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88 lines
3.1 KiB
C
88 lines
3.1 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 3, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014 The Regents of the University of California
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(Regents). All Rights Reserved. Redistribution and use in source and binary
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forms, with or without modification, are permitted provided that the following
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conditions are met:
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Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer.
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Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer in the
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documentation and/or other materials provided with the distribution. Neither
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the name of the Regents nor the names of its contributors may be used to
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endorse or promote products derived from this software without specific prior
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written permission.
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IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
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SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
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OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
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BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
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TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
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HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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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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float64_t f128_to_f64( 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 sig64, sig0;
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struct commonNaN commonNaN;
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uint_fast64_t uiZ;
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struct uint128 sig128;
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union ui64_f64 uZ;
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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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sig64 = fracF128UI64( uiA64 );
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sig0 = uiA0;
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if ( exp == 0x7FFF ) {
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if ( sig64 | sig0 ) {
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softfloat_f128UIToCommonNaN( uiA64, uiA0, &commonNaN );
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uiZ = softfloat_commonNaNToF64UI( &commonNaN );
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} else {
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uiZ = packToF64UI( sign, 0x7FF, 0 );
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}
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goto uiZ;
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}
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sig128 = softfloat_shortShiftLeft128( sig64, sig0, 14 );
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sig64 = sig128.v64 | (sig128.v0 != 0);
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if ( ! (exp | sig64) ) {
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uiZ = packToF64UI( sign, 0, 0 );
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goto uiZ;
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}
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exp -= 0x3C01;
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if ( sizeof (int_fast16_t) < sizeof (int_fast32_t) ) {
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if ( exp < -0x1000 ) exp = -0x1000;
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}
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return
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softfloat_roundPackToF64(
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sign, exp, sig64 | UINT64_C( 0x4000000000000000 ) );
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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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