diff options
Diffstat (limited to 'source/s_subMagsF64.c')
| -rw-r--r-- | source/s_subMagsF64.c | 120 |
1 files changed, 73 insertions, 47 deletions
diff --git a/source/s_subMagsF64.c b/source/s_subMagsF64.c index e499d98..9c44368 100644 --- a/source/s_subMagsF64.c +++ b/source/s_subMagsF64.c @@ -2,10 +2,10 @@ /*============================================================================ This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic -Package, Release 3a, by John R. Hauser. +Package, Release 3b, by John R. Hauser. -Copyright 2011, 2012, 2013, 2014 The Regents of the University of California. -All rights reserved. +Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of +California. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: @@ -50,61 +50,87 @@ float64_t uint_fast64_t sigB; int_fast16_t expDiff; uint_fast64_t uiZ; + int_fast64_t sigDiff; + int_fast8_t shiftDist; int_fast16_t expZ; uint_fast64_t sigZ; union ui64_f64 uZ; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ expA = expF64UI( uiA ); sigA = fracF64UI( uiA ); expB = expF64UI( uiB ); sigB = fracF64UI( uiB ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ expDiff = expA - expB; - sigA <<= 10; - sigB <<= 10; - if ( 0 < expDiff ) goto expABigger; - if ( expDiff < 0 ) goto expBBigger; - if ( expA == 0x7FF ) { - if ( sigA | sigB ) goto propagateNaN; - softfloat_raiseFlags( softfloat_flag_invalid ); - uiZ = defaultNaNF64UI; + if ( ! expDiff ) { + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + if ( expA == 0x7FF ) { + if ( sigA | sigB ) goto propagateNaN; + softfloat_raiseFlags( softfloat_flag_invalid ); + uiZ = defaultNaNF64UI; + goto uiZ; + } + sigDiff = sigA - sigB; + if ( ! sigDiff ) { + uiZ = + packToF64UI( + (softfloat_roundingMode == softfloat_round_min), 0, 0 ); + goto uiZ; + } + if ( expA ) --expA; + if ( sigDiff < 0 ) { + signZ = ! signZ; + sigDiff = -sigDiff; + } + shiftDist = softfloat_countLeadingZeros64( sigDiff ) - 11; + expZ = expA - shiftDist; + if ( expZ < 0 ) { + shiftDist = expA; + expZ = 0; + } + uiZ = packToF64UI( signZ, expZ, sigDiff<<shiftDist ); goto uiZ; + } else { + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + sigA <<= 10; + sigB <<= 10; + if ( expDiff < 0 ) { + /*---------------------------------------------------------------- + *----------------------------------------------------------------*/ + signZ = ! signZ; + if ( expB == 0x7FF ) { + if ( sigB ) goto propagateNaN; + uiZ = packToF64UI( signZ, 0x7FF, 0 ); + goto uiZ; + } + sigA += expA ? UINT64_C( 0x4000000000000000 ) : sigA; + sigA = softfloat_shiftRightJam64( sigA, -expDiff ); + sigB |= UINT64_C( 0x4000000000000000 ); + expZ = expB; + sigZ = sigB - sigA; + } else { + /*---------------------------------------------------------------- + *----------------------------------------------------------------*/ + if ( expA == 0x7FF ) { + if ( sigA ) goto propagateNaN; + uiZ = uiA; + goto uiZ; + } + sigB += expB ? UINT64_C( 0x4000000000000000 ) : sigB; + sigB = softfloat_shiftRightJam64( sigB, expDiff ); + sigA |= UINT64_C( 0x4000000000000000 ); + expZ = expA; + sigZ = sigA - sigB; + } + return softfloat_normRoundPackToF64( signZ, expZ - 1, sigZ ); } - if ( ! expA ) { - expA = 1; - expB = 1; - } - if ( sigB < sigA ) goto aBigger; - if ( sigA < sigB ) goto bBigger; - uiZ = packToF64UI( softfloat_roundingMode == softfloat_round_min, 0, 0 ); - goto uiZ; - expBBigger: - if ( expB == 0x7FF ) { - if ( sigB ) goto propagateNaN; - uiZ = packToF64UI( signZ ^ 1, 0x7FF, 0 ); - goto uiZ; - } - sigA += expA ? UINT64_C( 0x4000000000000000 ) : sigA; - sigA = softfloat_shiftRightJam64( sigA, -expDiff ); - sigB |= UINT64_C( 0x4000000000000000 ); - bBigger: - signZ ^= 1; - expZ = expB; - sigZ = sigB - sigA; - goto normRoundPack; - expABigger: - if ( expA == 0x7FF ) { - if ( sigA ) goto propagateNaN; - uiZ = uiA; - goto uiZ; - } - sigB += expB ? UINT64_C( 0x4000000000000000 ) : sigB; - sigB = softfloat_shiftRightJam64( sigB, expDiff ); - sigA |= UINT64_C( 0x4000000000000000 ); - aBigger: - expZ = expA; - sigZ = sigA - sigB; - normRoundPack: - return softfloat_normRoundPackToF64( signZ, expZ - 1, sigZ ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ propagateNaN: uiZ = softfloat_propagateNaNF64UI( uiA, uiB ); uiZ: |