1
2/*============================================================================
3
4This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
5Package, Release 3e, by John R. Hauser.
6
7Copyright 2011, 2012, 2013, 2014, 2017 The Regents of the University of
8California.  All rights reserved.
9
10Redistribution and use in source and binary forms, with or without
11modification, are permitted provided that the following conditions are met:
12
13 1. Redistributions of source code must retain the above copyright notice,
14    this list of conditions, and the following disclaimer.
15
16 2. Redistributions in binary form must reproduce the above copyright notice,
17    this list of conditions, and the following disclaimer in the documentation
18    and/or other materials provided with the distribution.
19
20 3. Neither the name of the University nor the names of its contributors may
21    be used to endorse or promote products derived from this software without
22    specific prior written permission.
23
24THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
25EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
27DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
28DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34
35=============================================================================*/
36
37#include <stdbool.h>
38#include <stdint.h>
39#include "platform.h"
40#include "internals.h"
41#include "specialize.h"
42#include "softfloat.h"
43
44#ifdef SOFTFLOAT_FAST_INT64
45
46void
47 extF80M_roundToInt(
48     const extFloat80_t *aPtr,
49     uint_fast8_t roundingMode,
50     bool exact,
51     extFloat80_t *zPtr
52 )
53{
54
55    *zPtr = extF80_roundToInt( *aPtr, roundingMode, exact );
56
57}
58
59#else
60
61void
62 extF80M_roundToInt(
63     const extFloat80_t *aPtr,
64     uint_fast8_t roundingMode,
65     bool exact,
66     extFloat80_t *zPtr
67 )
68{
69    const struct extFloat80M *aSPtr;
70    struct extFloat80M *zSPtr;
71    uint_fast16_t uiA64, signUI64;
72    int32_t exp;
73    uint64_t sigA;
74    uint_fast16_t uiZ64;
75    uint64_t sigZ, lastBitMask, roundBitsMask;
76
77    /*------------------------------------------------------------------------
78    *------------------------------------------------------------------------*/
79    aSPtr = (const struct extFloat80M *) aPtr;
80    zSPtr = (struct extFloat80M *) zPtr;
81    /*------------------------------------------------------------------------
82    *------------------------------------------------------------------------*/
83    uiA64 = aSPtr->signExp;
84    signUI64 = uiA64 & packToExtF80UI64( 1, 0 );
85    exp = expExtF80UI64( uiA64 );
86    sigA = aSPtr->signif;
87    /*------------------------------------------------------------------------
88    *------------------------------------------------------------------------*/
89    if ( !(sigA & UINT64_C( 0x8000000000000000 )) && (exp != 0x7FFF) ) {
90        if ( !sigA ) {
91            uiZ64 = signUI64;
92            sigZ = 0;
93            goto uiZ;
94        }
95        exp += softfloat_normExtF80SigM( &sigA );
96    }
97    /*------------------------------------------------------------------------
98    *------------------------------------------------------------------------*/
99    if ( exp <= 0x3FFE ) {
100        if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact );
101        switch ( roundingMode ) {
102         case softfloat_round_near_even:
103            if ( !(sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF )) ) break;
104         case softfloat_round_near_maxMag:
105            if ( exp == 0x3FFE ) goto mag1;
106            break;
107         case softfloat_round_min:
108            if ( signUI64 ) goto mag1;
109            break;
110         case softfloat_round_max:
111            if ( !signUI64 ) goto mag1;
112            break;
113#ifdef SOFTFLOAT_ROUND_ODD
114         case softfloat_round_odd:
115            goto mag1;
116#endif
117        }
118        uiZ64 = signUI64;
119        sigZ = 0;
120        goto uiZ;
121     mag1:
122        uiZ64 = signUI64 | 0x3FFF;
123        sigZ = UINT64_C( 0x8000000000000000 );
124        goto uiZ;
125    }
126    /*------------------------------------------------------------------------
127    *------------------------------------------------------------------------*/
128    if ( 0x403E <= exp ) {
129        if ( exp == 0x7FFF ) {
130            if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) {
131                softfloat_propagateNaNExtF80M( aSPtr, 0, zSPtr );
132                return;
133            }
134            sigZ = UINT64_C( 0x8000000000000000 );
135        } else {
136            sigZ = sigA;
137        }
138        uiZ64 = signUI64 | exp;
139        goto uiZ;
140    }
141    /*------------------------------------------------------------------------
142    *------------------------------------------------------------------------*/
143    uiZ64 = signUI64 | exp;
144    lastBitMask = (uint64_t) 1<<(0x403E - exp);
145    roundBitsMask = lastBitMask - 1;
146    sigZ = sigA;
147    if ( roundingMode == softfloat_round_near_maxMag ) {
148        sigZ += lastBitMask>>1;
149    } else if ( roundingMode == softfloat_round_near_even ) {
150        sigZ += lastBitMask>>1;
151        if ( !(sigZ & roundBitsMask) ) sigZ &= ~lastBitMask;
152    } else if (
153        roundingMode == (signUI64 ? softfloat_round_min : softfloat_round_max)
154    ) {
155        sigZ += roundBitsMask;
156    }
157    sigZ &= ~roundBitsMask;
158    if ( !sigZ ) {
159        ++uiZ64;
160        sigZ = UINT64_C( 0x8000000000000000 );
161    }
162    if ( sigZ != sigA ) {
163#ifdef SOFTFLOAT_ROUND_ODD
164        if ( roundingMode == softfloat_round_odd ) sigZ |= lastBitMask;
165#endif
166        if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact );
167    }
168 uiZ:
169    zSPtr->signExp = uiZ64;
170    zSPtr->signif = sigZ;
171    return;
172
173}
174
175#endif
176
177