1 2 /*============================================================================ 3 4 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic 5 Package, Release 3a, by John R. Hauser. 6 7 Copyright 2011, 2012, 2013, 2014 The Regents of the University of California. 8 All rights reserved. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions are met: 12 13 1. Redistributions of source code must retain the above copyright notice, 14 this list of conditions, and the following disclaimer. 15 16 2. Redistributions in binary form must reproduce the above copyright notice, 17 this list of conditions, and the following disclaimer in the documentation 18 and/or other materials provided with the distribution. 19 20 3. Neither the name of the University nor the names of its contributors may 21 be used to endorse or promote products derived from this software without 22 specific prior written permission. 23 24 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY 25 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 26 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE 27 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY 28 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 29 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 31 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 35 =============================================================================*/ 36 37 #include <stdbool.h> 38 #include <stdint.h> 39 #include "platform.h" 40 #include "internals.h" 41 #include "specialize.h" 42 #include "softfloat.h" 43 44 float32_t 45 softfloat_mulAddF32( 46 uint_fast32_t uiA, uint_fast32_t uiB, uint_fast32_t uiC, uint_fast8_t op ) 47 { 48 bool signA; 49 int_fast16_t expA; 50 uint_fast32_t sigA; 51 bool signB; 52 int_fast16_t expB; 53 uint_fast32_t sigB; 54 bool signC; 55 int_fast16_t expC; 56 uint_fast32_t sigC; 57 bool signProd; 58 uint_fast32_t magBits, uiZ; 59 struct exp16_sig32 normExpSig; 60 int_fast16_t expProd; 61 uint_fast64_t sigProd; 62 bool signZ; 63 int_fast16_t expZ; 64 uint_fast32_t sigZ; 65 int_fast16_t expDiff; 66 uint_fast64_t sig64Z, sig64C; 67 int_fast8_t shiftCount; 68 union ui32_f32 uZ; 69 70 signA = signF32UI( uiA ); 71 expA = expF32UI( uiA ); 72 sigA = fracF32UI( uiA ); 73 signB = signF32UI( uiB ); 74 expB = expF32UI( uiB ); 75 sigB = fracF32UI( uiB ); 76 signC = signF32UI( uiC ) ^ (op == softfloat_mulAdd_subC); 77 expC = expF32UI( uiC ); 78 sigC = fracF32UI( uiC ); 79 signProd = signA ^ signB ^ (op == softfloat_mulAdd_subProd); 80 if ( expA == 0xFF ) { 81 if ( sigA || ((expB == 0xFF) && sigB) ) goto propagateNaN_ABC; 82 magBits = expB | sigB; 83 goto infProdArg; 84 } 85 if ( expB == 0xFF ) { 86 if ( sigB ) goto propagateNaN_ABC; 87 magBits = expA | sigA; 88 goto infProdArg; 89 } 90 if ( expC == 0xFF ) { 91 if ( sigC ) { 92 uiZ = 0; 93 goto propagateNaN_ZC; 94 } 95 uiZ = uiC; 96 goto uiZ; 97 } 98 if ( ! expA ) { 99 if ( ! sigA ) goto zeroProd; 100 normExpSig = softfloat_normSubnormalF32Sig( sigA ); 101 expA = normExpSig.exp; 102 sigA = normExpSig.sig; 103 } 104 if ( ! expB ) { 105 if ( ! sigB ) goto zeroProd; 106 normExpSig = softfloat_normSubnormalF32Sig( sigB ); 107 expB = normExpSig.exp; 108 sigB = normExpSig.sig; 109 } 110 expProd = expA + expB - 0x7E; 111 sigA = (sigA | 0x00800000)<<7; 112 sigB = (sigB | 0x00800000)<<7; 113 sigProd = (uint_fast64_t) sigA * sigB; 114 if ( sigProd < UINT64_C( 0x2000000000000000 ) ) { 115 --expProd; 116 sigProd <<= 1; 117 } 118 signZ = signProd; 119 if ( ! expC ) { 120 if ( ! sigC ) { 121 expZ = expProd - 1; 122 sigZ = softfloat_shortShiftRightJam64( sigProd, 31 ); 123 goto roundPack; 124 } 125 normExpSig = softfloat_normSubnormalF32Sig( sigC ); 126 expC = normExpSig.exp; 127 sigC = normExpSig.sig; 128 } 129 sigC = (sigC | 0x00800000)<<6; 130 expDiff = expProd - expC; 131 if ( signProd == signC ) { 132 if ( expDiff <= 0 ) { 133 expZ = expC; 134 sigZ = sigC + softfloat_shiftRightJam64( sigProd, 32 - expDiff ); 135 } else { 136 expZ = expProd; 137 sig64Z = 138 sigProd 139 + softfloat_shiftRightJam64( 140 (uint_fast64_t) sigC<<32, expDiff ); 141 sigZ = softfloat_shortShiftRightJam64( sig64Z, 32 ); 142 } 143 if ( sigZ < 0x40000000 ) { 144 --expZ; 145 sigZ <<= 1; 146 } 147 } else { 148 sig64C = (uint_fast64_t) sigC<<32; 149 if ( expDiff < 0 ) { 150 signZ = signC; 151 expZ = expC; 152 sig64Z = sig64C - softfloat_shiftRightJam64( sigProd, -expDiff ); 153 } else if ( ! expDiff ) { 154 expZ = expProd; 155 sig64Z = sigProd - sig64C; 156 if ( ! sig64Z ) goto completeCancellation; 157 if ( sig64Z & UINT64_C( 0x8000000000000000 ) ) { 158 signZ ^= 1; 159 sig64Z = -sig64Z; 160 } 161 } else { 162 expZ = expProd; 163 sig64Z = sigProd - softfloat_shiftRightJam64( sig64C, expDiff ); 164 } 165 shiftCount = softfloat_countLeadingZeros64( sig64Z ) - 1; 166 expZ -= shiftCount; 167 shiftCount -= 32; 168 if ( shiftCount < 0 ) { 169 sigZ = softfloat_shortShiftRightJam64( sig64Z, -shiftCount ); 170 } else { 171 sigZ = (uint_fast32_t) sig64Z<<shiftCount; 172 } 173 } 174 roundPack: 175 return softfloat_roundPackToF32( signZ, expZ, sigZ ); 176 propagateNaN_ABC: 177 uiZ = softfloat_propagateNaNF32UI( uiA, uiB ); 178 goto propagateNaN_ZC; 179 infProdArg: 180 if ( magBits ) { 181 uiZ = packToF32UI( signProd, 0xFF, 0 ); 182 if ( expC != 0xFF ) goto uiZ; 183 if ( sigC ) goto propagateNaN_ZC; 184 if ( signProd == signC ) goto uiZ; 185 } 186 invalid: 187 softfloat_raiseFlags( softfloat_flag_invalid ); 188 uiZ = defaultNaNF32UI; 189 propagateNaN_ZC: 190 uiZ = softfloat_propagateNaNF32UI( uiZ, uiC ); 191 goto uiZ; 192 zeroProd: 193 uiZ = uiC; 194 if ( ! (expC | sigC) && (signProd != signC) ) { 195 completeCancellation: 196 uiZ = 197 packToF32UI( softfloat_roundingMode == softfloat_round_min, 0, 0 ); 198 } 199 uiZ: 200 uZ.ui = uiZ; 201 return uZ.f; 202 203 } 204 205