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 "softfloat.h" 43 44 void softfloat_roundPackMToF128M(bool sign,int32_t exp,uint32_t * extSigPtr,uint32_t * zWPtr)45 softfloat_roundPackMToF128M( 46 bool sign, int32_t exp, uint32_t *extSigPtr, uint32_t *zWPtr ) 47 { 48 uint_fast8_t roundingMode; 49 bool roundNearEven; 50 uint32_t sigExtra; 51 bool doIncrement, isTiny; 52 static const uint32_t maxSig[4] = 53 INIT_UINTM4( 0x0001FFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF ); 54 uint32_t ui, uj; 55 56 roundingMode = softfloat_roundingMode; 57 roundNearEven = (roundingMode == softfloat_round_near_even); 58 sigExtra = extSigPtr[indexWordLo( 5 )]; 59 doIncrement = (0x80000000 <= sigExtra); 60 if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { 61 doIncrement = 62 (roundingMode 63 == (sign ? softfloat_round_min : softfloat_round_max)) 64 && sigExtra; 65 } 66 if ( 0x7FFD <= (uint32_t) exp ) { 67 if ( exp < 0 ) { 68 isTiny = 69 (softfloat_detectTininess 70 == softfloat_tininess_beforeRounding) 71 || (exp < -1) 72 || ! doIncrement 73 || (softfloat_compare128M( 74 extSigPtr + indexMultiwordHi( 5, 4 ), maxSig ) 75 < 0); 76 softfloat_shiftRightJam160M( extSigPtr, -exp, extSigPtr ); 77 exp = 0; 78 sigExtra = extSigPtr[indexWordLo( 5 )]; 79 if ( isTiny && sigExtra ) { 80 softfloat_raiseFlags( softfloat_flag_underflow ); 81 } 82 doIncrement = (0x80000000 <= sigExtra); 83 if ( 84 ! roundNearEven 85 && (roundingMode != softfloat_round_near_maxMag) 86 ) { 87 doIncrement = 88 (roundingMode 89 == (sign ? softfloat_round_min : softfloat_round_max)) 90 && sigExtra; 91 } 92 } else if ( 93 (0x7FFD < exp) 94 || ((exp == 0x7FFD) && doIncrement 95 && (softfloat_compare128M( 96 extSigPtr + indexMultiwordHi( 5, 4 ), maxSig ) 97 == 0)) 98 ) { 99 softfloat_raiseFlags( 100 softfloat_flag_overflow | softfloat_flag_inexact ); 101 if ( 102 roundNearEven 103 || (roundingMode == softfloat_round_near_maxMag) 104 || (roundingMode 105 == (sign ? softfloat_round_min : softfloat_round_max)) 106 ) { 107 ui = packToF128UI96( sign, 0x7FFF, 0 ); 108 uj = 0; 109 } else { 110 ui = packToF128UI96( sign, 0x7FFE, 0x0000FFFF ); 111 uj = 0xFFFFFFFF; 112 } 113 zWPtr[indexWordHi( 4 )] = ui; 114 zWPtr[indexWord( 4, 2 )] = uj; 115 zWPtr[indexWord( 4, 1 )] = uj; 116 zWPtr[indexWord( 4, 0 )] = uj; 117 return; 118 } 119 } 120 if ( sigExtra ) softfloat_exceptionFlags |= softfloat_flag_inexact; 121 uj = extSigPtr[indexWord( 5, 1 )]; 122 if ( doIncrement ) { 123 ++uj; 124 if ( uj ) { 125 if ( ! (sigExtra & 0x7FFFFFFF) && roundNearEven ) uj &= ~1; 126 zWPtr[indexWord( 4, 2 )] = extSigPtr[indexWord( 5, 3 )]; 127 zWPtr[indexWord( 4, 1 )] = extSigPtr[indexWord( 5, 2 )]; 128 zWPtr[indexWord( 4, 0 )] = uj; 129 ui = extSigPtr[indexWordHi( 5 )]; 130 } else { 131 zWPtr[indexWord( 4, 0 )] = uj; 132 ui = extSigPtr[indexWord( 5, 2 )] + 1; 133 zWPtr[indexWord( 4, 1 )] = ui; 134 uj = extSigPtr[indexWord( 5, 3 )]; 135 if ( ui ) { 136 zWPtr[indexWord( 4, 2 )] = uj; 137 ui = extSigPtr[indexWordHi( 5 )]; 138 } else { 139 ++uj; 140 zWPtr[indexWord( 4, 2 )] = uj; 141 ui = extSigPtr[indexWordHi( 5 )]; 142 if ( ! uj ) ++ui; 143 } 144 } 145 } else { 146 zWPtr[indexWord( 4, 0 )] = uj; 147 ui = extSigPtr[indexWord( 5, 2 )]; 148 zWPtr[indexWord( 4, 1 )] = ui; 149 uj |= ui; 150 ui = extSigPtr[indexWord( 5, 3 )]; 151 zWPtr[indexWord( 4, 2 )] = ui; 152 uj |= ui; 153 ui = extSigPtr[indexWordHi( 5 )]; 154 uj |= ui; 155 if ( ! uj ) exp = 0; 156 } 157 zWPtr[indexWordHi( 4 )] = packToF128UI96( sign, exp, ui ); 158 159 } 160 161