1 // SPDX-License-Identifier: BSD-3-Clause
2
3 /*============================================================================
4
5 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
6 Package, Release 3a, by John R. Hauser.
7
8 Copyright 2011, 2012, 2013, 2014 The Regents of the University of California.
9 All rights reserved.
10
11 Redistribution and use in source and binary forms, with or without
12 modification, are permitted provided that the following conditions are met:
13
14 1. Redistributions of source code must retain the above copyright notice,
15 this list of conditions, and the following disclaimer.
16
17 2. Redistributions in binary form must reproduce the above copyright notice,
18 this list of conditions, and the following disclaimer in the documentation
19 and/or other materials provided with the distribution.
20
21 3. Neither the name of the University nor the names of its contributors may
22 be used to endorse or promote products derived from this software without
23 specific prior written permission.
24
25 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
26 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
27 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
28 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
29 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
30 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
31 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
32 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35
36 =============================================================================*/
37
38 #include <stdbool.h>
39 #include <stdint.h>
40 #include "platform.h"
41 #include "internals.h"
42 #include "specialize.h"
43 #include "softfloat.h"
44
extF80_div(extFloat80_t a,extFloat80_t b)45 extFloat80_t extF80_div( extFloat80_t a, extFloat80_t b )
46 {
47 union { struct extFloat80M s; extFloat80_t f; } uA;
48 uint_fast16_t uiA64;
49 uint_fast64_t uiA0;
50 bool signA;
51 int_fast32_t expA;
52 uint_fast64_t sigA;
53 union { struct extFloat80M s; extFloat80_t f; } uB;
54 uint_fast16_t uiB64;
55 uint_fast64_t uiB0;
56 bool signB;
57 int_fast32_t expB;
58 uint_fast64_t sigB;
59 bool signZ;
60 struct exp32_sig64 normExpSig;
61 int_fast32_t expZ;
62 struct uint128 rem;
63 uint_fast32_t recip32;
64 uint_fast64_t sigZ;
65 int ix;
66 uint_fast64_t q64;
67 uint_fast32_t q;
68 struct uint128 term;
69 uint_fast64_t sigZExtra;
70 struct uint128 uiZ;
71 uint_fast16_t uiZ64;
72 uint_fast64_t uiZ0;
73 union { struct extFloat80M s; extFloat80_t f; } uZ;
74
75 /*------------------------------------------------------------------------
76 *------------------------------------------------------------------------*/
77 uA.f = a;
78 uiA64 = uA.s.signExp;
79 uiA0 = uA.s.signif;
80 signA = signExtF80UI64( uiA64 );
81 expA = expExtF80UI64( uiA64 );
82 sigA = uiA0;
83 uB.f = b;
84 uiB64 = uB.s.signExp;
85 uiB0 = uB.s.signif;
86 signB = signExtF80UI64( uiB64 );
87 expB = expExtF80UI64( uiB64 );
88 sigB = uiB0;
89 signZ = signA ^ signB;
90 /*------------------------------------------------------------------------
91 *------------------------------------------------------------------------*/
92 if ( expA == 0x7FFF ) {
93 if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
94 if ( expB == 0x7FFF ) {
95 if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
96 goto invalid;
97 }
98 goto infinity;
99 }
100 if ( expB == 0x7FFF ) {
101 if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
102 goto zero;
103 }
104 /*------------------------------------------------------------------------
105 *------------------------------------------------------------------------*/
106 if ( ! expB ) expB = 1;
107 if ( ! (sigB & UINT64_C( 0x8000000000000000 )) ) {
108 if ( ! sigB ) {
109 if ( ! sigA ) goto invalid;
110 softfloat_raiseFlags( softfloat_flag_infinite );
111 goto infinity;
112 }
113 normExpSig = softfloat_normSubnormalExtF80Sig( sigB );
114 expB += normExpSig.exp;
115 sigB = normExpSig.sig;
116 }
117 if ( ! expA ) expA = 1;
118 if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
119 if ( ! sigA ) goto zero;
120 normExpSig = softfloat_normSubnormalExtF80Sig( sigA );
121 expA += normExpSig.exp;
122 sigA = normExpSig.sig;
123 }
124 /*------------------------------------------------------------------------
125 *------------------------------------------------------------------------*/
126 expZ = expA - expB + 0x3FFF;
127 if ( sigA < sigB ) {
128 --expZ;
129 rem = softfloat_shortShiftLeft128( 0, sigA, 32 );
130 } else {
131 rem = softfloat_shortShiftLeft128( 0, sigA, 31 );
132 }
133 recip32 = softfloat_approxRecip32_1( sigB>>32 );
134 sigZ = 0;
135 ix = 2;
136 for (;;) {
137 q64 = (uint_fast64_t) (uint32_t) (rem.v64>>2) * recip32;
138 q = (q64 + 0x80000000)>>32;
139 --ix;
140 if ( ix < 0 ) break;
141 rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
142 term = softfloat_mul64ByShifted32To128( sigB, q );
143 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
144 if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
145 --q;
146 rem = softfloat_add128( rem.v64, rem.v0, sigB>>32, sigB<<32 );
147 }
148 sigZ = (sigZ<<29) + q;
149 }
150 /*------------------------------------------------------------------------
151 *------------------------------------------------------------------------*/
152 if ( ((q + 1) & 0x3FFFFF) < 2 ) {
153 rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
154 term = softfloat_mul64ByShifted32To128( sigB, q );
155 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
156 term = softfloat_shortShiftLeft128( 0, sigB, 32 );
157 if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
158 --q;
159 rem = softfloat_add128( rem.v64, rem.v0, term.v64, term.v0 );
160 } else if ( softfloat_le128( term.v64, term.v0, rem.v64, rem.v0 ) ) {
161 ++q;
162 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
163 }
164 if ( rem.v64 | rem.v0 ) q |= 1;
165 }
166 /*------------------------------------------------------------------------
167 *------------------------------------------------------------------------*/
168 sigZ = (sigZ<<6) + (q>>23);
169 sigZExtra = (uint64_t) ((uint_fast64_t) q<<41);
170 return
171 softfloat_roundPackToExtF80(
172 signZ, expZ, sigZ, sigZExtra, extF80_roundingPrecision );
173 /*------------------------------------------------------------------------
174 *------------------------------------------------------------------------*/
175 propagateNaN:
176 uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
177 uiZ64 = uiZ.v64;
178 uiZ0 = uiZ.v0;
179 goto uiZ;
180 /*------------------------------------------------------------------------
181 *------------------------------------------------------------------------*/
182 invalid:
183 softfloat_raiseFlags( softfloat_flag_invalid );
184 uiZ64 = defaultNaNExtF80UI64;
185 uiZ0 = defaultNaNExtF80UI0;
186 goto uiZ;
187 /*------------------------------------------------------------------------
188 *------------------------------------------------------------------------*/
189 infinity:
190 uiZ64 = packToExtF80UI64( signZ, 0x7FFF );
191 uiZ0 = UINT64_C( 0x8000000000000000 );
192 goto uiZ;
193 /*------------------------------------------------------------------------
194 *------------------------------------------------------------------------*/
195 zero:
196 uiZ64 = packToExtF80UI64( signZ, 0 );
197 uiZ0 = 0;
198 uiZ:
199 uZ.s.signExp = uiZ64;
200 uZ.s.signif = uiZ0;
201 return uZ.f;
202
203 }
204
205