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Diffstat (limited to 'source/s_roundPackToF32.c')
-rw-r--r-- | source/s_roundPackToF32.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/source/s_roundPackToF32.c b/source/s_roundPackToF32.c new file mode 100644 index 0000000..fbc3e44 --- /dev/null +++ b/source/s_roundPackToF32.c @@ -0,0 +1,90 @@ + +/*============================================================================ + +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" + +float32_t + softfloat_roundPackToF32( bool sign, int_fast16_t exp, uint_fast32_t sig ) +{ + uint_fast8_t roundingMode; + bool roundNearEven; + uint_fast8_t roundIncrement, roundBits; + bool isTiny; + uint_fast32_t uiZ; + union ui32_f32 uZ; + + roundingMode = softfloat_roundingMode; + roundNearEven = (roundingMode == softfloat_round_near_even); + roundIncrement = 0x40; + if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { + roundIncrement = + (roundingMode + == (sign ? softfloat_round_min : softfloat_round_max)) + ? 0x7F + : 0; + } + roundBits = sig & 0x7F; + if ( 0xFD <= (uint16_t) exp ) { + if ( exp < 0 ) { + isTiny = + (softfloat_detectTininess + == softfloat_tininess_beforeRounding) + || (exp < -1) + || (sig + roundIncrement < 0x80000000); + sig = softfloat_shiftRightJam32( sig, -exp ); + exp = 0; + roundBits = sig & 0x7F; + if ( isTiny && roundBits ) { + softfloat_raiseFlags( softfloat_flag_underflow ); + } + } else if ( (0xFD < exp) || (0x80000000 <= sig + roundIncrement) ) { + softfloat_raiseFlags( + softfloat_flag_overflow | softfloat_flag_inexact ); + uiZ = packToF32UI( sign, 0xFF, 0 ) - ! roundIncrement; + goto uiZ; + } + } + if ( roundBits ) softfloat_exceptionFlags |= softfloat_flag_inexact; + sig = (sig + roundIncrement)>>7; + sig &= ~(! (roundBits ^ 0x40) & roundNearEven); + uiZ = packToF32UI( sign, sig ? exp : 0, sig ); + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + |