = NN / 0d */ |
| 118 | + |
| 119 | + if (d0 == 0) |
| 120 | + d0 = 1 / d0; /* Divide intentionally by zero. */ |
| 121 | + |
| 122 | + count_leading_zeros (bm, d0); |
| 123 | + |
| 124 | + if (bm == 0) |
| 125 | + { |
| 126 | + /* From (n1 >= d0) /\ (the most significant bit of d0 is set), |
| 127 | + conclude (the most significant bit of n1 is set) /\ (the |
| 128 | + leading quotient digit q1 = 1). |
| 129 | +
|
| 130 | + This special case is necessary, not an optimization. |
| 131 | + (Shifts counts of W_TYPE_SIZE are undefined.) */ |
| 132 | + |
| 133 | + n1 -= d0; |
| 134 | + q1 = 1; |
| 135 | + } |
| 136 | + else |
| 137 | + { |
| 138 | + /* Normalize. */ |
| 139 | + |
| 140 | + b = W_TYPE_SIZE - bm; |
| 141 | + |
| 142 | + d0 = d0 << bm; |
| 143 | + n2 = n1 >> b; |
| 144 | + n1 = (n1 << bm) | (n0 >> b); |
| 145 | + n0 = n0 << bm; |
| 146 | + |
| 147 | + udiv_qrnnd (q1, n1, n2, n1, d0); |
| 148 | + } |
| 149 | + |
| 150 | + /* n1 != d0... */ |
| 151 | + |
| 152 | + udiv_qrnnd (q0, n0, n1, n0, d0); |
| 153 | + |
| 154 | + /* Remainder in n0 >> bm. */ |
| 155 | + } |
| 156 | + |
| 157 | + if (rp != 0) |
| 158 | + { |
| 159 | + rr.s.low = n0 >> bm; |
| 160 | + rr.s.high = 0; |
| 161 | + *rp = rr.ll; |
| 162 | + } |
| 163 | + } |
| 164 | +#endif /* UDIV_NEEDS_NORMALIZATION */ |
| 165 | + |
| 166 | + else |
| 167 | + { |
| 168 | + if (d1 > n1) |
| 169 | + { |
| 170 | + /* 00 = nn / DD */ |
| 171 | + |
| 172 | + q0 = 0; |
| 173 | + q1 = 0; |
| 174 | + |
| 175 | + /* Remainder in n1n0. */ |
| 176 | + if (rp != 0) |
| 177 | + { |
| 178 | + rr.s.low = n0; |
| 179 | + rr.s.high = n1; |
| 180 | + *rp = rr.ll; |
| 181 | + } |
| 182 | + } |
| 183 | + else |
| 184 | + { |
| 185 | + /* 0q = NN / dd */ |
| 186 | + |
| 187 | + count_leading_zeros (bm, d1); |
| 188 | + if (bm == 0) |
| 189 | + { |
| 190 | + /* From (n1 >= d1) /\ (the most significant bit of d1 is set), |
| 191 | + conclude (the most significant bit of n1 is set) /\ (the |
| 192 | + quotient digit q0 = 0 or 1). |
| 193 | +
|
| 194 | + This special case is necessary, not an optimization. */ |
| 195 | + |
| 196 | + /* The condition on the next line takes advantage of that |
| 197 | + n1 >= d1 (true due to program flow). */ |
| 198 | + if (n1 > d1 || n0 >= d0) |
| 199 | + { |
| 200 | + q0 = 1; |
| 201 | + sub_ddmmss (n1, n0, n1, n0, d1, d0); |
| 202 | + } |
| 203 | + else |
| 204 | + q0 = 0; |
| 205 | + |
| 206 | + q1 = 0; |
| 207 | + |
| 208 | + if (rp != 0) |
| 209 | + { |
| 210 | + rr.s.low = n0; |
| 211 | + rr.s.high = n1; |
| 212 | + *rp = rr.ll; |
| 213 | + } |
| 214 | + } |
| 215 | + else |
| 216 | + { |
| 217 | + unsigned long m1, m0; |
| 218 | + /* Normalize. */ |
| 219 | + |
| 220 | + b = W_TYPE_SIZE - bm; |
| 221 | + |
| 222 | + d1 = (d1 << bm) | (d0 >> b); |
| 223 | + d0 = d0 << bm; |
| 224 | + n2 = n1 >> b; |
| 225 | + n1 = (n1 << bm) | (n0 >> b); |
| 226 | + n0 = n0 << bm; |
| 227 | + |
| 228 | + udiv_qrnnd (q0, n1, n2, n1, d1); |
| 229 | + umul_ppmm (m1, m0, q0, d0); |
| 230 | + |
| 231 | + if (m1 > n1 || (m1 == n1 && m0 > n0)) |
| 232 | + { |
| 233 | + q0--; |
| 234 | + sub_ddmmss (m1, m0, m1, m0, d1, d0); |
| 235 | + } |
| 236 | + |
| 237 | + q1 = 0; |
| 238 | + |
| 239 | + /* Remainder in (n1n0 - m1m0) >> bm. */ |
| 240 | + if (rp != 0) |
| 241 | + { |
| 242 | + sub_ddmmss (n1, n0, n1, n0, m1, m0); |
| 243 | + rr.s.low = (n1 << b) | (n0 >> bm); |
| 244 | + rr.s.high = n1 >> bm; |
| 245 | + *rp = rr.ll; |
| 246 | + } |
| 247 | + } |
| 248 | + } |
| 249 | + } |
| 250 | + |
| 251 | + ww.s.low = q0; |
| 252 | + ww.s.high = q1; |
| 253 | + return ww.ll; |
| 254 | +} |
| 255 | + |
| 256 | +long long |
| 257 | +__divdi3 (long long u, long long v) |
| 258 | +{ |
| 259 | + long c = 0; |
| 260 | + long long w; |
| 261 | + |
| 262 | + if (u < 0) |
| 263 | + { |
| 264 | + c = ~c; |
| 265 | + u = -u; |
| 266 | + } |
| 267 | + if (v < 0) |
| 268 | + { |
| 269 | + c = ~c; |
| 270 | + v = -v; |
| 271 | + } |
| 272 | + w = __udivmoddi4 (u, v, 0); |
| 273 | + if (c) |
| 274 | + w = -w; |
| 275 | + return w; |
| 276 | +} |
| 277 | + |
| 278 | +long long |
| 279 | +__moddi3 (long long u, long long v) |
| 280 | +{ |
| 281 | + long c = 0; |
| 282 | + long long w; |
| 283 | + |
| 284 | + if (u < 0) |
| 285 | + { |
| 286 | + c = ~c; |
| 287 | + u = -u; |
| 288 | + } |
| 289 | + if (v < 0) |
| 290 | + v = -v; |
| 291 | + __udivmoddi4 (u, v, &w); |
| 292 | + if (c) |
| 293 | + w = -w; |
| 294 | + return w; |
| 295 | +} |
| 296 | + |
| 297 | +unsigned long long |
| 298 | +__udivdi3 (unsigned long long u, unsigned long long v) |
| 299 | +{ |
| 300 | + return __udivmoddi4 (u, v, 0); |
| 301 | +} |
| 302 | + |
| 303 | +unsigned long long |
| 304 | +__umoddi3 (unsigned long long u, unsigned long long v) |
| 305 | +{ |
| 306 | + unsigned long long w; |
| 307 | + |
| 308 | + __udivmoddi4 (u, v, &w); |
| 309 | + return w; |
| 310 | +} |
| 311 | + |
| 312 | +long long |
| 313 | +__gnu_ldivmod_helper (long long a, |
| 314 | + |
| 315 | + long long b, |
| 316 | + long long *remainder) |
| 317 | +{ |
| 318 | + long long quotient; |
| 319 | + |
| 320 | + quotient = __divdi3 (a, b); |
| 321 | + *remainder = a - b * quotient; |
| 322 | + |
| 323 | + return quotient; |
| 324 | +} |
| 325 | + |
| 326 | +unsigned long long |
| 327 | + |
| 328 | +__gnu_uldivmod_helper (unsigned long long a, |
| 329 | + |
| 330 | + unsigned long long b, |
| 331 | + unsigned long long *remainder) |
| 332 | +{ |
| 333 | + unsigned long long quotient; |
| 334 | + |
| 335 | + quotient = __udivdi3 (a, b); |
| 336 | + *remainder = a - b * quotient; |
| 337 | + return quotient; |
| 338 | +} |
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