| |
| /*============================================================================ |
| |
| 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" |
| |
| float64_t |
| softfloat_roundPackToF64( bool sign, int_fast16_t exp, uint_fast64_t sig ) |
| { |
| uint_fast8_t roundingMode; |
| bool roundNearEven; |
| uint_fast16_t roundIncrement, roundBits; |
| bool isTiny; |
| uint_fast64_t uiZ; |
| union ui64_f64 uZ; |
| |
| roundingMode = softfloat_roundingMode; |
| roundNearEven = (roundingMode == softfloat_round_near_even); |
| roundIncrement = 0x200; |
| if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { |
| roundIncrement = |
| (roundingMode |
| == (sign ? softfloat_round_min : softfloat_round_max)) |
| ? 0x3FF |
| : 0; |
| } |
| roundBits = sig & 0x3FF; |
| if ( 0x7FD <= (uint16_t) exp ) { |
| if ( exp < 0 ) { |
| isTiny = |
| (softfloat_detectTininess |
| == softfloat_tininess_beforeRounding) |
| || (exp < -1) |
| || (sig + roundIncrement < UINT64_C( 0x8000000000000000 )); |
| sig = softfloat_shiftRightJam64( sig, -exp ); |
| exp = 0; |
| roundBits = sig & 0x3FF; |
| if ( isTiny && roundBits ) { |
| softfloat_raiseFlags( softfloat_flag_underflow ); |
| } |
| } else if ( |
| (0x7FD < exp) |
| || (UINT64_C( 0x8000000000000000 ) <= sig + roundIncrement) |
| ) { |
| softfloat_raiseFlags( |
| softfloat_flag_overflow | softfloat_flag_inexact ); |
| uiZ = packToF64UI( sign, 0x7FF, 0 ) - ! roundIncrement; |
| goto uiZ; |
| } |
| } |
| if ( roundBits ) softfloat_exceptionFlags |= softfloat_flag_inexact; |
| sig = (sig + roundIncrement)>>10; |
| sig &= ~(! (roundBits ^ 0x200) & roundNearEven); |
| uiZ = packToF64UI( sign, sig ? exp : 0, sig ); |
| uiZ: |
| uZ.ui = uiZ; |
| return uZ.f; |
| |
| } |
| |