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Diffstat (limited to 'source/s_subMagsExtF80.c')
| -rw-r--r-- | source/s_subMagsExtF80.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/source/s_subMagsExtF80.c b/source/s_subMagsExtF80.c new file mode 100644 index 0000000..b929ff3 --- /dev/null +++ b/source/s_subMagsExtF80.c @@ -0,0 +1,155 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014 The Regents of the University of California +(Regents). All Rights Reserved. Redistribution and use in source and binary +forms, with or without modification, are permitted provided that the following +conditions are met: + +Redistributions of source code must retain the above copyright notice, +this list of conditions, and the following two paragraphs of disclaimer. +Redistributions in binary form must reproduce the above copyright notice, +this list of conditions, and the following two paragraphs of disclaimer in the +documentation and/or other materials provided with the distribution. Neither +the name of the Regents nor the names of its contributors may be used to +endorse or promote products derived from this software without specific prior +written permission. + +IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, +SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING +OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS +BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED +TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED +HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE +MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + +=============================================================================*/ + +#include <stdbool.h> +#include <stdint.h> +#include "platform.h" +#include "internals.h" +#include "specialize.h" +#include "softfloat.h" + +extFloat80_t + softfloat_subMagsExtF80( + uint_fast16_t uiA64, + uint_fast64_t uiA0, + uint_fast16_t uiB64, + uint_fast64_t uiB0, + bool signZ + ) +{ + int_fast32_t expA; + uint_fast64_t sigA; + int_fast32_t expB; + uint_fast64_t sigB; + int_fast32_t expDiff; + uint_fast16_t uiZ64; + uint_fast64_t uiZ0; + int_fast32_t expZ; + uint_fast64_t sigExtra; + struct uint128 sig128, uiZ; + union { struct extFloat80M s; extFloat80_t f; } uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + expA = expExtF80UI64( uiA64 ); + sigA = uiA0; + expB = expExtF80UI64( uiB64 ); + sigB = uiB0; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + expDiff = expA - expB; + if ( 0 < expDiff ) goto expABigger; + if ( expDiff < 0 ) goto expBBigger; + if ( expA == 0x7FFF ) { + if ( (sigA | sigB) & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) { + goto propagateNaN; + } + softfloat_raiseFlags( softfloat_flag_invalid ); + uiZ64 = defaultNaNExtF80UI64; + uiZ0 = defaultNaNExtF80UI0; + goto uiZ; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + expZ = expA; + if ( ! expZ ) expZ = 1; + sigExtra = 0; + if ( sigB < sigA ) goto aBigger; + if ( sigA < sigB ) goto bBigger; + uiZ64 = + packToExtF80UI64( (softfloat_roundingMode == softfloat_round_min), 0 ); + uiZ0 = 0; + goto uiZ; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + expBBigger: + if ( expB == 0x7FFF ) { + if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN; + uiZ64 = packToExtF80UI64( signZ ^ 1, 0x7FFF ); + uiZ0 = UINT64_C( 0x8000000000000000 ); + goto uiZ; + } + if ( ! expA ) { + ++expDiff; + sigExtra = 0; + if ( ! expDiff ) goto newlyAlignedBBigger; + } + sig128 = softfloat_shiftRightJam128( sigA, 0, -expDiff ); + sigA = sig128.v64; + sigExtra = sig128.v0; + newlyAlignedBBigger: + expZ = expB; + bBigger: + signZ ^= 1; + sig128 = softfloat_sub128( sigB, 0, sigA, sigExtra ); + goto normRoundPack; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + expABigger: + if ( expA == 0x7FFF ) { + if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN; + uiZ64 = uiA64; + uiZ0 = uiA0; + goto uiZ; + } + if ( ! expB ) { + --expDiff; + sigExtra = 0; + if ( ! expDiff ) goto newlyAlignedABigger; + } + sig128 = softfloat_shiftRightJam128( sigB, 0, expDiff ); + sigB = sig128.v64; + sigExtra = sig128.v0; + newlyAlignedABigger: + expZ = expA; + aBigger: + sig128 = softfloat_sub128( sigA, 0, sigB, sigExtra ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + normRoundPack: + return + softfloat_normRoundPackToExtF80( + signZ, expZ, sig128.v64, sig128.v0, extF80_roundingPrecision ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + propagateNaN: + uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 ); + uiZ64 = uiZ.v64; + uiZ0 = uiZ.v0; + uiZ: + uZ.s.signExp = uiZ64; + uZ.s.signif = uiZ0; + return uZ.f; + +} + |