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 "softfloat.h" 42 43 void 44 softfloat_roundPackMToF128M( 45 bool sign, int32_t exp, uint32_t *extSigPtr, uint32_t *zWPtr ) 46 { 47 uint_fast8_t roundingMode; 48 bool roundNearEven; 49 uint32_t sigExtra; 50 bool doIncrement, isTiny; 51 static const uint32_t maxSig[4] = 52 INIT_UINTM4( 0x0001FFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF ); 53 uint32_t ui, uj; 54 55 roundingMode = softfloat_roundingMode; 56 roundNearEven = (roundingMode == softfloat_round_near_even); 57 sigExtra = extSigPtr[indexWordLo( 5 )]; 58 doIncrement = (0x80000000 <= sigExtra); 59 if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { 60 doIncrement = 61 (roundingMode 62 == (sign ? softfloat_round_min : softfloat_round_max)) 63 && sigExtra; 64 } 65 if ( 0x7FFD <= (uint32_t) exp ) { 66 if ( exp < 0 ) { 67 isTiny = 68 (softfloat_detectTininess 69 == softfloat_tininess_beforeRounding) 70 || (exp < -1) 71 || ! doIncrement 72 || (softfloat_compare128M( 73 extSigPtr + indexMultiwordHi( 5, 4 ), maxSig ) 74 < 0); 75 softfloat_shiftRightJam160M( extSigPtr, -exp, extSigPtr ); 76 exp = 0; 77 sigExtra = extSigPtr[indexWordLo( 5 )]; 78 if ( isTiny && sigExtra ) { 79 softfloat_raiseFlags( softfloat_flag_underflow ); 80 } 81 doIncrement = (0x80000000 <= sigExtra); 82 if ( 83 ! roundNearEven 84 && (roundingMode != softfloat_round_near_maxMag) 85 ) { 86 doIncrement = 87 (roundingMode 88 == (sign ? softfloat_round_min : softfloat_round_max)) 89 && sigExtra; 90 } 91 } else if ( 92 (0x7FFD < exp) 93 || ((exp == 0x7FFD) && doIncrement 94 && (softfloat_compare128M( 95 extSigPtr + indexMultiwordHi( 5, 4 ), maxSig ) 96 == 0)) 97 ) { 98 softfloat_raiseFlags( 99 softfloat_flag_overflow | softfloat_flag_inexact ); 100 if ( 101 roundNearEven 102 || (roundingMode == softfloat_round_near_maxMag) 103 || (roundingMode 104 == (sign ? softfloat_round_min : softfloat_round_max)) 105 ) { 106 ui = packToF128UI96( sign, 0x7FFF, 0 ); 107 uj = 0; 108 } else { 109 ui = packToF128UI96( sign, 0x7FFE, 0x0000FFFF ); 110 uj = 0xFFFFFFFF; 111 } 112 zWPtr[indexWordHi( 4 )] = ui; 113 zWPtr[indexWord( 4, 2 )] = uj; 114 zWPtr[indexWord( 4, 1 )] = uj; 115 zWPtr[indexWord( 4, 0 )] = uj; 116 return; 117 } 118 } 119 if ( sigExtra ) softfloat_exceptionFlags |= softfloat_flag_inexact; 120 uj = extSigPtr[indexWord( 5, 1 )]; 121 if ( doIncrement ) { 122 ++uj; 123 if ( uj ) { 124 if ( ! (sigExtra & 0x7FFFFFFF) && roundNearEven ) uj &= ~1; 125 zWPtr[indexWord( 4, 2 )] = extSigPtr[indexWord( 5, 3 )]; 126 zWPtr[indexWord( 4, 1 )] = extSigPtr[indexWord( 5, 2 )]; 127 zWPtr[indexWord( 4, 0 )] = uj; 128 ui = extSigPtr[indexWordHi( 5 )]; 129 } else { 130 zWPtr[indexWord( 4, 0 )] = uj; 131 ui = extSigPtr[indexWord( 5, 2 )] + 1; 132 zWPtr[indexWord( 4, 1 )] = ui; 133 uj = extSigPtr[indexWord( 5, 3 )]; 134 if ( ui ) { 135 zWPtr[indexWord( 4, 2 )] = uj; 136 ui = extSigPtr[indexWordHi( 5 )]; 137 } else { 138 ++uj; 139 zWPtr[indexWord( 4, 2 )] = uj; 140 ui = extSigPtr[indexWordHi( 5 )]; 141 if ( ! uj ) ++ui; 142 } 143 } 144 } else { 145 zWPtr[indexWord( 4, 0 )] = uj; 146 ui = extSigPtr[indexWord( 5, 2 )]; 147 zWPtr[indexWord( 4, 1 )] = ui; 148 uj |= ui; 149 ui = extSigPtr[indexWord( 5, 3 )]; 150 zWPtr[indexWord( 4, 2 )] = ui; 151 uj |= ui; 152 ui = extSigPtr[indexWordHi( 5 )]; 153 uj |= ui; 154 if ( ! uj ) exp = 0; 155 } 156 zWPtr[indexWordHi( 4 )] = packToF128UI96( sign, exp, ui ); 157 158 } 159 160