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 The Regents of the University of California.
8 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 "specialize.h"
42 #include "softfloat.h"
43
extF80_div(extFloat80_t a,extFloat80_t b)44 extFloat80_t extF80_div( extFloat80_t a, extFloat80_t b )
45 {
46 union { struct extFloat80M s; extFloat80_t f; } uA;
47 uint_fast16_t uiA64;
48 uint_fast64_t uiA0;
49 bool signA;
50 int_fast32_t expA;
51 uint_fast64_t sigA;
52 union { struct extFloat80M s; extFloat80_t f; } uB;
53 uint_fast16_t uiB64;
54 uint_fast64_t uiB0;
55 bool signB;
56 int_fast32_t expB;
57 uint_fast64_t sigB;
58 bool signZ;
59 struct exp32_sig64 normExpSig;
60 int_fast32_t expZ;
61 struct uint128 rem;
62 uint_fast32_t recip32;
63 uint_fast64_t sigZ;
64 int ix;
65 uint_fast64_t q64;
66 uint_fast32_t q;
67 struct uint128 term;
68 uint_fast64_t sigZExtra;
69 struct uint128 uiZ;
70 uint_fast16_t uiZ64;
71 uint_fast64_t uiZ0;
72 union { struct extFloat80M s; extFloat80_t f; } uZ;
73
74 /*------------------------------------------------------------------------
75 *------------------------------------------------------------------------*/
76 uA.f = a;
77 uiA64 = uA.s.signExp;
78 uiA0 = uA.s.signif;
79 signA = signExtF80UI64( uiA64 );
80 expA = expExtF80UI64( uiA64 );
81 sigA = uiA0;
82 uB.f = b;
83 uiB64 = uB.s.signExp;
84 uiB0 = uB.s.signif;
85 signB = signExtF80UI64( uiB64 );
86 expB = expExtF80UI64( uiB64 );
87 sigB = uiB0;
88 signZ = signA ^ signB;
89 /*------------------------------------------------------------------------
90 *------------------------------------------------------------------------*/
91 if ( expA == 0x7FFF ) {
92 if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
93 if ( expB == 0x7FFF ) {
94 if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
95 goto invalid;
96 }
97 goto infinity;
98 }
99 if ( expB == 0x7FFF ) {
100 if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
101 goto zero;
102 }
103 /*------------------------------------------------------------------------
104 *------------------------------------------------------------------------*/
105 if ( ! expB ) expB = 1;
106 if ( ! (sigB & UINT64_C( 0x8000000000000000 )) ) {
107 if ( ! sigB ) {
108 if ( ! sigA ) goto invalid;
109 softfloat_raiseFlags( softfloat_flag_infinite );
110 goto infinity;
111 }
112 normExpSig = softfloat_normSubnormalExtF80Sig( sigB );
113 expB += normExpSig.exp;
114 sigB = normExpSig.sig;
115 }
116 if ( ! expA ) expA = 1;
117 if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
118 if ( ! sigA ) goto zero;
119 normExpSig = softfloat_normSubnormalExtF80Sig( sigA );
120 expA += normExpSig.exp;
121 sigA = normExpSig.sig;
122 }
123 /*------------------------------------------------------------------------
124 *------------------------------------------------------------------------*/
125 expZ = expA - expB + 0x3FFF;
126 if ( sigA < sigB ) {
127 --expZ;
128 rem = softfloat_shortShiftLeft128( 0, sigA, 32 );
129 } else {
130 rem = softfloat_shortShiftLeft128( 0, sigA, 31 );
131 }
132 recip32 = softfloat_approxRecip32_1( sigB>>32 );
133 sigZ = 0;
134 ix = 2;
135 for (;;) {
136 q64 = (uint_fast64_t) (uint32_t) (rem.v64>>2) * recip32;
137 q = (q64 + 0x80000000)>>32;
138 --ix;
139 if ( ix < 0 ) break;
140 rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
141 term = softfloat_mul64ByShifted32To128( sigB, q );
142 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
143 if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
144 --q;
145 rem = softfloat_add128( rem.v64, rem.v0, sigB>>32, sigB<<32 );
146 }
147 sigZ = (sigZ<<29) + q;
148 }
149 /*------------------------------------------------------------------------
150 *------------------------------------------------------------------------*/
151 if ( ((q + 1) & 0x3FFFFF) < 2 ) {
152 rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
153 term = softfloat_mul64ByShifted32To128( sigB, q );
154 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
155 term = softfloat_shortShiftLeft128( 0, sigB, 32 );
156 if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
157 --q;
158 rem = softfloat_add128( rem.v64, rem.v0, term.v64, term.v0 );
159 } else if ( softfloat_le128( term.v64, term.v0, rem.v64, rem.v0 ) ) {
160 ++q;
161 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
162 }
163 if ( rem.v64 | rem.v0 ) q |= 1;
164 }
165 /*------------------------------------------------------------------------
166 *------------------------------------------------------------------------*/
167 sigZ = (sigZ<<6) + (q>>23);
168 sigZExtra = (uint64_t) ((uint_fast64_t) q<<41);
169 return
170 softfloat_roundPackToExtF80(
171 signZ, expZ, sigZ, sigZExtra, extF80_roundingPrecision );
172 /*------------------------------------------------------------------------
173 *------------------------------------------------------------------------*/
174 propagateNaN:
175 uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
176 uiZ64 = uiZ.v64;
177 uiZ0 = uiZ.v0;
178 goto uiZ;
179 /*------------------------------------------------------------------------
180 *------------------------------------------------------------------------*/
181 invalid:
182 softfloat_raiseFlags( softfloat_flag_invalid );
183 uiZ64 = defaultNaNExtF80UI64;
184 uiZ0 = defaultNaNExtF80UI0;
185 goto uiZ;
186 /*------------------------------------------------------------------------
187 *------------------------------------------------------------------------*/
188 infinity:
189 uiZ64 = packToExtF80UI64( signZ, 0x7FFF );
190 uiZ0 = UINT64_C( 0x8000000000000000 );
191 goto uiZ;
192 /*------------------------------------------------------------------------
193 *------------------------------------------------------------------------*/
194 zero:
195 uiZ64 = packToExtF80UI64( signZ, 0 );
196 uiZ0 = 0;
197 uiZ:
198 uZ.s.signExp = uiZ64;
199 uZ.s.signif = uiZ0;
200 return uZ.f;
201
202 }
203
204