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, 2015, 2017 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 "softfloat.h" 42 43 float128_t softfloat_roundPackToF128(bool sign,int_fast32_t exp,uint_fast64_t sig64,uint_fast64_t sig0,uint_fast64_t sigExtra)44 softfloat_roundPackToF128( 45 bool sign, 46 int_fast32_t exp, 47 uint_fast64_t sig64, 48 uint_fast64_t sig0, 49 uint_fast64_t sigExtra 50 ) 51 { 52 uint_fast8_t roundingMode; 53 bool roundNearEven, doIncrement, isTiny; 54 struct uint128_extra sig128Extra; 55 uint_fast64_t uiZ64, uiZ0; 56 struct uint128 sig128; 57 union ui128_f128 uZ; 58 59 /*------------------------------------------------------------------------ 60 *------------------------------------------------------------------------*/ 61 roundingMode = softfloat_roundingMode; 62 roundNearEven = (roundingMode == softfloat_round_near_even); 63 doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); 64 if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { 65 doIncrement = 66 (roundingMode 67 == (sign ? softfloat_round_min : softfloat_round_max)) 68 && sigExtra; 69 } 70 /*------------------------------------------------------------------------ 71 *------------------------------------------------------------------------*/ 72 if ( 0x7FFD <= (uint32_t) exp ) { 73 if ( exp < 0 ) { 74 /*---------------------------------------------------------------- 75 *----------------------------------------------------------------*/ 76 isTiny = 77 (softfloat_detectTininess 78 == softfloat_tininess_beforeRounding) 79 || (exp < -1) 80 || ! doIncrement 81 || softfloat_lt128( 82 sig64, 83 sig0, 84 UINT64_C( 0x0001FFFFFFFFFFFF ), 85 UINT64_C( 0xFFFFFFFFFFFFFFFF ) 86 ); 87 sig128Extra = 88 softfloat_shiftRightJam128Extra( sig64, sig0, sigExtra, -exp ); 89 sig64 = sig128Extra.v.v64; 90 sig0 = sig128Extra.v.v0; 91 sigExtra = sig128Extra.extra; 92 exp = 0; 93 if ( isTiny && sigExtra ) { 94 softfloat_raiseFlags( softfloat_flag_underflow ); 95 } 96 doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); 97 if ( 98 ! roundNearEven 99 && (roundingMode != softfloat_round_near_maxMag) 100 ) { 101 doIncrement = 102 (roundingMode 103 == (sign ? softfloat_round_min : softfloat_round_max)) 104 && sigExtra; 105 } 106 } else if ( 107 (0x7FFD < exp) 108 || ((exp == 0x7FFD) 109 && softfloat_eq128( 110 sig64, 111 sig0, 112 UINT64_C( 0x0001FFFFFFFFFFFF ), 113 UINT64_C( 0xFFFFFFFFFFFFFFFF ) 114 ) 115 && doIncrement) 116 ) { 117 /*---------------------------------------------------------------- 118 *----------------------------------------------------------------*/ 119 softfloat_raiseFlags( 120 softfloat_flag_overflow | softfloat_flag_inexact ); 121 if ( 122 roundNearEven 123 || (roundingMode == softfloat_round_near_maxMag) 124 || (roundingMode 125 == (sign ? softfloat_round_min : softfloat_round_max)) 126 ) { 127 uiZ64 = packToF128UI64( sign, 0x7FFF, 0 ); 128 uiZ0 = 0; 129 } else { 130 uiZ64 = 131 packToF128UI64( 132 sign, 0x7FFE, UINT64_C( 0x0000FFFFFFFFFFFF ) ); 133 uiZ0 = UINT64_C( 0xFFFFFFFFFFFFFFFF ); 134 } 135 goto uiZ; 136 } 137 } 138 /*------------------------------------------------------------------------ 139 *------------------------------------------------------------------------*/ 140 if ( sigExtra ) { 141 softfloat_exceptionFlags |= softfloat_flag_inexact; 142 #ifdef SOFTFLOAT_ROUND_ODD 143 if ( roundingMode == softfloat_round_odd ) { 144 sig0 |= 1; 145 goto packReturn; 146 } 147 #endif 148 } 149 if ( doIncrement ) { 150 sig128 = softfloat_add128( sig64, sig0, 0, 1 ); 151 sig64 = sig128.v64; 152 sig0 = 153 sig128.v0 154 & ~(uint64_t) 155 (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF )) 156 & roundNearEven); 157 } else { 158 if ( ! (sig64 | sig0) ) exp = 0; 159 } 160 /*------------------------------------------------------------------------ 161 *------------------------------------------------------------------------*/ 162 packReturn: 163 uiZ64 = packToF128UI64( sign, exp, sig64 ); 164 uiZ0 = sig0; 165 uiZ: 166 uZ.ui.v64 = uiZ64; 167 uZ.ui.v0 = uiZ0; 168 return uZ.f; 169 170 } 171 172