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, 2015 The Regents of the University of 8 California. 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_sqrt( const extFloat80_t *aPtr, extFloat80_t *zPtr ) 47 { 48 49 *zPtr = extF80_sqrt( *aPtr ); 50 51 } 52 53 #else 54 55 void extF80M_sqrt( const extFloat80_t *aPtr, extFloat80_t *zPtr ) 56 { 57 const struct extFloat80M *aSPtr; 58 struct extFloat80M *zSPtr; 59 uint_fast16_t uiA64, signUI64; 60 int32_t expA; 61 uint64_t rem64; 62 int32_t expZ; 63 uint32_t rem[4], sig32A, recipSqrt32, sig32Z, q; 64 uint64_t sig64Z, x64; 65 uint32_t term[4], extSigZ[3]; 66 67 /*------------------------------------------------------------------------ 68 *------------------------------------------------------------------------*/ 69 aSPtr = (const struct extFloat80M *) aPtr; 70 zSPtr = (struct extFloat80M *) zPtr; 71 /*------------------------------------------------------------------------ 72 *------------------------------------------------------------------------*/ 73 uiA64 = aSPtr->signExp; 74 signUI64 = uiA64 & packToExtF80UI64( 1, 0 ); 75 expA = expExtF80UI64( uiA64 ); 76 rem64 = aSPtr->signif; 77 /*------------------------------------------------------------------------ 78 *------------------------------------------------------------------------*/ 79 if ( expA == 0x7FFF ) { 80 if ( rem64 & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) { 81 softfloat_propagateNaNExtF80M( aSPtr, 0, zSPtr ); 82 return; 83 } 84 if ( signUI64 ) goto invalid; 85 rem64 = UINT64_C( 0x8000000000000000 ); 86 goto copyA; 87 } 88 /*------------------------------------------------------------------------ 89 *------------------------------------------------------------------------*/ 90 if ( ! expA ) expA = 1; 91 if ( ! (rem64 & UINT64_C( 0x8000000000000000 )) ) { 92 if ( ! rem64 ) { 93 uiA64 = signUI64; 94 goto copyA; 95 } 96 expA += softfloat_normExtF80SigM( &rem64 ); 97 } 98 if ( signUI64 ) goto invalid; 99 /*------------------------------------------------------------------------ 100 *------------------------------------------------------------------------*/ 101 expZ = ((expA - 0x3FFF)>>1) + 0x3FFF; 102 expA &= 1; 103 softfloat_shortShiftLeft64To96M( 104 rem64, 30 - expA, &rem[indexMultiwordHi( 4, 3 )] ); 105 sig32A = rem64>>32; 106 recipSqrt32 = softfloat_approxRecipSqrt32_1( expA, sig32A ); 107 sig32Z = ((uint64_t) sig32A * recipSqrt32)>>32; 108 if ( expA ) sig32Z >>= 1; 109 rem64 = 110 ((uint64_t) rem[indexWord( 4, 3 )]<<32 | rem[indexWord( 4, 2 )]) 111 - (uint64_t) sig32Z * sig32Z; 112 rem[indexWord( 4, 3 )] = rem64>>32; 113 rem[indexWord( 4, 2 )] = rem64; 114 /*------------------------------------------------------------------------ 115 *------------------------------------------------------------------------*/ 116 q = ((uint32_t) (rem64>>2) * (uint64_t) recipSqrt32)>>32; 117 sig64Z = ((uint64_t) sig32Z<<32) + ((uint64_t) q<<3); 118 x64 = ((uint64_t) sig32Z<<32) + sig64Z; 119 term[indexWord( 3, 2 )] = 0; 120 term[indexWord( 3, 1 )] = x64>>32; 121 term[indexWord( 3, 0 )] = x64; 122 softfloat_remStep96MBy32( 123 &rem[indexMultiwordHi( 4, 3 )], 124 29, 125 term, 126 q, 127 &rem[indexMultiwordHi( 4, 3 )] 128 ); 129 rem64 = (uint64_t) rem[indexWord( 4, 3 )]<<32 | rem[indexWord( 4, 2 )]; 130 /*------------------------------------------------------------------------ 131 *------------------------------------------------------------------------*/ 132 q = (((uint32_t) (rem64>>2) * (uint64_t) recipSqrt32)>>32) + 2; 133 x64 = (uint64_t) q<<7; 134 extSigZ[indexWord( 3, 0 )] = x64; 135 x64 = (sig64Z<<1) + (x64>>32); 136 extSigZ[indexWord( 3, 2 )] = x64>>32; 137 extSigZ[indexWord( 3, 1 )] = x64; 138 /*------------------------------------------------------------------------ 139 *------------------------------------------------------------------------*/ 140 if ( (q & 0xFFFFFF) <= 2 ) { 141 q &= ~(uint32_t) 0xFFFF; 142 extSigZ[indexWordLo( 3 )] = q<<7; 143 x64 = sig64Z + (q>>27); 144 term[indexWord( 4, 3 )] = 0; 145 term[indexWord( 4, 2 )] = x64>>32; 146 term[indexWord( 4, 1 )] = x64; 147 term[indexWord( 4, 0 )] = q<<5; 148 rem[indexWord( 4, 0 )] = 0; 149 softfloat_remStep128MBy32( rem, 28, term, q, rem ); 150 q = rem[indexWordHi( 4 )]; 151 if ( q & 0x80000000 ) { 152 softfloat_sub1X96M( extSigZ ); 153 } else { 154 if ( q || rem[indexWord( 4, 1 )] || rem[indexWord( 4, 2 )] ) { 155 extSigZ[indexWordLo( 3 )] |= 1; 156 } 157 } 158 } 159 softfloat_roundPackMToExtF80M( 160 0, expZ, extSigZ, extF80_roundingPrecision, zSPtr ); 161 return; 162 /*------------------------------------------------------------------------ 163 *------------------------------------------------------------------------*/ 164 invalid: 165 softfloat_invalidExtF80M( zSPtr ); 166 return; 167 /*------------------------------------------------------------------------ 168 *------------------------------------------------------------------------*/ 169 copyA: 170 zSPtr->signExp = uiA64; 171 zSPtr->signif = rem64; 172 173 } 174 175 #endif 176 177