| |
| /*============================================================================ |
| |
| 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" |
| |
| float128_t |
| softfloat_subMagsF128( |
| uint_fast64_t uiA64, |
| uint_fast64_t uiA0, |
| uint_fast64_t uiB64, |
| uint_fast64_t uiB0, |
| bool signZ |
| ) |
| { |
| int_fast32_t expA; |
| struct uint128 sigA; |
| int_fast32_t expB; |
| struct uint128 sigB, sigZ; |
| int_fast32_t expDiff, expZ; |
| struct uint128 uiZ; |
| union ui128_f128 uZ; |
| |
| expA = expF128UI64( uiA64 ); |
| sigA.v64 = fracF128UI64( uiA64 ); |
| sigA.v0 = uiA0; |
| expB = expF128UI64( uiB64 ); |
| sigB.v64 = fracF128UI64( uiB64 ); |
| sigB.v0 = uiB0; |
| sigA = softfloat_shortShiftLeft128( sigA.v64, sigA.v0, 4 ); |
| sigB = softfloat_shortShiftLeft128( sigB.v64, sigB.v0, 4 ); |
| expDiff = expA - expB; |
| if ( 0 < expDiff ) goto expABigger; |
| if ( expDiff < 0 ) goto expBBigger; |
| if ( expA == 0x7FFF ) { |
| if ( sigA.v64 | sigA.v0 | sigB.v64 | sigB.v0 ) goto propagateNaN; |
| softfloat_raiseFlags( softfloat_flag_invalid ); |
| uiZ.v64 = defaultNaNF128UI64; |
| uiZ.v0 = defaultNaNF128UI0; |
| goto uiZ; |
| } |
| expZ = expA; |
| if ( ! expZ ) expZ = 1; |
| if ( sigB.v64 < sigA.v64 ) goto aBigger; |
| if ( sigA.v64 < sigB.v64 ) goto bBigger; |
| if ( sigB.v0 < sigA.v0 ) goto aBigger; |
| if ( sigA.v0 < sigB.v0 ) goto bBigger; |
| uiZ.v64 = |
| packToF128UI64( |
| (softfloat_roundingMode == softfloat_round_min), 0, 0 ); |
| uiZ.v0 = 0; |
| goto uiZ; |
| expBBigger: |
| if ( expB == 0x7FFF ) { |
| if ( sigB.v64 | sigB.v0 ) goto propagateNaN; |
| uiZ.v64 = packToF128UI64( signZ ^ 1, 0x7FFF, 0 ); |
| uiZ.v0 = 0; |
| goto uiZ; |
| } |
| if ( expA ) { |
| sigA.v64 |= UINT64_C( 0x0010000000000000 ); |
| } else { |
| ++expDiff; |
| if ( ! expDiff ) goto newlyAlignedBBigger; |
| } |
| sigA = softfloat_shiftRightJam128( sigA.v64, sigA.v0, -expDiff ); |
| newlyAlignedBBigger: |
| expZ = expB; |
| sigB.v64 |= UINT64_C( 0x0010000000000000 ); |
| bBigger: |
| signZ ^= 1; |
| sigZ = softfloat_sub128( sigB.v64, sigB.v0, sigA.v64, sigA.v0 ); |
| goto normRoundPack; |
| expABigger: |
| if ( expA == 0x7FFF ) { |
| if ( sigA.v64 | sigA.v0 ) goto propagateNaN; |
| uiZ.v64 = uiA64; |
| uiZ.v0 = uiA0; |
| goto uiZ; |
| } |
| if ( expB ) { |
| sigB.v64 |= UINT64_C( 0x0010000000000000 ); |
| } else { |
| --expDiff; |
| if ( ! expDiff ) goto newlyAlignedABigger; |
| } |
| sigB = softfloat_shiftRightJam128( sigB.v64, sigB.v0, expDiff ); |
| newlyAlignedABigger: |
| expZ = expA; |
| sigA.v64 |= UINT64_C( 0x0010000000000000 ); |
| aBigger: |
| sigZ = softfloat_sub128( sigA.v64, sigA.v0, sigB.v64, sigB.v0 ); |
| normRoundPack: |
| return softfloat_normRoundPackToF128( signZ, expZ - 5, sigZ.v64, sigZ.v0 ); |
| propagateNaN: |
| uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 ); |
| uiZ: |
| uZ.ui = uiZ; |
| return uZ.f; |
| |
| } |
| |