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 "specialize.h" 43 #include "softfloat.h" 44 45 float128_t f128_roundToInt(float128_t a,uint_fast8_t roundingMode,bool exact)46 f128_roundToInt( float128_t a, uint_fast8_t roundingMode, bool exact ) 47 { 48 union ui128_f128 uA; 49 uint_fast64_t uiA64, uiA0; 50 int_fast32_t exp; 51 struct uint128 uiZ; 52 uint_fast64_t lastBitMask, roundBitsMask; 53 bool roundNearEven; 54 union ui128_f128 uZ; 55 56 /*------------------------------------------------------------------------ 57 *------------------------------------------------------------------------*/ 58 uA.f = a; 59 uiA64 = uA.ui.v64; 60 uiA0 = uA.ui.v0; 61 exp = expF128UI64( uiA64 ); 62 /*------------------------------------------------------------------------ 63 *------------------------------------------------------------------------*/ 64 if ( 0x402F <= exp ) { 65 /*-------------------------------------------------------------------- 66 *--------------------------------------------------------------------*/ 67 if ( 0x406F <= exp ) { 68 if ( (exp == 0x7FFF) && (fracF128UI64( uiA64 ) | uiA0) ) { 69 uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, 0, 0 ); 70 goto uiZ; 71 } 72 return a; 73 } 74 /*-------------------------------------------------------------------- 75 *--------------------------------------------------------------------*/ 76 lastBitMask = (uint_fast64_t) 2<<(0x406E - exp); 77 roundBitsMask = lastBitMask - 1; 78 uiZ.v64 = uiA64; 79 uiZ.v0 = uiA0; 80 roundNearEven = (roundingMode == softfloat_round_near_even); 81 if ( roundNearEven || (roundingMode == softfloat_round_near_maxMag) ) { 82 if ( exp == 0x402F ) { 83 if ( UINT64_C( 0x8000000000000000 ) <= uiZ.v0 ) { 84 ++uiZ.v64; 85 if ( 86 roundNearEven 87 && (uiZ.v0 == UINT64_C( 0x8000000000000000 )) 88 ) { 89 uiZ.v64 &= ~1; 90 } 91 } 92 } else { 93 uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, lastBitMask>>1 ); 94 if ( roundNearEven && ! (uiZ.v0 & roundBitsMask) ) { 95 uiZ.v0 &= ~lastBitMask; 96 } 97 } 98 } else if ( roundingMode != softfloat_round_minMag ) { 99 if ( 100 signF128UI64( uiZ.v64 ) ^ (roundingMode == softfloat_round_max) 101 ) { 102 uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, roundBitsMask ); 103 } 104 } 105 uiZ.v0 &= ~roundBitsMask; 106 } else { 107 /*-------------------------------------------------------------------- 108 *--------------------------------------------------------------------*/ 109 if ( exp < 0x3FFF ) { 110 if ( ! ((uiA64 & UINT64_C( 0x7FFFFFFFFFFFFFFF )) | uiA0) ) { 111 return a; 112 } 113 if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact; 114 uiZ.v64 = uiA64 & packToF128UI64( 1, 0, 0 ); 115 uiZ.v0 = 0; 116 switch ( roundingMode ) { 117 case softfloat_round_near_even: 118 if ( ! (fracF128UI64( uiA64 ) | uiA0) ) break; 119 case softfloat_round_near_maxMag: 120 if ( exp == 0x3FFE ) uiZ.v64 |= packToF128UI64( 0, 0x3FFF, 0 ); 121 break; 122 case softfloat_round_min: 123 if ( uiZ.v64 ) uiZ.v64 = packToF128UI64( 1, 0x3FFF, 0 ); 124 break; 125 case softfloat_round_max: 126 if ( ! uiZ.v64 ) uiZ.v64 = packToF128UI64( 0, 0x3FFF, 0 ); 127 break; 128 } 129 goto uiZ; 130 } 131 /*-------------------------------------------------------------------- 132 *--------------------------------------------------------------------*/ 133 uiZ.v64 = uiA64; 134 uiZ.v0 = 0; 135 lastBitMask = (uint_fast64_t) 1<<(0x402F - exp); 136 roundBitsMask = lastBitMask - 1; 137 if ( roundingMode == softfloat_round_near_maxMag ) { 138 uiZ.v64 += lastBitMask>>1; 139 } else if ( roundingMode == softfloat_round_near_even ) { 140 uiZ.v64 += lastBitMask>>1; 141 if ( ! ((uiZ.v64 & roundBitsMask) | uiA0) ) { 142 uiZ.v64 &= ~lastBitMask; 143 } 144 } else if ( roundingMode != softfloat_round_minMag ) { 145 if ( 146 signF128UI64( uiZ.v64 ) ^ (roundingMode == softfloat_round_max) 147 ) { 148 uiZ.v64 = (uiZ.v64 | (uiA0 != 0)) + roundBitsMask; 149 } 150 } 151 uiZ.v64 &= ~roundBitsMask; 152 } 153 if ( exact && ((uiZ.v64 != uiA64) || (uiZ.v0 != uiA0)) ) { 154 softfloat_exceptionFlags |= softfloat_flag_inexact; 155 } 156 uiZ: 157 uZ.ui = uiZ; 158 return uZ.f; 159 160 } 161 162