1 
2 /*============================================================================
3 
4 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
5 Package, Release 3e, by John R. Hauser.
6 
7 Copyright 2011, 2012, 2013, 2014, 2017 The Regents of the University of
8 California.  All rights reserved.
9 
10 Redistribution and use in source and binary forms, with or without
11 modification, 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 
24 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
25 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
27 DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
28 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31 ON 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
33 SOFTWARE, 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 "softfloat.h"
42 
43 void
softfloat_roundPackMToF128M(bool sign,int32_t exp,uint32_t * extSigPtr,uint32_t * zWPtr)44  softfloat_roundPackMToF128M(
45      bool sign, int32_t exp, uint32_t *extSigPtr, uint32_t *zWPtr )
46 {
47     uint_fast8_t roundingMode;
48     bool roundNearEven;
49     uint32_t sigExtra;
50     bool doIncrement, isTiny;
51     static const uint32_t maxSig[4] =
52         INIT_UINTM4( 0x0001FFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF );
53     uint32_t ui, uj;
54 
55     /*------------------------------------------------------------------------
56     *------------------------------------------------------------------------*/
57     roundingMode = softfloat_roundingMode;
58     roundNearEven = (roundingMode == softfloat_round_near_even);
59     sigExtra = extSigPtr[indexWordLo( 5 )];
60     doIncrement = (0x80000000 <= sigExtra);
61     if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
62         doIncrement =
63             (roundingMode
64                  == (sign ? softfloat_round_min : softfloat_round_max))
65                 && sigExtra;
66     }
67     /*------------------------------------------------------------------------
68     *------------------------------------------------------------------------*/
69     if ( 0x7FFD <= (uint32_t) exp ) {
70         if ( exp < 0 ) {
71             /*----------------------------------------------------------------
72             *----------------------------------------------------------------*/
73             isTiny =
74                    (softfloat_detectTininess
75                         == softfloat_tininess_beforeRounding)
76                 || (exp < -1)
77                 || ! doIncrement
78                 || (softfloat_compare128M(
79                         extSigPtr + indexMultiwordHi( 5, 4 ), maxSig )
80                         < 0);
81             softfloat_shiftRightJam160M( extSigPtr, -exp, extSigPtr );
82             exp = 0;
83             sigExtra = extSigPtr[indexWordLo( 5 )];
84             if ( isTiny && sigExtra ) {
85                 softfloat_raiseFlags( softfloat_flag_underflow );
86             }
87             doIncrement = (0x80000000 <= sigExtra);
88             if (
89                    ! roundNearEven
90                 && (roundingMode != softfloat_round_near_maxMag)
91             ) {
92                 doIncrement =
93                     (roundingMode
94                          == (sign ? softfloat_round_min : softfloat_round_max))
95                         && sigExtra;
96             }
97         } else if (
98                (0x7FFD < exp)
99             || ((exp == 0x7FFD) && doIncrement
100                     && (softfloat_compare128M(
101                             extSigPtr + indexMultiwordHi( 5, 4 ), maxSig )
102                             == 0))
103         ) {
104             /*----------------------------------------------------------------
105             *----------------------------------------------------------------*/
106             softfloat_raiseFlags(
107                 softfloat_flag_overflow | softfloat_flag_inexact );
108             if (
109                    roundNearEven
110                 || (roundingMode == softfloat_round_near_maxMag)
111                 || (roundingMode
112                         == (sign ? softfloat_round_min : softfloat_round_max))
113             ) {
114                 ui = packToF128UI96( sign, 0x7FFF, 0 );
115                 uj = 0;
116             } else {
117                 ui = packToF128UI96( sign, 0x7FFE, 0x0000FFFF );
118                 uj = 0xFFFFFFFF;
119             }
120             zWPtr[indexWordHi( 4 )] = ui;
121             zWPtr[indexWord( 4, 2 )] = uj;
122             zWPtr[indexWord( 4, 1 )] = uj;
123             zWPtr[indexWord( 4, 0 )] = uj;
124             return;
125         }
126     }
127     /*------------------------------------------------------------------------
128     *------------------------------------------------------------------------*/
129     uj = extSigPtr[indexWord( 5, 1 )];
130     if ( sigExtra ) {
131         softfloat_exceptionFlags |= softfloat_flag_inexact;
132 #ifdef SOFTFLOAT_ROUND_ODD
133         if ( roundingMode == softfloat_round_odd ) {
134             uj |= 1;
135             goto noIncrementPackReturn;
136         }
137 #endif
138     }
139     if ( doIncrement ) {
140         ++uj;
141         if ( uj ) {
142             if ( ! (sigExtra & 0x7FFFFFFF) && roundNearEven ) uj &= ~1;
143             zWPtr[indexWord( 4, 2 )] = extSigPtr[indexWord( 5, 3 )];
144             zWPtr[indexWord( 4, 1 )] = extSigPtr[indexWord( 5, 2 )];
145             zWPtr[indexWord( 4, 0 )] = uj;
146             ui = extSigPtr[indexWordHi( 5 )];
147         } else {
148             zWPtr[indexWord( 4, 0 )] = uj;
149             ui = extSigPtr[indexWord( 5, 2 )] + 1;
150             zWPtr[indexWord( 4, 1 )] = ui;
151             uj = extSigPtr[indexWord( 5, 3 )];
152             if ( ui ) {
153                 zWPtr[indexWord( 4, 2 )] = uj;
154                 ui = extSigPtr[indexWordHi( 5 )];
155             } else {
156                 ++uj;
157                 zWPtr[indexWord( 4, 2 )] = uj;
158                 ui = extSigPtr[indexWordHi( 5 )];
159                 if ( ! uj ) ++ui;
160             }
161         }
162     } else {
163  noIncrementPackReturn:
164         zWPtr[indexWord( 4, 0 )] = uj;
165         ui = extSigPtr[indexWord( 5, 2 )];
166         zWPtr[indexWord( 4, 1 )] = ui;
167         uj |= ui;
168         ui = extSigPtr[indexWord( 5, 3 )];
169         zWPtr[indexWord( 4, 2 )] = ui;
170         uj |= ui;
171         ui = extSigPtr[indexWordHi( 5 )];
172         uj |= ui;
173         if ( ! uj ) exp = 0;
174     }
175     zWPtr[indexWordHi( 4 )] = packToF128UI96( sign, exp, ui );
176 
177 }
178 
179