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| 2 | /*============================================================================
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| 3 |
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| 4 | This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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| 5 | Package, Release 3e, by John R. Hauser.
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| 6 |
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| 7 | Copyright 2011, 2012, 2013, 2014, 2015, 2017 The Regents of the University of
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| 8 | California. All rights reserved.
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| 9 |
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| 10 | Redistribution and use in source and binary forms, with or without
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| 11 | modification, are permitted provided that the following conditions are met:
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| 12 |
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| 13 | 1. Redistributions of source code must retain the above copyright notice,
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| 14 | this list of conditions, and the following disclaimer.
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| 15 |
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| 16 | 2. Redistributions in binary form must reproduce the above copyright notice,
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| 17 | this list of conditions, and the following disclaimer in the documentation
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| 18 | and/or other materials provided with the distribution.
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| 19 |
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| 20 | 3. Neither the name of the University nor the names of its contributors may
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| 21 | be used to endorse or promote products derived from this software without
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| 22 | specific prior written permission.
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| 23 |
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| 24 | THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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| 25 | EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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| 26 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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| 27 | DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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| 28 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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| 29 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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| 30 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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| 31 | ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 32 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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| 33 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 34 |
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| 35 | =============================================================================*/
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| 36 |
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| 37 | #include <stdbool.h>
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| 38 | #include <stdint.h>
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| 39 | #include "platform.h"
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| 40 | #include "internals.h"
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| 41 | #include "specialize.h"
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| 42 | #include "softfloat.h"
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| 43 | #include <iprt/cdefs.h> /* VBox: for RT_FALL_THROUGH */
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| 44 |
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| 45 | float16_t f16_roundToInt( float16_t a, uint_fast8_t roundingMode, bool exact )
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| 46 | {
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| 47 | union ui16_f16 uA;
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| 48 | uint_fast16_t uiA;
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| 49 | int_fast8_t exp;
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| 50 | uint_fast16_t uiZ, lastBitMask, roundBitsMask;
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| 51 | union ui16_f16 uZ;
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| 52 |
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| 53 | /*------------------------------------------------------------------------
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| 54 | *------------------------------------------------------------------------*/
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| 55 | uA.f = a;
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| 56 | uiA = uA.ui;
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| 57 | exp = expF16UI( uiA );
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| 58 | /*------------------------------------------------------------------------
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| 59 | *------------------------------------------------------------------------*/
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| 60 | if ( exp <= 0xE ) {
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| 61 | if ( !(uint16_t) (uiA<<1) ) return a;
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| 62 | if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
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| 63 | uiZ = uiA & packToF16UI( 1, 0, 0 );
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| 64 | switch ( roundingMode ) {
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| 65 | case softfloat_round_near_even:
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| 66 | if ( !fracF16UI( uiA ) ) break;
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| 67 | RT_FALL_THROUGH(); /* VBox */
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| 68 | case softfloat_round_near_maxMag:
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| 69 | if ( exp == 0xE ) uiZ |= packToF16UI( 0, 0xF, 0 );
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| 70 | break;
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| 71 | case softfloat_round_min:
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| 72 | if ( uiZ ) uiZ = packToF16UI( 1, 0xF, 0 );
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| 73 | break;
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| 74 | case softfloat_round_max:
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| 75 | if ( !uiZ ) uiZ = packToF16UI( 0, 0xF, 0 );
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| 76 | break;
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| 77 | #ifdef SOFTFLOAT_ROUND_ODD
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| 78 | case softfloat_round_odd:
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| 79 | uiZ |= packToF16UI( 0, 0xF, 0 );
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| 80 | break;
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| 81 | #endif
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| 82 | }
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| 83 | goto uiZ;
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| 84 | }
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| 85 | /*------------------------------------------------------------------------
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| 86 | *------------------------------------------------------------------------*/
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| 87 | if ( 0x19 <= exp ) {
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| 88 | if ( (exp == 0x1F) && fracF16UI( uiA ) ) {
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| 89 | uiZ = softfloat_propagateNaNF16UI( uiA, 0 );
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| 90 | goto uiZ;
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| 91 | }
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| 92 | return a;
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| 93 | }
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| 94 | /*------------------------------------------------------------------------
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| 95 | *------------------------------------------------------------------------*/
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| 96 | uiZ = uiA;
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| 97 | lastBitMask = (uint_fast16_t) 1<<(0x19 - exp);
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| 98 | roundBitsMask = lastBitMask - 1;
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| 99 | if ( roundingMode == softfloat_round_near_maxMag ) {
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| 100 | uiZ += lastBitMask>>1;
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| 101 | } else if ( roundingMode == softfloat_round_near_even ) {
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| 102 | uiZ += lastBitMask>>1;
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| 103 | if ( !(uiZ & roundBitsMask) ) uiZ &= ~lastBitMask;
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| 104 | } else if (
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| 105 | roundingMode
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| 106 | == (signF16UI( uiZ ) ? softfloat_round_min : softfloat_round_max)
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| 107 | ) {
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| 108 | uiZ += roundBitsMask;
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| 109 | }
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| 110 | uiZ &= ~roundBitsMask;
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| 111 | if ( uiZ != uiA ) {
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| 112 | #ifdef SOFTFLOAT_ROUND_ODD
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| 113 | if ( roundingMode == softfloat_round_odd ) uiZ |= lastBitMask;
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| 114 | #endif
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| 115 | if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
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| 116 | }
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| 117 | uiZ:
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| 118 | uZ.ui = uiZ;
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| 119 | return uZ.f;
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| 120 |
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| 121 | }
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| 122 |
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