1 // SPDX-License-Identifier: BSD-3-Clause 2 3 /*============================================================================ 4 5 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic 6 Package, Release 3a, by John R. Hauser. 7 8 Copyright 2011, 2012, 2013, 2014 The Regents of the University of California. 9 All rights reserved. 10 11 Redistribution and use in source and binary forms, with or without 12 modification, are permitted provided that the following conditions are met: 13 14 1. Redistributions of source code must retain the above copyright notice, 15 this list of conditions, and the following disclaimer. 16 17 2. Redistributions in binary form must reproduce the above copyright notice, 18 this list of conditions, and the following disclaimer in the documentation 19 and/or other materials provided with the distribution. 20 21 3. Neither the name of the University nor the names of its contributors may 22 be used to endorse or promote products derived from this software without 23 specific prior written permission. 24 25 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY 26 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 27 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE 28 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY 29 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 30 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 32 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 34 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 36 =============================================================================*/ 37 38 #include <stdbool.h> 39 #include <stdint.h> 40 #include "platform.h" 41 #include "internals.h" 42 #include "specialize.h" 43 #include "softfloat.h" 44 45 #ifdef SOFTFLOAT_FAST_INT64 46 47 void extF80M_rem(const extFloat80_t * aPtr,const extFloat80_t * bPtr,extFloat80_t * zPtr)48 extF80M_rem( 49 const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr ) 50 { 51 52 *zPtr = extF80_rem( *aPtr, *bPtr ); 53 54 } 55 56 #else 57 58 void extF80M_rem(const extFloat80_t * aPtr,const extFloat80_t * bPtr,extFloat80_t * zPtr)59 extF80M_rem( 60 const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr ) 61 { 62 const struct extFloat80M *aSPtr, *bSPtr; 63 struct extFloat80M *zSPtr; 64 uint_fast16_t uiA64; 65 int32_t expA, expB; 66 uint64_t x64; 67 bool signRem; 68 uint64_t sigA; 69 int32_t expDiff; 70 uint32_t rem[3], x[3], sig32B, q, recip32, rem2[3], *remPtr, *altRemPtr; 71 uint32_t *newRemPtr, wordMeanRem; 72 73 /*------------------------------------------------------------------------ 74 *------------------------------------------------------------------------*/ 75 aSPtr = (const struct extFloat80M *) aPtr; 76 bSPtr = (const struct extFloat80M *) bPtr; 77 zSPtr = (struct extFloat80M *) zPtr; 78 /*------------------------------------------------------------------------ 79 *------------------------------------------------------------------------*/ 80 uiA64 = aSPtr->signExp; 81 expA = expExtF80UI64( uiA64 ); 82 expB = expExtF80UI64( bSPtr->signExp ); 83 /*------------------------------------------------------------------------ 84 *------------------------------------------------------------------------*/ 85 if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) { 86 if ( softfloat_tryPropagateNaNExtF80M( aSPtr, bSPtr, zSPtr ) ) return; 87 if ( expA == 0x7FFF ) goto invalid; 88 /*-------------------------------------------------------------------- 89 | If we get here, then argument b is an infinity and `expB' is 0x7FFF; 90 | Doubling `expB' is an easy way to ensure that `expDiff' later is 91 | less than -1, which will result in returning a canonicalized version 92 | of argument a. 93 *--------------------------------------------------------------------*/ 94 expB += expB; 95 } 96 /*------------------------------------------------------------------------ 97 *------------------------------------------------------------------------*/ 98 if ( ! expB ) expB = 1; 99 x64 = bSPtr->signif; 100 if ( ! (x64 & UINT64_C( 0x8000000000000000 )) ) { 101 if ( ! x64 ) goto invalid; 102 expB += softfloat_normExtF80SigM( &x64 ); 103 } 104 signRem = signExtF80UI64( uiA64 ); 105 if ( ! expA ) expA = 1; 106 sigA = aSPtr->signif; 107 if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) { 108 if ( ! sigA ) { 109 expA = 0; 110 goto copyA; 111 } 112 expA += softfloat_normExtF80SigM( &sigA ); 113 } 114 /*------------------------------------------------------------------------ 115 *------------------------------------------------------------------------*/ 116 expDiff = expA - expB; 117 if ( expDiff < -1 ) goto copyA; 118 rem[indexWord( 3, 2 )] = sigA>>34; 119 rem[indexWord( 3, 1 )] = sigA>>2; 120 rem[indexWord( 3, 0 )] = (uint32_t) sigA<<30; 121 x[indexWord( 3, 0 )] = (uint32_t) x64<<30; 122 sig32B = x64>>32; 123 x64 >>= 2; 124 x[indexWord( 3, 2 )] = x64>>32; 125 x[indexWord( 3, 1 )] = x64; 126 if ( expDiff < 1 ) { 127 if ( expDiff ) { 128 --expB; 129 softfloat_add96M( x, x, x ); 130 q = 0; 131 } else { 132 q = (softfloat_compare96M( x, rem ) <= 0); 133 if ( q ) softfloat_sub96M( rem, x, rem ); 134 } 135 } else { 136 recip32 = softfloat_approxRecip32_1( sig32B ); 137 expDiff -= 30; 138 for (;;) { 139 x64 = (uint64_t) rem[indexWordHi( 3 )] * recip32; 140 if ( expDiff < 0 ) break; 141 q = (x64 + 0x80000000)>>32; 142 softfloat_remStep96MBy32( rem, 29, x, q, rem ); 143 if ( rem[indexWordHi( 3 )] & 0x80000000 ) { 144 softfloat_add96M( rem, x, rem ); 145 } 146 expDiff -= 29; 147 } 148 /*-------------------------------------------------------------------- 149 | (`expDiff' cannot be less than -29 here.) 150 *--------------------------------------------------------------------*/ 151 q = (uint32_t) (x64>>32)>>(~expDiff & 31); 152 softfloat_remStep96MBy32( rem, expDiff + 30, x, q, rem ); 153 if ( rem[indexWordHi( 3 )] & 0x80000000 ) { 154 remPtr = rem; 155 altRemPtr = rem2; 156 softfloat_add96M( remPtr, x, altRemPtr ); 157 goto selectRem; 158 } 159 } 160 /*------------------------------------------------------------------------ 161 *------------------------------------------------------------------------*/ 162 remPtr = rem; 163 altRemPtr = rem2; 164 do { 165 ++q; 166 newRemPtr = altRemPtr; 167 softfloat_sub96M( remPtr, x, newRemPtr ); 168 altRemPtr = remPtr; 169 remPtr = newRemPtr; 170 } while ( ! (remPtr[indexWordHi( 3 )] & 0x80000000) ); 171 selectRem: 172 softfloat_add96M( remPtr, altRemPtr, x ); 173 wordMeanRem = x[indexWordHi( 3 )]; 174 if ( 175 (wordMeanRem & 0x80000000) 176 || (! wordMeanRem && (q & 1) && ! x[indexWord( 3, 0 )] 177 && ! x[indexWord( 3, 1 )]) 178 ) { 179 remPtr = altRemPtr; 180 } 181 if ( remPtr[indexWordHi( 3 )] & 0x80000000 ) { 182 signRem = ! signRem; 183 softfloat_negX96M( remPtr ); 184 } 185 softfloat_normRoundPackMToExtF80M( signRem, expB + 2, remPtr, 80, zSPtr ); 186 return; 187 /*------------------------------------------------------------------------ 188 *------------------------------------------------------------------------*/ 189 invalid: 190 softfloat_invalidExtF80M( zSPtr ); 191 return; 192 /*------------------------------------------------------------------------ 193 *------------------------------------------------------------------------*/ 194 copyA: 195 if ( expA < 1 ) { 196 sigA >>= 1 - expA; 197 expA = 0; 198 } 199 zSPtr->signExp = packToExtF80UI64( signRem, expA ); 200 zSPtr->signif = sigA; 201 202 } 203 204 #endif 205 206