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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, 2016 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 |
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| 44 | float32_t f32_sqrt( float32_t a SOFTFLOAT_STATE_DECL_COMMA )
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| 45 | {
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| 46 | union ui32_f32 uA;
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| 47 | uint_fast32_t uiA;
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| 48 | bool signA;
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| 49 | int_fast16_t expA;
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| 50 | uint_fast32_t sigA, uiZ;
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| 51 | struct exp16_sig32 normExpSig;
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| 52 | int_fast16_t expZ;
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| 53 | uint_fast32_t sigZ, shiftedSigZ;
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| 54 | uint32_t negRem;
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| 55 | union ui32_f32 uZ;
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| 56 |
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| 57 | /*------------------------------------------------------------------------
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| 58 | *------------------------------------------------------------------------*/
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| 59 | uA.f = a;
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| 60 | uiA = uA.ui;
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| 61 | signA = signF32UI( uiA );
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| 62 | expA = expF32UI( uiA );
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| 63 | sigA = fracF32UI( uiA );
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| 64 | /*------------------------------------------------------------------------
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| 65 | *------------------------------------------------------------------------*/
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| 66 | if ( expA == 0xFF ) {
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| 67 | if ( sigA ) {
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| 68 | uiZ = softfloat_propagateNaNF32UI( uiA, 0 SOFTFLOAT_STATE_ARG_COMMA );
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| 69 | goto uiZ;
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| 70 | }
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| 71 | if ( ! signA ) return a;
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| 72 | goto invalid;
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| 73 | }
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| 74 | /*------------------------------------------------------------------------
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| 75 | *------------------------------------------------------------------------*/
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| 76 | if ( signA ) {
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| 77 | if ( ! (expA | sigA) ) return a;
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| 78 | goto invalid;
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| 79 | }
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| 80 | /*------------------------------------------------------------------------
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| 81 | *------------------------------------------------------------------------*/
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| 82 | if ( ! expA ) {
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| 83 | if ( ! sigA ) return a;
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| 84 | normExpSig = softfloat_normSubnormalF32Sig( sigA );
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| 85 | expA = normExpSig.exp;
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| 86 | sigA = normExpSig.sig;
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| 87 | }
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| 88 | /*------------------------------------------------------------------------
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| 89 | *------------------------------------------------------------------------*/
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| 90 | expZ = ((expA - 0x7F)>>1) + 0x7E;
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| 91 | expA &= 1;
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| 92 | sigA = (sigA | 0x00800000)<<8;
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| 93 | sigZ =
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| 94 | ((uint_fast64_t) sigA * softfloat_approxRecipSqrt32_1( expA, sigA ))
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| 95 | >>32;
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| 96 | if ( expA ) sigZ >>= 1;
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| 97 | /*------------------------------------------------------------------------
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| 98 | *------------------------------------------------------------------------*/
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| 99 | sigZ += 2;
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| 100 | if ( (sigZ & 0x3F) < 2 ) {
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| 101 | shiftedSigZ = sigZ>>2;
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| 102 | negRem = shiftedSigZ * shiftedSigZ;
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| 103 | sigZ &= ~3;
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| 104 | if ( negRem & 0x80000000 ) {
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| 105 | sigZ |= 1;
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| 106 | } else {
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| 107 | if ( negRem ) --sigZ;
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| 108 | }
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| 109 | }
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| 110 | return softfloat_roundPackToF32( 0, expZ, sigZ SOFTFLOAT_STATE_ARG_COMMA );
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| 111 | /*------------------------------------------------------------------------
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| 112 | *------------------------------------------------------------------------*/
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| 113 | invalid:
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| 114 | softfloat_raiseFlags( softfloat_flag_invalid SOFTFLOAT_STATE_ARG_COMMA );
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| 115 | uiZ = defaultNaNF32UI;
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| 116 | uiZ:
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| 117 | uZ.ui = uiZ;
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| 118 | return uZ.f;
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| 119 |
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| 120 | }
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| 121 |
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