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 "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 roundingMode = softfloat_roundingMode; 60 roundNearEven = (roundingMode == softfloat_round_near_even); 61 doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); 62 if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { 63 doIncrement = 64 (roundingMode 65 == (sign ? softfloat_round_min : softfloat_round_max)) 66 && sigExtra; 67 } 68 if ( 0x7FFD <= (uint32_t) exp ) { 69 if ( exp < 0 ) { 70 isTiny = 71 (softfloat_detectTininess 72 == softfloat_tininess_beforeRounding) 73 || (exp < -1) 74 || ! doIncrement 75 || softfloat_lt128( 76 sig64, 77 sig0, 78 UINT64_C( 0x0001FFFFFFFFFFFF ), 79 UINT64_C( 0xFFFFFFFFFFFFFFFF ) 80 ); 81 sig128Extra = 82 softfloat_shiftRightJam128Extra( sig64, sig0, sigExtra, -exp ); 83 sig64 = sig128Extra.v.v64; 84 sig0 = sig128Extra.v.v0; 85 sigExtra = sig128Extra.extra; 86 exp = 0; 87 if ( isTiny && sigExtra ) { 88 softfloat_raiseFlags( softfloat_flag_underflow ); 89 } 90 doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); 91 if ( 92 ! roundNearEven 93 && (roundingMode != softfloat_round_near_maxMag) 94 ) { 95 doIncrement = 96 (roundingMode 97 == (sign ? softfloat_round_min : softfloat_round_max)) 98 && sigExtra; 99 } 100 } else if ( 101 (0x7FFD < exp) 102 || ((exp == 0x7FFD) 103 && softfloat_eq128( 104 sig64, 105 sig0, 106 UINT64_C( 0x0001FFFFFFFFFFFF ), 107 UINT64_C( 0xFFFFFFFFFFFFFFFF ) 108 ) 109 && doIncrement) 110 ) { 111 softfloat_raiseFlags( 112 softfloat_flag_overflow | softfloat_flag_inexact ); 113 if ( 114 roundNearEven 115 || (roundingMode == softfloat_round_near_maxMag) 116 || (roundingMode 117 == (sign ? softfloat_round_min : softfloat_round_max)) 118 ) { 119 uiZ64 = packToF128UI64( sign, 0x7FFF, 0 ); 120 uiZ0 = 0; 121 } else { 122 uiZ64 = 123 packToF128UI64( 124 sign, 0x7FFE, UINT64_C( 0x0000FFFFFFFFFFFF ) ); 125 uiZ0 = UINT64_C( 0xFFFFFFFFFFFFFFFF ); 126 } 127 goto uiZ; 128 } 129 } 130 if ( sigExtra ) softfloat_exceptionFlags |= softfloat_flag_inexact; 131 if ( doIncrement ) { 132 sig128 = softfloat_add128( sig64, sig0, 0, 1 ); 133 sig64 = sig128.v64; 134 sig0 = 135 sig128.v0 136 & ~(uint64_t) 137 (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF )) 138 & roundNearEven); 139 } else { 140 if ( ! (sig64 | sig0) ) exp = 0; 141 } 142 uiZ64 = packToF128UI64( sign, exp, sig64 ); 143 uiZ0 = sig0; 144 uiZ: 145 uZ.ui.v64 = uiZ64; 146 uZ.ui.v0 = uiZ0; 147 return uZ.f; 148 149 } 150 151