mirror of
https://github.com/86Box/86Box.git
synced 2026-02-22 09:35:32 -07:00
143 lines
6.2 KiB
C++
143 lines
6.2 KiB
C++
/*============================================================================
|
|
|
|
This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
|
|
Package, Release 3e, by John R. Hauser.
|
|
|
|
Copyright 2011, 2012, 2013, 2014, 2017 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:
|
|
|
|
1. Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions, and the following disclaimer.
|
|
|
|
2. Redistributions in binary form must reproduce the above copyright notice,
|
|
this list of conditions, and the following disclaimer in the documentation
|
|
and/or other materials provided with the distribution.
|
|
|
|
3. Neither the name of the University nor the names of its contributors may
|
|
be used to endorse or promote products derived from this software without
|
|
specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
|
|
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
|
|
DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
|
|
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
|
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
|
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
=============================================================================*/
|
|
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
#include "internals.h"
|
|
#include "primitives.h"
|
|
#include "specialize.h"
|
|
#include "softfloat.h"
|
|
|
|
float128_t
|
|
f128_roundToInt(float128_t a, uint8_t roundingMode, bool exact, struct softfloat_status_t *status)
|
|
{
|
|
uint64_t uiA64, uiA0;
|
|
int32_t exp;
|
|
struct uint128 uiZ;
|
|
uint64_t lastBitMask0, roundBitsMask;
|
|
bool roundNearEven;
|
|
uint64_t lastBitMask64;
|
|
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
uiA64 = a.v64;
|
|
uiA0 = a.v0;
|
|
exp = expF128UI64(uiA64);
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if (0x402F <= exp) {
|
|
/*--------------------------------------------------------------------
|
|
*--------------------------------------------------------------------*/
|
|
if (0x406F <= exp) {
|
|
if ((exp == 0x7FFF) && (fracF128UI64(uiA64) | uiA0)) {
|
|
uiZ = softfloat_propagateNaNF128UI(uiA64, uiA0, 0, 0, status);
|
|
return uiZ;
|
|
}
|
|
return a;
|
|
}
|
|
/*--------------------------------------------------------------------
|
|
*--------------------------------------------------------------------*/
|
|
lastBitMask0 = (uint64_t) 2<<(0x406E - exp);
|
|
roundBitsMask = lastBitMask0 - 1;
|
|
uiZ.v64 = uiA64;
|
|
uiZ.v0 = uiA0;
|
|
roundNearEven = (roundingMode == softfloat_round_near_even);
|
|
if (roundNearEven || (roundingMode == softfloat_round_near_maxMag)) {
|
|
if (exp == 0x402F) {
|
|
if (UINT64_C(0x8000000000000000) <= uiZ.v0) {
|
|
++uiZ.v64;
|
|
if (roundNearEven && (uiZ.v0 == UINT64_C(0x8000000000000000))) {
|
|
uiZ.v64 &= ~1;
|
|
}
|
|
}
|
|
} else {
|
|
uiZ = softfloat_add128(uiZ.v64, uiZ.v0, 0, lastBitMask0>>1);
|
|
if (roundNearEven && !(uiZ.v0 & roundBitsMask)) {
|
|
uiZ.v0 &= ~lastBitMask0;
|
|
}
|
|
}
|
|
} else if (roundingMode == (signF128UI64(uiZ.v64) ? softfloat_round_min : softfloat_round_max)) {
|
|
uiZ = softfloat_add128(uiZ.v64, uiZ.v0, 0, roundBitsMask);
|
|
}
|
|
uiZ.v0 &= ~roundBitsMask;
|
|
lastBitMask64 = !lastBitMask0;
|
|
} else {
|
|
/*--------------------------------------------------------------------
|
|
*--------------------------------------------------------------------*/
|
|
if (exp < 0x3FFF) {
|
|
if (!((uiA64 & UINT64_C(0x7FFFFFFFFFFFFFFF)) | uiA0)) return a;
|
|
if (exact) softfloat_raiseFlags(status, softfloat_flag_inexact);
|
|
uiZ.v64 = uiA64 & packToF128UI64(1, 0, 0);
|
|
uiZ.v0 = 0;
|
|
switch (roundingMode) {
|
|
case softfloat_round_near_even:
|
|
if (!(fracF128UI64(uiA64) | uiA0)) break;
|
|
case softfloat_round_near_maxMag:
|
|
if (exp == 0x3FFE) uiZ.v64 |= packToF128UI64(0, 0x3FFF, 0);
|
|
break;
|
|
case softfloat_round_min:
|
|
if (uiZ.v64) uiZ.v64 = packToF128UI64(1, 0x3FFF, 0);
|
|
break;
|
|
case softfloat_round_max:
|
|
if (!uiZ.v64) uiZ.v64 = packToF128UI64(0, 0x3FFF, 0);
|
|
break;
|
|
}
|
|
return uiZ;
|
|
}
|
|
/*--------------------------------------------------------------------
|
|
*--------------------------------------------------------------------*/
|
|
uiZ.v64 = uiA64;
|
|
uiZ.v0 = 0;
|
|
lastBitMask64 = (uint64_t) 1<<(0x402F - exp);
|
|
roundBitsMask = lastBitMask64 - 1;
|
|
if (roundingMode == softfloat_round_near_maxMag) {
|
|
uiZ.v64 += lastBitMask64>>1;
|
|
} else if (roundingMode == softfloat_round_near_even) {
|
|
uiZ.v64 += lastBitMask64>>1;
|
|
if (!((uiZ.v64 & roundBitsMask) | uiA0)) {
|
|
uiZ.v64 &= ~lastBitMask64;
|
|
}
|
|
} else if (roundingMode == (signF128UI64(uiZ.v64) ? softfloat_round_min : softfloat_round_max)) {
|
|
uiZ.v64 = (uiZ.v64 | (uiA0 != 0)) + roundBitsMask;
|
|
}
|
|
uiZ.v64 &= ~roundBitsMask;
|
|
lastBitMask0 = 0;
|
|
}
|
|
if ((uiZ.v64 != uiA64) || (uiZ.v0 != uiA0)) {
|
|
if (exact) softfloat_raiseFlags(status, softfloat_flag_inexact);
|
|
}
|
|
return uiZ;
|
|
}
|