1 2/*============================================================================ 3 4This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic 5Package, Release 3e, by John R. Hauser. 6 7Copyright 2011, 2012, 2013, 2014, 2015, 2017 The Regents of the University of 8California. All rights reserved. 9 10Redistribution and use in source and binary forms, with or without 11modification, 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 24THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY 25EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 26WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE 27DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY 28DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 29(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 31ON 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 33SOFTWARE, 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 "specialize.h" 42#include "softfloat.h" 43 44float16_t f16_roundToInt( float16_t a, uint_fast8_t roundingMode, bool exact ) 45{ 46 union ui16_f16 uA; 47 uint_fast16_t uiA; 48 int_fast8_t exp; 49 uint_fast16_t uiZ, lastBitMask, roundBitsMask; 50 union ui16_f16 uZ; 51 52 /*------------------------------------------------------------------------ 53 *------------------------------------------------------------------------*/ 54 uA.f = a; 55 uiA = uA.ui; 56 exp = expF16UI( uiA ); 57 /*------------------------------------------------------------------------ 58 *------------------------------------------------------------------------*/ 59 if ( exp <= 0xE ) { 60 if ( !(uint16_t) (uiA<<1) ) return a; 61 if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact ); 62 uiZ = uiA & packToF16UI( 1, 0, 0 ); 63 switch ( roundingMode ) { 64 case softfloat_round_near_even: 65 if ( !fracF16UI( uiA ) ) break; 66 case softfloat_round_near_maxMag: 67 if ( exp == 0xE ) uiZ |= packToF16UI( 0, 0xF, 0 ); 68 break; 69 case softfloat_round_min: 70 if ( uiZ ) uiZ = packToF16UI( 1, 0xF, 0 ); 71 break; 72 case softfloat_round_max: 73 if ( !uiZ ) uiZ = packToF16UI( 0, 0xF, 0 ); 74 break; 75#ifdef SOFTFLOAT_ROUND_ODD 76 case softfloat_round_odd: 77 uiZ |= packToF16UI( 0, 0xF, 0 ); 78 break; 79#endif 80 } 81 goto uiZ; 82 } 83 /*------------------------------------------------------------------------ 84 *------------------------------------------------------------------------*/ 85 if ( 0x19 <= exp ) { 86 if ( (exp == 0x1F) && fracF16UI( uiA ) ) { 87 uiZ = softfloat_propagateNaNF16UI( uiA, 0 ); 88 goto uiZ; 89 } 90 return a; 91 } 92 /*------------------------------------------------------------------------ 93 *------------------------------------------------------------------------*/ 94 uiZ = uiA; 95 lastBitMask = (uint_fast16_t) 1<<(0x19 - exp); 96 roundBitsMask = lastBitMask - 1; 97 if ( roundingMode == softfloat_round_near_maxMag ) { 98 uiZ += lastBitMask>>1; 99 } else if ( roundingMode == softfloat_round_near_even ) { 100 uiZ += lastBitMask>>1; 101 if ( !(uiZ & roundBitsMask) ) uiZ &= ~lastBitMask; 102 } else if ( 103 roundingMode 104 == (signF16UI( uiZ ) ? softfloat_round_min : softfloat_round_max) 105 ) { 106 uiZ += roundBitsMask; 107 } 108 uiZ &= ~roundBitsMask; 109 if ( uiZ != uiA ) { 110#ifdef SOFTFLOAT_ROUND_ODD 111 if ( roundingMode == softfloat_round_odd ) uiZ |= lastBitMask; 112#endif 113 if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact ); 114 } 115 uiZ: 116 uZ.ui = uiZ; 117 return uZ.f; 118 119} 120 121