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91 lines
3.6 KiB
C
91 lines
3.6 KiB
C
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/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
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California (Regents). All Rights Reserved. Redistribution and use in source
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and binary forms, with or without modification, are permitted provided that
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the following conditions are met:
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Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer.
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Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer in the
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documentation and/or other materials provided with the distribution. Neither
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the name of the Regents nor the names of its contributors may be used to
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endorse or promote products derived from this software without specific prior
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written permission.
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IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
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SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
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OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
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BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
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TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
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HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "platform.h"
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#include "internals.h"
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#include "softfloat.h"
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float32_t
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softfloat_roundPackToF32( bool sign, int_fast16_t exp, uint_fast32_t sig )
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{
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uint_fast8_t roundingMode;
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bool roundNearEven;
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uint_fast8_t roundIncrement, roundBits;
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bool isTiny;
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uint_fast32_t uiZ;
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union ui32_f32 uZ;
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roundingMode = softfloat_roundingMode;
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roundNearEven = (roundingMode == softfloat_round_near_even);
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roundIncrement = 0x40;
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if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
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roundIncrement =
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(roundingMode
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== (sign ? softfloat_round_min : softfloat_round_max))
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? 0x7F
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: 0;
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}
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roundBits = sig & 0x7F;
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if ( 0xFD <= (uint16_t) exp ) {
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if ( exp < 0 ) {
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isTiny =
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(softfloat_detectTininess
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== softfloat_tininess_beforeRounding)
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|| (exp < -1)
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|| (sig + roundIncrement < 0x80000000);
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sig = softfloat_shiftRightJam32( sig, -exp );
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exp = 0;
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roundBits = sig & 0x7F;
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if ( isTiny && roundBits ) {
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softfloat_raiseFlags( softfloat_flag_underflow );
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}
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} else if ( (0xFD < exp) || (0x80000000 <= sig + roundIncrement) ) {
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softfloat_raiseFlags(
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softfloat_flag_overflow | softfloat_flag_inexact );
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uiZ = packToF32UI( sign, 0xFF, 0 ) - ! roundIncrement;
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goto uiZ;
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}
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}
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if ( roundBits ) softfloat_exceptionFlags |= softfloat_flag_inexact;
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sig = (sig + roundIncrement)>>7;
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sig &= ~(uint_fast32_t) (! (roundBits ^ 0x40) & roundNearEven);
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uiZ = packToF32UI( sign, sig ? exp : 0, sig );
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uiZ:
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uZ.ui = uiZ;
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return uZ.f;
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}
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