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https://github.com/ilyakooo0/urbit.git
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156 lines
5.7 KiB
C
156 lines
5.7 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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extFloat80_t
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softfloat_subMagsExtF80(
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uint_fast16_t uiA64,
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uint_fast64_t uiA0,
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uint_fast16_t uiB64,
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uint_fast64_t uiB0,
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bool signZ
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)
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{
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int_fast32_t expA;
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uint_fast64_t sigA;
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int_fast32_t expB;
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uint_fast64_t sigB;
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int_fast32_t expDiff;
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uint_fast16_t uiZ64;
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uint_fast64_t uiZ0;
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int_fast32_t expZ;
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uint_fast64_t sigExtra;
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struct uint128 sig128, uiZ;
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union { struct extFloat80M s; extFloat80_t f; } uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expA = expExtF80UI64( uiA64 );
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sigA = uiA0;
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expB = expExtF80UI64( uiB64 );
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sigB = uiB0;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expDiff = expA - expB;
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if ( 0 < expDiff ) goto expABigger;
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if ( expDiff < 0 ) goto expBBigger;
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if ( expA == 0x7FFF ) {
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if ( (sigA | sigB) & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) {
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goto propagateNaN;
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}
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softfloat_raiseFlags( softfloat_flag_invalid );
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uiZ64 = defaultNaNExtF80UI64;
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uiZ0 = defaultNaNExtF80UI0;
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expZ = expA;
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if ( ! expZ ) expZ = 1;
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sigExtra = 0;
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if ( sigB < sigA ) goto aBigger;
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if ( sigA < sigB ) goto bBigger;
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uiZ64 =
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packToExtF80UI64( (softfloat_roundingMode == softfloat_round_min), 0 );
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uiZ0 = 0;
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goto uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expBBigger:
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if ( expB == 0x7FFF ) {
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if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
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uiZ64 = packToExtF80UI64( signZ ^ 1, 0x7FFF );
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uiZ0 = UINT64_C( 0x8000000000000000 );
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goto uiZ;
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}
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if ( ! expA ) {
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++expDiff;
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sigExtra = 0;
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if ( ! expDiff ) goto newlyAlignedBBigger;
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}
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sig128 = softfloat_shiftRightJam128( sigA, 0, -expDiff );
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sigA = sig128.v64;
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sigExtra = sig128.v0;
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newlyAlignedBBigger:
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expZ = expB;
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bBigger:
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signZ ^= 1;
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sig128 = softfloat_sub128( sigB, 0, sigA, sigExtra );
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goto normRoundPack;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expABigger:
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if ( expA == 0x7FFF ) {
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if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
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uiZ64 = uiA64;
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uiZ0 = uiA0;
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goto uiZ;
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}
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if ( ! expB ) {
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--expDiff;
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sigExtra = 0;
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if ( ! expDiff ) goto newlyAlignedABigger;
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}
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sig128 = softfloat_shiftRightJam128( sigB, 0, expDiff );
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sigB = sig128.v64;
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sigExtra = sig128.v0;
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newlyAlignedABigger:
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expZ = expA;
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aBigger:
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sig128 = softfloat_sub128( sigA, 0, sigB, sigExtra );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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normRoundPack:
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return
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softfloat_normRoundPackToExtF80(
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signZ, expZ, sig128.v64, sig128.v0, extF80_roundingPrecision );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN:
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uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
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uiZ64 = uiZ.v64;
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uiZ0 = uiZ.v0;
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uiZ:
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uZ.s.signExp = uiZ64;
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uZ.s.signif = uiZ0;
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return uZ.f;
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}
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