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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 "softfloat.h"
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| 42 |
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| 43 | float16_t
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| 44 | softfloat_roundPackToF16( bool sign, int_fast16_t exp, uint_fast16_t sig SOFTFLOAT_STATE_DECL_COMMA )
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| 45 | {
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| 46 | uint_fast8_t roundingMode;
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| 47 | bool roundNearEven;
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| 48 | uint_fast8_t roundIncrement, roundBits;
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| 49 | bool isTiny;
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| 50 | uint_fast16_t uiZ;
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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 | roundingMode = softfloat_roundingMode;
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| 56 | roundNearEven = (roundingMode == softfloat_round_near_even);
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| 57 | roundIncrement = 0x8;
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| 58 | if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
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| 59 | roundIncrement =
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| 60 | (roundingMode
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| 61 | == (sign ? softfloat_round_min : softfloat_round_max))
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| 62 | ? 0xF
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| 63 | : 0;
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| 64 | }
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| 65 | roundBits = sig & 0xF;
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| 66 | /*------------------------------------------------------------------------
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| 67 | *------------------------------------------------------------------------*/
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| 68 | if ( 0x1D <= (unsigned int) exp ) {
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| 69 | if ( exp < 0 ) {
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| 70 | /*----------------------------------------------------------------
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| 71 | *----------------------------------------------------------------*/
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| 72 | isTiny =
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| 73 | (softfloat_detectTininess == softfloat_tininess_beforeRounding)
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| 74 | || (exp < -1) || (sig + roundIncrement < 0x8000);
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| 75 | sig = softfloat_shiftRightJam32( sig, -exp );
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| 76 | exp = 0;
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| 77 | roundBits = sig & 0xF;
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| 78 | if ( isTiny && roundBits ) {
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| 79 | softfloat_raiseFlags( softfloat_flag_underflow SOFTFLOAT_STATE_ARG_COMMA );
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| 80 | }
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| 81 | } else if ( (0x1D < exp) || (0x8000 <= sig + roundIncrement) ) {
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| 82 | /*----------------------------------------------------------------
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| 83 | *----------------------------------------------------------------*/
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| 84 | softfloat_raiseFlags(
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| 85 | softfloat_flag_overflow | softfloat_flag_inexact
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| 86 | SOFTFLOAT_STATE_ARG_COMMA );
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| 87 | uiZ = packToF16UI( sign, 0x1F, 0 ) - ! roundIncrement;
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| 88 | goto uiZ;
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| 89 | }
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| 90 | }
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| 91 | /*------------------------------------------------------------------------
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| 92 | *------------------------------------------------------------------------*/
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| 93 | sig = (sig + roundIncrement)>>4;
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| 94 | if ( roundBits ) {
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| 95 | softfloat_exceptionFlags |= softfloat_flag_inexact;
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| 96 | #ifdef SOFTFLOAT_ROUND_ODD
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| 97 | if ( roundingMode == softfloat_round_odd ) {
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| 98 | sig |= 1;
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| 99 | goto packReturn;
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| 100 | }
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| 101 | #endif
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| 102 | }
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| 103 | sig &= ~(uint_fast16_t) (! (roundBits ^ 8) & roundNearEven);
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| 104 | if ( ! sig ) exp = 0;
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| 105 | /*------------------------------------------------------------------------
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| 106 | *------------------------------------------------------------------------*/
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| 107 | packReturn:
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| 108 | uiZ = packToF16UI( sign, exp, sig );
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| 109 | uiZ:
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| 110 | uZ.ui = uiZ;
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| 111 | return uZ.f;
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| 112 |
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| 113 | }
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| 114 |
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