diff options
Diffstat (limited to 'source/s_roundPackToF128.c')
-rw-r--r-- | source/s_roundPackToF128.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/source/s_roundPackToF128.c b/source/s_roundPackToF128.c new file mode 100644 index 0000000..f30a51a --- /dev/null +++ b/source/s_roundPackToF128.c @@ -0,0 +1,146 @@ + +/*============================================================================ + +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 "softfloat.h" + +float128_t + softfloat_roundPackToF128( + bool sign, + int_fast32_t exp, + uint_fast64_t sig64, + uint_fast64_t sig0, + uint_fast64_t sigExtra + ) +{ + uint_fast8_t roundingMode; + bool roundNearEven, doIncrement, isTiny; + struct uint128_extra sig128Extra; + uint_fast64_t uiZ64, uiZ0; + struct uint128 sig128; + union ui128_f128 uZ; + + roundingMode = softfloat_roundingMode; + roundNearEven = (roundingMode == softfloat_round_near_even); + doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); + if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { + doIncrement = + (roundingMode + == (sign ? softfloat_round_min : softfloat_round_max)) + && sigExtra; + } + if ( 0x7FFD <= (uint32_t) exp ) { + if ( exp < 0 ) { + isTiny = + (softfloat_detectTininess + == softfloat_tininess_beforeRounding) + || (exp < -1) + || ! doIncrement + || softfloat_lt128( + sig64, + sig0, + UINT64_C( 0x0001FFFFFFFFFFFF ), + UINT64_C( 0xFFFFFFFFFFFFFFFF ) + ); + sig128Extra = + softfloat_shiftRightJam128Extra( sig64, sig0, sigExtra, -exp ); + sig64 = sig128Extra.v.v64; + sig0 = sig128Extra.v.v0; + sigExtra = sig128Extra.extra; + exp = 0; + if ( isTiny && sigExtra ) { + softfloat_raiseFlags( softfloat_flag_underflow ); + } + doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); + if ( + ! roundNearEven + && (roundingMode != softfloat_round_near_maxMag) + ) { + doIncrement = + (roundingMode + == (sign ? softfloat_round_min : softfloat_round_max)) + && sigExtra; + } + } else if ( + (0x7FFD < exp) + || ((exp == 0x7FFD) + && softfloat_eq128( + sig64, + sig0, + UINT64_C( 0x0001FFFFFFFFFFFF ), + UINT64_C( 0xFFFFFFFFFFFFFFFF ) + ) + && doIncrement) + ) { + softfloat_raiseFlags( + softfloat_flag_overflow | softfloat_flag_inexact ); + if ( + roundNearEven + || (roundingMode == softfloat_round_near_maxMag) + || (roundingMode + == (sign ? softfloat_round_min : softfloat_round_max)) + ) { + uiZ64 = packToF128UI64( sign, 0x7FFF, 0 ); + uiZ0 = 0; + } else { + uiZ64 = + packToF128UI64( + sign, 0x7FFE, UINT64_C( 0x0000FFFFFFFFFFFF ) ); + uiZ0 = UINT64_C( 0xFFFFFFFFFFFFFFFF ); + } + goto uiZ; + } + } + if ( sigExtra ) softfloat_exceptionFlags |= softfloat_flag_inexact; + if ( doIncrement ) { + sig128 = softfloat_add128( sig64, sig0, 0, 1 ); + sig64 = sig128.v64; + sig0 = + sig128.v0 + & ~(! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF )) + & roundNearEven); + } else { + if ( ! (sig64 | sig0) ) exp = 0; + } + uiZ64 = packToF128UI64( sign, exp, sig64 ); + uiZ0 = sig0; + uiZ: + uZ.ui.v64 = uiZ64; + uZ.ui.v0 = uiZ0; + return uZ.f; + +} + |