96 lines
3.8 KiB
C
96 lines
3.8 KiB
C
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/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3e, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
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California. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
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be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "platform.h"
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#include "internals.h"
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#include "specialize.h"
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#include "softfloat.h"
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float16_t f128_to_f16( float128_t a )
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{
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union ui128_f128 uA;
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uint_fast64_t uiA64, uiA0;
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bool sign;
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int_fast32_t exp;
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uint_fast64_t frac64;
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struct commonNaN commonNaN;
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uint_fast16_t uiZ, frac16;
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union ui16_f16 uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uA.f = a;
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uiA64 = uA.ui.v64;
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uiA0 = uA.ui.v0;
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sign = signF128UI64( uiA64 );
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exp = expF128UI64( uiA64 );
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frac64 = fracF128UI64( uiA64 ) | (uiA0 != 0);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( exp == 0x7FFF ) {
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if ( frac64 ) {
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softfloat_f128UIToCommonNaN( uiA64, uiA0, &commonNaN );
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uiZ = softfloat_commonNaNToF16UI( &commonNaN );
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} else {
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uiZ = packToF16UI( sign, 0x1F, 0 );
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}
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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frac16 = softfloat_shortShiftRightJam64( frac64, 34 );
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if ( ! (exp | frac16) ) {
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uiZ = packToF16UI( sign, 0, 0 );
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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exp -= 0x3FF1;
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if ( sizeof (int_fast16_t) < sizeof (int_fast32_t) ) {
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if ( exp < -0x40 ) exp = -0x40;
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}
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return softfloat_roundPackToF16( sign, exp, frac16 | 0x4000 );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uiZ:
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uZ.ui = uiZ;
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return uZ.f;
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}
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