1 2 /*============================================================================ 3 4 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic 5 Package, Release 3e, 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 #ifdef SOFTFLOAT_FAST_INT64 45 46 void extF80M_rem(const extFloat80_t * aPtr,const extFloat80_t * bPtr,extFloat80_t * zPtr)47 extF80M_rem( 48 const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr ) 49 { 50 51 *zPtr = extF80_rem( *aPtr, *bPtr ); 52 53 } 54 55 #else 56 57 void extF80M_rem(const extFloat80_t * aPtr,const extFloat80_t * bPtr,extFloat80_t * zPtr)58 extF80M_rem( 59 const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr ) 60 { 61 const struct extFloat80M *aSPtr, *bSPtr; 62 struct extFloat80M *zSPtr; 63 uint_fast16_t uiA64; 64 int32_t expA, expB; 65 uint64_t x64; 66 bool signRem; 67 uint64_t sigA; 68 int32_t expDiff; 69 uint32_t rem[3], x[3], sig32B, q, recip32, rem2[3], *remPtr, *altRemPtr; 70 uint32_t *newRemPtr, wordMeanRem; 71 72 /*------------------------------------------------------------------------ 73 *------------------------------------------------------------------------*/ 74 aSPtr = (const struct extFloat80M *) aPtr; 75 bSPtr = (const struct extFloat80M *) bPtr; 76 zSPtr = (struct extFloat80M *) zPtr; 77 /*------------------------------------------------------------------------ 78 *------------------------------------------------------------------------*/ 79 uiA64 = aSPtr->signExp; 80 expA = expExtF80UI64( uiA64 ); 81 expB = expExtF80UI64( bSPtr->signExp ); 82 /*------------------------------------------------------------------------ 83 *------------------------------------------------------------------------*/ 84 if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) { 85 if ( softfloat_tryPropagateNaNExtF80M( aSPtr, bSPtr, zSPtr ) ) return; 86 if ( expA == 0x7FFF ) goto invalid; 87 /*-------------------------------------------------------------------- 88 | If we get here, then argument b is an infinity and `expB' is 0x7FFF; 89 | Doubling `expB' is an easy way to ensure that `expDiff' later is 90 | less than -1, which will result in returning a canonicalized version 91 | of argument a. 92 *--------------------------------------------------------------------*/ 93 expB += expB; 94 } 95 /*------------------------------------------------------------------------ 96 *------------------------------------------------------------------------*/ 97 if ( ! expB ) expB = 1; 98 x64 = bSPtr->signif; 99 if ( ! (x64 & UINT64_C( 0x8000000000000000 )) ) { 100 if ( ! x64 ) goto invalid; 101 expB += softfloat_normExtF80SigM( &x64 ); 102 } 103 signRem = signExtF80UI64( uiA64 ); 104 if ( ! expA ) expA = 1; 105 sigA = aSPtr->signif; 106 if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) { 107 if ( ! sigA ) { 108 expA = 0; 109 goto copyA; 110 } 111 expA += softfloat_normExtF80SigM( &sigA ); 112 } 113 /*------------------------------------------------------------------------ 114 *------------------------------------------------------------------------*/ 115 expDiff = expA - expB; 116 if ( expDiff < -1 ) goto copyA; 117 rem[indexWord( 3, 2 )] = sigA>>34; 118 rem[indexWord( 3, 1 )] = sigA>>2; 119 rem[indexWord( 3, 0 )] = (uint32_t) sigA<<30; 120 x[indexWord( 3, 0 )] = (uint32_t) x64<<30; 121 sig32B = x64>>32; 122 x64 >>= 2; 123 x[indexWord( 3, 2 )] = x64>>32; 124 x[indexWord( 3, 1 )] = x64; 125 if ( expDiff < 1 ) { 126 if ( expDiff ) { 127 --expB; 128 softfloat_add96M( x, x, x ); 129 q = 0; 130 } else { 131 q = (softfloat_compare96M( x, rem ) <= 0); 132 if ( q ) softfloat_sub96M( rem, x, rem ); 133 } 134 } else { 135 recip32 = softfloat_approxRecip32_1( sig32B ); 136 expDiff -= 30; 137 for (;;) { 138 x64 = (uint64_t) rem[indexWordHi( 3 )] * recip32; 139 if ( expDiff < 0 ) break; 140 q = (x64 + 0x80000000)>>32; 141 softfloat_remStep96MBy32( rem, 29, x, q, rem ); 142 if ( rem[indexWordHi( 3 )] & 0x80000000 ) { 143 softfloat_add96M( rem, x, rem ); 144 } 145 expDiff -= 29; 146 } 147 /*-------------------------------------------------------------------- 148 | (`expDiff' cannot be less than -29 here.) 149 *--------------------------------------------------------------------*/ 150 q = (uint32_t) (x64>>32)>>(~expDiff & 31); 151 softfloat_remStep96MBy32( rem, expDiff + 30, x, q, rem ); 152 if ( rem[indexWordHi( 3 )] & 0x80000000 ) { 153 remPtr = rem; 154 altRemPtr = rem2; 155 softfloat_add96M( remPtr, x, altRemPtr ); 156 goto selectRem; 157 } 158 } 159 /*------------------------------------------------------------------------ 160 *------------------------------------------------------------------------*/ 161 remPtr = rem; 162 altRemPtr = rem2; 163 do { 164 ++q; 165 newRemPtr = altRemPtr; 166 softfloat_sub96M( remPtr, x, newRemPtr ); 167 altRemPtr = remPtr; 168 remPtr = newRemPtr; 169 } while ( ! (remPtr[indexWordHi( 3 )] & 0x80000000) ); 170 selectRem: 171 softfloat_add96M( remPtr, altRemPtr, x ); 172 wordMeanRem = x[indexWordHi( 3 )]; 173 if ( 174 (wordMeanRem & 0x80000000) 175 || (! wordMeanRem && (q & 1) && ! x[indexWord( 3, 0 )] 176 && ! x[indexWord( 3, 1 )]) 177 ) { 178 remPtr = altRemPtr; 179 } 180 if ( remPtr[indexWordHi( 3 )] & 0x80000000 ) { 181 signRem = ! signRem; 182 softfloat_negX96M( remPtr ); 183 } 184 softfloat_normRoundPackMToExtF80M( signRem, expB + 2, remPtr, 80, zSPtr ); 185 return; 186 /*------------------------------------------------------------------------ 187 *------------------------------------------------------------------------*/ 188 invalid: 189 softfloat_invalidExtF80M( zSPtr ); 190 return; 191 /*------------------------------------------------------------------------ 192 *------------------------------------------------------------------------*/ 193 copyA: 194 if ( expA < 1 ) { 195 sigA >>= 1 - expA; 196 expA = 0; 197 } 198 zSPtr->signExp = packToExtF80UI64( signRem, expA ); 199 zSPtr->signif = sigA; 200 201 } 202 203 #endif 204 205