Changes in uspace/lib/softfloat/generic/sub.c [c67aff2:750636a] in mainline
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uspace/lib/softfloat/generic/sub.c (modified) (13 diffs)
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uspace/lib/softfloat/generic/sub.c
rc67aff2 r750636a 1 1 /* 2 2 * Copyright (c) 2005 Josef Cejka 3 * Copyright (c) 2011 Petr Koupy4 3 * All rights reserved. 5 4 * … … 31 30 * @{ 32 31 */ 33 /** @file Substraction functions.32 /** @file 34 33 */ 35 34 … … 37 36 #include <sub.h> 38 37 #include <comparison.h> 39 #include <common.h> 40 41 /** 42 * Subtract two single-precision floats with the same signs. 43 * 44 * @param a First input operand. 45 * @param b Second input operand. 46 * @return Result of substraction. 38 39 /** Subtract two float32 numbers with same signs 47 40 */ 48 41 float32 subFloat32(float32 a, float32 b) … … 59 52 /* TODO: fix SigNaN */ 60 53 if (isFloat32SigNaN(b)) { 61 } 62 return b; 63 } 54 }; 55 return b; 56 }; 64 57 65 58 if (b.parts.exp == FLOAT32_MAX_EXPONENT) { … … 79 72 /* TODO: fix SigNaN */ 80 73 if (isFloat32SigNaN(a) || isFloat32SigNaN(b)) { 81 } 82 return a; 83 } 74 }; 75 return a; 76 }; 84 77 85 78 if (a.parts.exp == FLOAT32_MAX_EXPONENT) { … … 89 82 result.binary = FLOAT32_NAN; 90 83 return result; 91 } 84 }; 92 85 return a; 93 86 } … … 99 92 frac2 = b.parts.fraction; 100 93 exp2 = b.parts.exp; 101 } 94 }; 95 96 if (exp1 == 0) { 97 /* both are denormalized */ 98 result.parts.fraction = frac1-frac2; 99 if (result.parts.fraction > frac1) { 100 /* TODO: underflow exception */ 101 return result; 102 }; 103 result.parts.exp = 0; 104 return result; 105 }; 106 107 /* add hidden bit */ 108 frac1 |= FLOAT32_HIDDEN_BIT_MASK; 109 110 if (exp2 == 0) { 111 /* denormalized */ 112 --expdiff; 113 } else { 114 /* normalized */ 115 frac2 |= FLOAT32_HIDDEN_BIT_MASK; 116 }; 117 118 /* create some space for rounding */ 119 frac1 <<= 6; 120 frac2 <<= 6; 121 122 if (expdiff > FLOAT32_FRACTION_SIZE + 1) { 123 goto done; 124 }; 125 126 frac1 = frac1 - (frac2 >> expdiff); 127 done: 128 /* TODO: find first nonzero digit and shift result and detect possibly underflow */ 129 while ((exp1 > 0) && (!(frac1 & (FLOAT32_HIDDEN_BIT_MASK << 6 )))) { 130 --exp1; 131 frac1 <<= 1; 132 /* TODO: fix underflow - frac1 == 0 does not necessary means underflow... */ 133 }; 134 135 /* rounding - if first bit after fraction is set then round up */ 136 frac1 += 0x20; 137 138 if (frac1 & (FLOAT32_HIDDEN_BIT_MASK << 7)) { 139 ++exp1; 140 frac1 >>= 1; 141 }; 142 143 /*Clear hidden bit and shift */ 144 result.parts.fraction = ((frac1 >> 6) & (~FLOAT32_HIDDEN_BIT_MASK)); 145 result.parts.exp = exp1; 146 147 return result; 148 } 149 150 /** Subtract two float64 numbers with same signs 151 */ 152 float64 subFloat64(float64 a, float64 b) 153 { 154 int expdiff; 155 uint32_t exp1, exp2; 156 uint64_t frac1, frac2; 157 float64 result; 158 159 result.d = 0; 160 161 expdiff = a.parts.exp - b.parts.exp; 162 if ((expdiff < 0 ) || ((expdiff == 0) && (a.parts.fraction < b.parts.fraction))) { 163 if (isFloat64NaN(b)) { 164 /* TODO: fix SigNaN */ 165 if (isFloat64SigNaN(b)) { 166 }; 167 return b; 168 }; 169 170 if (b.parts.exp == FLOAT64_MAX_EXPONENT) { 171 b.parts.sign = !b.parts.sign; /* num -(+-inf) = -+inf */ 172 return b; 173 } 174 175 result.parts.sign = !a.parts.sign; 176 177 frac1 = b.parts.fraction; 178 exp1 = b.parts.exp; 179 frac2 = a.parts.fraction; 180 exp2 = a.parts.exp; 181 expdiff *= -1; 182 } else { 183 if (isFloat64NaN(a)) { 184 /* TODO: fix SigNaN */ 185 if (isFloat64SigNaN(a) || isFloat64SigNaN(b)) { 186 }; 187 return a; 188 }; 189 190 if (a.parts.exp == FLOAT64_MAX_EXPONENT) { 191 if (b.parts.exp == FLOAT64_MAX_EXPONENT) { 192 /* inf - inf => nan */ 193 /* TODO: fix exception */ 194 result.binary = FLOAT64_NAN; 195 return result; 196 }; 197 return a; 198 } 199 200 result.parts.sign = a.parts.sign; 201 202 frac1 = a.parts.fraction; 203 exp1 = a.parts.exp; 204 frac2 = b.parts.fraction; 205 exp2 = b.parts.exp; 206 }; 102 207 103 208 if (exp1 == 0) { … … 107 212 /* TODO: underflow exception */ 108 213 return result; 109 } 214 }; 110 215 result.parts.exp = 0; 111 216 return result; 112 } 217 }; 113 218 114 219 /* add hidden bit */ 115 frac1 |= FLOAT 32_HIDDEN_BIT_MASK;220 frac1 |= FLOAT64_HIDDEN_BIT_MASK; 116 221 117 222 if (exp2 == 0) { … … 120 225 } else { 121 226 /* normalized */ 122 frac2 |= FLOAT 32_HIDDEN_BIT_MASK;123 } 227 frac2 |= FLOAT64_HIDDEN_BIT_MASK; 228 }; 124 229 125 230 /* create some space for rounding */ … … 127 232 frac2 <<= 6; 128 233 129 if (expdiff > FLOAT 32_FRACTION_SIZE + 1) {130 goto done;131 }234 if (expdiff > FLOAT64_FRACTION_SIZE + 1) { 235 goto done; 236 }; 132 237 133 238 frac1 = frac1 - (frac2 >> expdiff); 134 135 done:136 /* TODO: find first nonzero digit and shift result and detect possibly underflow */137 while ((exp1 > 0) && (!(frac1 & (FLOAT32_HIDDEN_BIT_MASK << 6 )))) {138 --exp1;139 frac1 <<= 1;140 /* TODO: fix underflow - frac1 == 0 does not necessary means underflow... */141 }142 143 /* rounding - if first bit after fraction is set then round up */144 frac1 += 0x20;145 146 if (frac1 & (FLOAT32_HIDDEN_BIT_MASK << 7)) {147 ++exp1;148 frac1 >>= 1;149 }150 151 /* Clear hidden bit and shift */152 result.parts.fraction = ((frac1 >> 6) & (~FLOAT32_HIDDEN_BIT_MASK));153 result.parts.exp = exp1;154 155 return result;156 }157 158 /**159 * Subtract two double-precision floats with the same signs.160 *161 * @param a First input operand.162 * @param b Second input operand.163 * @return Result of substraction.164 */165 float64 subFloat64(float64 a, float64 b)166 {167 int expdiff;168 uint32_t exp1, exp2;169 uint64_t frac1, frac2;170 float64 result;171 172 result.d = 0;173 174 expdiff = a.parts.exp - b.parts.exp;175 if ((expdiff < 0 ) || ((expdiff == 0) && (a.parts.fraction < b.parts.fraction))) {176 if (isFloat64NaN(b)) {177 /* TODO: fix SigNaN */178 if (isFloat64SigNaN(b)) {179 }180 return b;181 }182 183 if (b.parts.exp == FLOAT64_MAX_EXPONENT) {184 b.parts.sign = !b.parts.sign; /* num -(+-inf) = -+inf */185 return b;186 }187 188 result.parts.sign = !a.parts.sign;189 190 frac1 = b.parts.fraction;191 exp1 = b.parts.exp;192 frac2 = a.parts.fraction;193 exp2 = a.parts.exp;194 expdiff *= -1;195 } else {196 if (isFloat64NaN(a)) {197 /* TODO: fix SigNaN */198 if (isFloat64SigNaN(a) || isFloat64SigNaN(b)) {199 }200 return a;201 }202 203 if (a.parts.exp == FLOAT64_MAX_EXPONENT) {204 if (b.parts.exp == FLOAT64_MAX_EXPONENT) {205 /* inf - inf => nan */206 /* TODO: fix exception */207 result.binary = FLOAT64_NAN;208 return result;209 }210 return a;211 }212 213 result.parts.sign = a.parts.sign;214 215 frac1 = a.parts.fraction;216 exp1 = a.parts.exp;217 frac2 = b.parts.fraction;218 exp2 = b.parts.exp;219 }220 221 if (exp1 == 0) {222 /* both are denormalized */223 result.parts.fraction = frac1 - frac2;224 if (result.parts.fraction > frac1) {225 /* TODO: underflow exception */226 return result;227 }228 result.parts.exp = 0;229 return result;230 }231 232 /* add hidden bit */233 frac1 |= FLOAT64_HIDDEN_BIT_MASK;234 235 if (exp2 == 0) {236 /* denormalized */237 --expdiff;238 } else {239 /* normalized */240 frac2 |= FLOAT64_HIDDEN_BIT_MASK;241 }242 243 /* create some space for rounding */244 frac1 <<= 6;245 frac2 <<= 6;246 247 if (expdiff > FLOAT64_FRACTION_SIZE + 1) {248 goto done;249 }250 251 frac1 = frac1 - (frac2 >> expdiff);252 253 239 done: 254 240 /* TODO: find first nonzero digit and shift result and detect possibly underflow */ … … 256 242 --exp1; 257 243 frac1 <<= 1; 258 /* TODO: fix underflow - frac1 == 0 does not necessary means underflow... */259 } 244 /* TODO: fix underflow - frac1 == 0 does not necessary means underflow... */ 245 }; 260 246 261 247 /* rounding - if first bit after fraction is set then round up */ … … 265 251 ++exp1; 266 252 frac1 >>= 1; 267 } 268 269 /* 253 }; 254 255 /*Clear hidden bit and shift */ 270 256 result.parts.fraction = ((frac1 >> 6) & (~FLOAT64_HIDDEN_BIT_MASK)); 271 257 result.parts.exp = exp1; … … 274 260 } 275 261 276 /**277 * Subtract two quadruple-precision floats with the same signs.278 *279 * @param a First input operand.280 * @param b Second input operand.281 * @return Result of substraction.282 */283 float128 subFloat128(float128 a, float128 b)284 {285 int expdiff;286 uint32_t exp1, exp2;287 uint64_t frac1_hi, frac1_lo, frac2_hi, frac2_lo, tmp_hi, tmp_lo;288 float128 result;289 290 result.binary.hi = 0;291 result.binary.lo = 0;292 293 expdiff = a.parts.exp - b.parts.exp;294 if ((expdiff < 0 ) || ((expdiff == 0) &&295 lt128(a.parts.frac_hi, a.parts.frac_lo, b.parts.frac_hi, b.parts.frac_lo))) {296 if (isFloat128NaN(b)) {297 /* TODO: fix SigNaN */298 if (isFloat128SigNaN(b)) {299 }300 return b;301 }302 303 if (b.parts.exp == FLOAT128_MAX_EXPONENT) {304 b.parts.sign = !b.parts.sign; /* num -(+-inf) = -+inf */305 return b;306 }307 308 result.parts.sign = !a.parts.sign;309 310 frac1_hi = b.parts.frac_hi;311 frac1_lo = b.parts.frac_lo;312 exp1 = b.parts.exp;313 frac2_hi = a.parts.frac_hi;314 frac2_lo = a.parts.frac_lo;315 exp2 = a.parts.exp;316 expdiff *= -1;317 } else {318 if (isFloat128NaN(a)) {319 /* TODO: fix SigNaN */320 if (isFloat128SigNaN(a) || isFloat128SigNaN(b)) {321 }322 return a;323 }324 325 if (a.parts.exp == FLOAT128_MAX_EXPONENT) {326 if (b.parts.exp == FLOAT128_MAX_EXPONENT) {327 /* inf - inf => nan */328 /* TODO: fix exception */329 result.binary.hi = FLOAT128_NAN_HI;330 result.binary.lo = FLOAT128_NAN_LO;331 return result;332 }333 return a;334 }335 336 result.parts.sign = a.parts.sign;337 338 frac1_hi = a.parts.frac_hi;339 frac1_lo = a.parts.frac_lo;340 exp1 = a.parts.exp;341 frac2_hi = b.parts.frac_hi;342 frac2_lo = b.parts.frac_lo;343 exp2 = b.parts.exp;344 }345 346 if (exp1 == 0) {347 /* both are denormalized */348 sub128(frac1_hi, frac1_lo, frac2_hi, frac2_lo, &tmp_hi, &tmp_lo);349 result.parts.frac_hi = tmp_hi;350 result.parts.frac_lo = tmp_lo;351 if (lt128(frac1_hi, frac1_lo, result.parts.frac_hi, result.parts.frac_lo)) {352 /* TODO: underflow exception */353 return result;354 }355 result.parts.exp = 0;356 return result;357 }358 359 /* add hidden bit */360 or128(frac1_hi, frac1_lo,361 FLOAT128_HIDDEN_BIT_MASK_HI, FLOAT128_HIDDEN_BIT_MASK_LO,362 &frac1_hi, &frac1_lo);363 364 if (exp2 == 0) {365 /* denormalized */366 --expdiff;367 } else {368 /* normalized */369 or128(frac2_hi, frac2_lo,370 FLOAT128_HIDDEN_BIT_MASK_HI, FLOAT128_HIDDEN_BIT_MASK_LO,371 &frac2_hi, &frac2_lo);372 }373 374 /* create some space for rounding */375 lshift128(frac1_hi, frac1_lo, 6, &frac1_hi, &frac1_lo);376 lshift128(frac2_hi, frac2_lo, 6, &frac2_hi, &frac2_lo);377 378 if (expdiff > FLOAT128_FRACTION_SIZE + 1) {379 goto done;380 }381 382 rshift128(frac2_hi, frac2_lo, expdiff, &tmp_hi, &tmp_lo);383 sub128(frac1_hi, frac1_lo, tmp_hi, tmp_lo, &frac1_hi, &frac1_lo);384 385 done:386 /* TODO: find first nonzero digit and shift result and detect possibly underflow */387 lshift128(FLOAT128_HIDDEN_BIT_MASK_HI, FLOAT128_HIDDEN_BIT_MASK_LO, 6,388 &tmp_hi, &tmp_lo);389 and128(frac1_hi, frac1_lo, tmp_hi, tmp_lo, &tmp_hi, &tmp_lo);390 while ((exp1 > 0) && (!lt128(0x0ll, 0x0ll, tmp_hi, tmp_lo))) {391 --exp1;392 lshift128(frac1_hi, frac1_lo, 1, &frac1_hi, &frac1_lo);393 /* TODO: fix underflow - frac1 == 0 does not necessary means underflow... */394 395 lshift128(FLOAT128_HIDDEN_BIT_MASK_HI, FLOAT128_HIDDEN_BIT_MASK_LO, 6,396 &tmp_hi, &tmp_lo);397 and128(frac1_hi, frac1_lo, tmp_hi, tmp_lo, &tmp_hi, &tmp_lo);398 }399 400 /* rounding - if first bit after fraction is set then round up */401 add128(frac1_hi, frac1_lo, 0x0ll, 0x20ll, &frac1_hi, &frac1_lo);402 403 lshift128(FLOAT128_HIDDEN_BIT_MASK_HI, FLOAT128_HIDDEN_BIT_MASK_LO, 7,404 &tmp_hi, &tmp_lo);405 and128(frac1_hi, frac1_lo, tmp_hi, tmp_lo, &tmp_hi, &tmp_lo);406 if (lt128(0x0ll, 0x0ll, tmp_hi, tmp_lo)) {407 ++exp1;408 rshift128(frac1_hi, frac1_lo, 1, &frac1_hi, &frac1_lo);409 }410 411 /* Clear hidden bit and shift */412 rshift128(frac1_hi, frac1_lo, 6, &frac1_hi, &frac1_lo);413 not128(FLOAT128_HIDDEN_BIT_MASK_HI, FLOAT128_HIDDEN_BIT_MASK_LO,414 &tmp_hi, &tmp_lo);415 and128(frac1_hi, frac1_lo, tmp_hi, tmp_lo, &tmp_hi, &tmp_lo);416 result.parts.frac_hi = tmp_hi;417 result.parts.frac_lo = tmp_lo;418 419 result.parts.exp = exp1;420 421 return result;422 }423 424 262 /** @} 425 263 */
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