VirtualBox

source: vbox/trunk/src/libs/softfloat-3e/source/extF80M_rem.c@ 96145

Last change on this file since 96145 was 94558, checked in by vboxsync, 3 years ago

VMM/IEM,libs/softfloat: Don't use global variables in SoftFloat, pass in a state pointer to (almost) all functions instead. Started on fsqrt instruction implementation. bugref:9898

  • Property svn:eol-style set to native
File size: 7.7 KB
Line 
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 The Regents of the University of California.
8All 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_rem(
48 const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr SOFTFLOAT_STATE_DECL_COMMA )
49{
50
51 *zPtr = extF80_rem( *aPtr, *bPtr SOFTFLOAT_STATE_ARG_COMMA );
52
53}
54
55#else
56
57void
58 extF80M_rem(
59 const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr SOFTFLOAT_STATE_DECL_COMMA )
60{
61 const struct extFloat80M *aSPtr, *bSPtr;
62 struct extFloat80M *zSPtr;
63 uint_fast16_t uiA64;
64 int32_t expA, expB;
65 uint64_t x64;
66 bool signRem;
67 uint64_t sigA;
68 int32_t expDiff;
69 uint32_t rem[3], x[3], sig32B, q, recip32, rem2[3], *remPtr, *altRemPtr;
70 uint32_t *newRemPtr, wordMeanRem;
71
72 /*------------------------------------------------------------------------
73 *------------------------------------------------------------------------*/
74 aSPtr = (const struct extFloat80M *) aPtr;
75 bSPtr = (const struct extFloat80M *) bPtr;
76 zSPtr = (struct extFloat80M *) zPtr;
77 /*------------------------------------------------------------------------
78 *------------------------------------------------------------------------*/
79 uiA64 = aSPtr->signExp;
80 expA = expExtF80UI64( uiA64 );
81 expB = expExtF80UI64( bSPtr->signExp );
82 /*------------------------------------------------------------------------
83 *------------------------------------------------------------------------*/
84 if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) {
85 if ( softfloat_tryPropagateNaNExtF80M( aSPtr, bSPtr, zSPtr SOFTFLOAT_STATE_ARG_COMMA ) ) return;
86 if ( expA == 0x7FFF ) goto invalid;
87 /*--------------------------------------------------------------------
88 | If we get here, then argument b is an infinity and `expB' is 0x7FFF;
89 | Doubling `expB' is an easy way to ensure that `expDiff' later is
90 | less than -1, which will result in returning a canonicalized version
91 | of argument a.
92 *--------------------------------------------------------------------*/
93 expB += expB;
94 }
95 /*------------------------------------------------------------------------
96 *------------------------------------------------------------------------*/
97 if ( ! expB ) expB = 1;
98 x64 = bSPtr->signif;
99 if ( ! (x64 & UINT64_C( 0x8000000000000000 )) ) {
100 if ( ! x64 ) goto invalid;
101 expB += softfloat_normExtF80SigM( &x64 );
102 }
103 signRem = signExtF80UI64( uiA64 );
104 if ( ! expA ) expA = 1;
105 sigA = aSPtr->signif;
106 if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
107 if ( ! sigA ) {
108 expA = 0;
109 goto copyA;
110 }
111 expA += softfloat_normExtF80SigM( &sigA );
112 }
113 /*------------------------------------------------------------------------
114 *------------------------------------------------------------------------*/
115 expDiff = expA - expB;
116 if ( expDiff < -1 ) goto copyA;
117 rem[indexWord( 3, 2 )] = sigA>>34;
118 rem[indexWord( 3, 1 )] = sigA>>2;
119 rem[indexWord( 3, 0 )] = (uint32_t) sigA<<30;
120 x[indexWord( 3, 0 )] = (uint32_t) x64<<30;
121 sig32B = x64>>32;
122 x64 >>= 2;
123 x[indexWord( 3, 2 )] = x64>>32;
124 x[indexWord( 3, 1 )] = x64;
125 if ( expDiff < 1 ) {
126 if ( expDiff ) {
127 --expB;
128 softfloat_add96M( x, x, x );
129 q = 0;
130 } else {
131 q = (softfloat_compare96M( x, rem ) <= 0);
132 if ( q ) softfloat_sub96M( rem, x, rem );
133 }
134 } else {
135 recip32 = softfloat_approxRecip32_1( sig32B );
136 expDiff -= 30;
137 for (;;) {
138 x64 = (uint64_t) rem[indexWordHi( 3 )] * recip32;
139 if ( expDiff < 0 ) break;
140 q = (x64 + 0x80000000)>>32;
141 softfloat_remStep96MBy32( rem, 29, x, q, rem );
142 if ( rem[indexWordHi( 3 )] & 0x80000000 ) {
143 softfloat_add96M( rem, x, rem );
144 }
145 expDiff -= 29;
146 }
147 /*--------------------------------------------------------------------
148 | (`expDiff' cannot be less than -29 here.)
149 *--------------------------------------------------------------------*/
150 q = (uint32_t) (x64>>32)>>(~expDiff & 31);
151 softfloat_remStep96MBy32( rem, expDiff + 30, x, q, rem );
152 if ( rem[indexWordHi( 3 )] & 0x80000000 ) {
153 remPtr = rem;
154 altRemPtr = rem2;
155 softfloat_add96M( remPtr, x, altRemPtr );
156 goto selectRem;
157 }
158 }
159 /*------------------------------------------------------------------------
160 *------------------------------------------------------------------------*/
161 remPtr = rem;
162 altRemPtr = rem2;
163 do {
164 ++q;
165 newRemPtr = altRemPtr;
166 softfloat_sub96M( remPtr, x, newRemPtr );
167 altRemPtr = remPtr;
168 remPtr = newRemPtr;
169 } while ( ! (remPtr[indexWordHi( 3 )] & 0x80000000) );
170 selectRem:
171 softfloat_add96M( remPtr, altRemPtr, x );
172 wordMeanRem = x[indexWordHi( 3 )];
173 if (
174 (wordMeanRem & 0x80000000)
175 || (! wordMeanRem && (q & 1) && ! x[indexWord( 3, 0 )]
176 && ! x[indexWord( 3, 1 )])
177 ) {
178 remPtr = altRemPtr;
179 }
180 if ( remPtr[indexWordHi( 3 )] & 0x80000000 ) {
181 signRem = ! signRem;
182 softfloat_negX96M( remPtr );
183 }
184 softfloat_normRoundPackMToExtF80M( signRem, expB + 2, remPtr, 80, zSPtr SOFTFLOAT_STATE_ARG_COMMA );
185 return;
186 /*------------------------------------------------------------------------
187 *------------------------------------------------------------------------*/
188 invalid:
189 softfloat_invalidExtF80M( zSPtr SOFTFLOAT_STATE_ARG_COMMA );
190 return;
191 /*------------------------------------------------------------------------
192 *------------------------------------------------------------------------*/
193 copyA:
194 if ( expA < 1 ) {
195 sigA >>= 1 - expA;
196 expA = 0;
197 }
198 zSPtr->signExp = packToExtF80UI64( signRem, expA );
199 zSPtr->signif = sigA;
200
201}
202
203#endif
204
Note: See TracBrowser for help on using the repository browser.

© 2024 Oracle Support Privacy / Do Not Sell My Info Terms of Use Trademark Policy Automated Access Etiquette