epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 8 | #include "Sk64.h" |
reed@google.com | 4b163ed | 2012-08-07 21:35:13 +0000 | [diff] [blame] | 9 | #include "SkMathPriv.h" |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 10 | |
| 11 | #define shift_left(hi, lo) \ |
| 12 | hi = (hi << 1) | (lo >> 31); \ |
| 13 | lo <<= 1 |
| 14 | |
| 15 | #define shift_left_bits(hi, lo, bits) \ |
| 16 | SkASSERT((unsigned)(bits) < 31); \ |
| 17 | hi = (hi << (bits)) | (lo >> (32 - (bits))); \ |
| 18 | lo <<= (bits) |
| 19 | |
| 20 | ////////////////////////////////////////////////////////////////////// |
| 21 | |
| 22 | int Sk64::getClzAbs() const |
| 23 | { |
| 24 | int32_t hi = fHi; |
| 25 | uint32_t lo = fLo; |
| 26 | |
| 27 | // get abs |
| 28 | if (hi < 0) |
| 29 | { |
| 30 | hi = -hi - Sk32ToBool(lo); |
| 31 | lo = 0 - lo; |
| 32 | } |
| 33 | return hi ? SkCLZ(hi) : SkCLZ(lo) + 32; |
| 34 | } |
| 35 | |
| 36 | void Sk64::shiftLeft(unsigned bits) |
| 37 | { |
| 38 | SkASSERT(bits <= 63); |
| 39 | if (bits == 0) |
| 40 | return; |
| 41 | |
| 42 | if (bits >= 32) |
| 43 | { |
| 44 | fHi = fLo << (bits - 32); |
| 45 | fLo = 0; |
| 46 | } |
| 47 | else |
| 48 | { |
| 49 | fHi = (fHi << bits) | (fLo >> (32 - bits)); |
| 50 | fLo <<= bits; |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | int32_t Sk64::getShiftRight(unsigned bits) const |
| 55 | { |
| 56 | SkASSERT(bits <= 63); |
| 57 | |
| 58 | if (bits == 0) |
| 59 | return fLo; |
| 60 | |
| 61 | if (bits >= 32) |
| 62 | return fHi >> (bits - 32); |
| 63 | else |
| 64 | { |
| 65 | #ifdef SK_DEBUG |
| 66 | int32_t tmp = fHi >> bits; |
| 67 | SkASSERT(tmp == 0 || tmp == -1); |
| 68 | #endif |
| 69 | return (fHi << (32 - bits)) | (fLo >> bits); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | void Sk64::shiftRight(unsigned bits) |
| 74 | { |
| 75 | SkASSERT(bits <= 63); |
| 76 | if (bits == 0) |
| 77 | return; |
| 78 | |
| 79 | if (bits >= 32) |
| 80 | { |
| 81 | fLo = fHi >> (bits - 32); |
| 82 | fHi >>= 31; |
| 83 | } |
| 84 | else |
| 85 | { |
| 86 | fLo = (fHi << (32 - bits)) | (fLo >> bits); |
| 87 | fHi >>= bits; |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | void Sk64::roundRight(unsigned bits) |
| 92 | { |
| 93 | SkASSERT(bits <= 63); |
| 94 | if (bits) |
| 95 | { |
| 96 | Sk64 one; |
| 97 | one.set(1); |
| 98 | one.shiftLeft(bits - 1); |
| 99 | this->add(one); |
| 100 | this->shiftRight(bits); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | int Sk64::shiftToMake32() const |
| 105 | { |
| 106 | int32_t hi = fHi; |
| 107 | uint32_t lo = fLo; |
| 108 | |
| 109 | if (hi < 0) // make it positive |
| 110 | { |
| 111 | hi = -hi - Sk32ToBool(lo); |
| 112 | lo = 0 - lo; |
| 113 | } |
| 114 | |
| 115 | if (hi == 0) |
| 116 | return lo >> 31; |
| 117 | else |
| 118 | return 33 - SkCLZ(hi); |
| 119 | } |
| 120 | |
| 121 | void Sk64::negate() |
| 122 | { |
| 123 | fHi = -fHi - Sk32ToBool(fLo); |
| 124 | fLo = 0 - fLo; |
| 125 | } |
| 126 | |
| 127 | void Sk64::abs() |
| 128 | { |
| 129 | if (fHi < 0) |
| 130 | { |
| 131 | fHi = -fHi - Sk32ToBool(fLo); |
| 132 | fLo = 0 - fLo; |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | //////////////////////////////////////////////////////////////// |
| 137 | |
| 138 | static inline int32_t round_right_16(int32_t hi, uint32_t lo) |
| 139 | { |
| 140 | uint32_t sum = lo + (1 << 15); |
| 141 | hi += (sum < lo); |
| 142 | return (hi << 16) | (sum >> 16); |
| 143 | } |
| 144 | |
| 145 | SkBool Sk64::isFixed() const |
| 146 | { |
| 147 | Sk64 tmp = *this; |
| 148 | tmp.roundRight(16); |
| 149 | return tmp.is32(); |
| 150 | } |
| 151 | |
| 152 | SkFract Sk64::getFract() const |
| 153 | { |
| 154 | Sk64 tmp = *this; |
| 155 | tmp.roundRight(30); |
| 156 | return tmp.get32(); |
| 157 | } |
| 158 | |
| 159 | void Sk64::sub(const Sk64& a) |
| 160 | { |
| 161 | fHi = fHi - a.fHi - (fLo < a.fLo); |
| 162 | fLo = fLo - a.fLo; |
| 163 | } |
| 164 | |
| 165 | void Sk64::rsub(const Sk64& a) |
| 166 | { |
| 167 | fHi = a.fHi - fHi - (a.fLo < fLo); |
| 168 | fLo = a.fLo - fLo; |
| 169 | } |
| 170 | |
| 171 | void Sk64::setMul(int32_t a, int32_t b) |
| 172 | { |
| 173 | int sa = a >> 31; |
| 174 | int sb = b >> 31; |
| 175 | // now make them positive |
| 176 | a = (a ^ sa) - sa; |
| 177 | b = (b ^ sb) - sb; |
| 178 | |
| 179 | uint32_t ah = a >> 16; |
| 180 | uint32_t al = a & 0xFFFF; |
| 181 | uint32_t bh = b >> 16; |
| 182 | uint32_t bl = b & 0xFFFF; |
| 183 | |
| 184 | uint32_t A = ah * bh; |
| 185 | uint32_t B = ah * bl + al * bh; |
| 186 | uint32_t C = al * bl; |
| 187 | |
| 188 | /* [ A ] |
| 189 | [ B ] |
| 190 | [ C ] |
| 191 | */ |
| 192 | fLo = C + (B << 16); |
| 193 | fHi = A + (B >>16) + (fLo < C); |
| 194 | |
| 195 | if (sa != sb) |
| 196 | this->negate(); |
| 197 | } |
| 198 | |
| 199 | void Sk64::div(int32_t denom, DivOptions option) |
| 200 | { |
| 201 | SkASSERT(denom); |
| 202 | |
| 203 | int32_t hi = fHi; |
| 204 | uint32_t lo = fLo; |
| 205 | int sign = denom ^ hi; |
| 206 | |
| 207 | denom = SkAbs32(denom); |
| 208 | if (hi < 0) |
| 209 | { |
| 210 | hi = -hi - Sk32ToBool(lo); |
| 211 | lo = 0 - lo; |
| 212 | } |
| 213 | |
| 214 | if (option == kRound_DivOption) // add denom/2 |
| 215 | { |
| 216 | uint32_t newLo = lo + (denom >> 1); |
| 217 | hi += (newLo < lo); |
| 218 | lo = newLo; |
| 219 | } |
| 220 | |
| 221 | if (hi == 0) // fast-case |
| 222 | { |
| 223 | if (lo < (uint32_t)denom) |
| 224 | this->set(0, 0); |
| 225 | else |
| 226 | { |
| 227 | this->set(0, lo / denom); |
| 228 | if (sign < 0) |
| 229 | this->negate(); |
| 230 | } |
| 231 | return; |
| 232 | } |
| 233 | |
| 234 | int bits; |
| 235 | |
| 236 | { |
| 237 | int dbits = SkCLZ(denom); |
| 238 | int nbits = SkCLZ(hi); |
| 239 | |
| 240 | bits = 32 + dbits - nbits; |
| 241 | SkASSERT(bits <= 63); |
| 242 | if (bits <= 0) |
| 243 | { |
| 244 | this->set(0, 0); |
| 245 | return; |
| 246 | } |
| 247 | denom <<= (dbits - 1); |
| 248 | shift_left_bits(hi, lo, nbits - 1); |
| 249 | } |
| 250 | |
| 251 | int32_t rhi = 0; |
| 252 | uint32_t rlo = 0; |
| 253 | |
| 254 | do { |
| 255 | shift_left(rhi, rlo); |
| 256 | #ifdef SK_CPU_HAS_CONDITIONAL_INSTR |
| 257 | if ((uint32_t)denom <= (uint32_t)hi) |
| 258 | { |
| 259 | hi -= denom; |
| 260 | rlo |= 1; |
| 261 | } |
| 262 | #else |
| 263 | int32_t diff = (denom - hi - 1) >> 31; |
| 264 | hi -= denom & diff; |
| 265 | rlo -= diff; |
| 266 | #endif |
| 267 | shift_left(hi, lo); |
| 268 | } while (--bits >= 0); |
| 269 | SkASSERT(rhi >= 0); |
| 270 | |
| 271 | fHi = rhi; |
| 272 | fLo = rlo; |
| 273 | if (sign < 0) |
| 274 | this->negate(); |
| 275 | } |
| 276 | |
| 277 | #define shift_left_2(a, b, c) \ |
| 278 | a = (a << 2) | (b >> 30); \ |
| 279 | b = (b << 2) | (c >> 30); \ |
| 280 | c <<= 2 |
| 281 | |
| 282 | int32_t Sk64::getSqrt() const |
| 283 | { |
| 284 | SkASSERT(!this->isNeg()); |
| 285 | |
| 286 | uint32_t hi = fHi; |
| 287 | uint32_t lo = fLo; |
| 288 | uint32_t sqr = 0; |
| 289 | uint32_t root = 0; |
| 290 | int count = 31; |
| 291 | |
| 292 | do { |
| 293 | root <<= 1; |
| 294 | shift_left_2(sqr, hi, lo); |
| 295 | |
| 296 | uint32_t testDiv = (root << 1) + 1; |
| 297 | if (sqr >= testDiv) |
| 298 | { |
| 299 | sqr -= testDiv; |
| 300 | root++; |
| 301 | } |
| 302 | } while (--count >= 0); |
| 303 | SkASSERT((int32_t)root >= 0); |
| 304 | |
| 305 | return root; |
| 306 | } |
| 307 | |
| 308 | #ifdef SkLONGLONG |
| 309 | SkLONGLONG Sk64::getLongLong() const |
| 310 | { |
| 311 | SkLONGLONG value = fHi; |
| 312 | value <<= 32; |
| 313 | return value | fLo; |
| 314 | } |
| 315 | #endif |
| 316 | |
| 317 | SkFixed Sk64::getFixedDiv(const Sk64& denom) const |
| 318 | { |
| 319 | Sk64 N = *this; |
| 320 | Sk64 D = denom; |
| 321 | int32_t sign = SkExtractSign(N.fHi ^ D.fHi); |
| 322 | SkFixed result; |
| 323 | |
| 324 | N.abs(); |
| 325 | D.abs(); |
| 326 | |
| 327 | // need to knock D down to just 31 bits |
| 328 | // either by rounding it to the right, or shifting N to the left |
| 329 | // then we can just call 64/32 div |
| 330 | |
| 331 | int nclz = N.fHi ? SkCLZ(N.fHi) : 32; |
| 332 | int dclz = D.fHi ? SkCLZ(D.fHi) : (33 - (D.fLo >> 31)); |
| 333 | |
| 334 | int shiftN = nclz - 1; |
| 335 | SkASSERT(shiftN >= 0); |
| 336 | int shiftD = 33 - dclz; |
| 337 | SkASSERT(shiftD >= 0); |
| 338 | |
| 339 | if (shiftD + shiftN < 16) |
| 340 | shiftD = 16 - shiftN; |
| 341 | else |
| 342 | shiftN = 16 - shiftD; |
| 343 | |
| 344 | D.roundRight(shiftD); |
| 345 | if (D.isZero()) |
| 346 | result = SK_MaxS32; |
| 347 | else |
| 348 | { |
| 349 | if (shiftN >= 0) |
| 350 | N.shiftLeft(shiftN); |
| 351 | else |
| 352 | N.roundRight(-shiftN); |
| 353 | N.div(D.get32(), Sk64::kTrunc_DivOption); |
| 354 | if (N.is32()) |
| 355 | result = N.get32(); |
| 356 | else |
| 357 | result = SK_MaxS32; |
| 358 | } |
| 359 | return SkApplySign(result, sign); |
| 360 | } |