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
main(int,char **)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
44 float128_t f128_div( float128_t a, float128_t b )
45 {
46 union ui128_f128 uA;
47 uint_fast64_t uiA64, uiA0;
48 bool signA;
49 int_fast32_t expA;
50 struct uint128 sigA;
51 union ui128_f128 uB;
52 uint_fast64_t uiB64, uiB0;
53 bool signB;
54 int_fast32_t expB;
55 struct uint128 sigB;
56 bool signZ;
57 struct exp32_sig128 normExpSig;
58 int_fast32_t expZ;
59 struct uint128 rem;
60 uint_fast32_t recip32;
61 int ix;
62 uint_fast64_t q64;
63 uint_fast32_t q;
64 struct uint128 term;
65 uint_fast32_t qs[3];
66 uint_fast64_t sigZExtra;
67 struct uint128 sigZ, uiZ;
68 union ui128_f128 uZ;
69
70 /*------------------------------------------------------------------------
71 *------------------------------------------------------------------------*/
72 uA.f = a;
73 uiA64 = uA.ui.v64;
74 uiA0 = uA.ui.v0;
75 signA = signF128UI64( uiA64 );
76 expA = expF128UI64( uiA64 );
77 sigA.v64 = fracF128UI64( uiA64 );
78 sigA.v0 = uiA0;
79 uB.f = b;
80 uiB64 = uB.ui.v64;
81 uiB0 = uB.ui.v0;
82 signB = signF128UI64( uiB64 );
83 expB = expF128UI64( uiB64 );
84 sigB.v64 = fracF128UI64( uiB64 );
85 sigB.v0 = uiB0;
86 signZ = signA ^ signB;
87 /*------------------------------------------------------------------------
88 *------------------------------------------------------------------------*/
89 if ( expA == 0x7FFF ) {
90 if ( sigA.v64 | sigA.v0 ) goto propagateNaN;
91 if ( expB == 0x7FFF ) {
92 if ( sigB.v64 | sigB.v0 ) goto propagateNaN;
93 goto invalid;
94 }
95 goto infinity;
96 }
97 if ( expB == 0x7FFF ) {
98 if ( sigB.v64 | sigB.v0 ) goto propagateNaN;
99 goto zero;
100 }
101 /*------------------------------------------------------------------------
102 *------------------------------------------------------------------------*/
103 if ( ! expB ) {
104 if ( ! (sigB.v64 | sigB.v0) ) {
105 if ( ! (expA | sigA.v64 | sigA.v0) ) goto invalid;
106 softfloat_raiseFlags( softfloat_flag_infinite );
107 goto infinity;
108 }
109 normExpSig = softfloat_normSubnormalF128Sig( sigB.v64, sigB.v0 );
110 expB = normExpSig.exp;
111 sigB = normExpSig.sig;
112 }
113 if ( ! expA ) {
114 if ( ! (sigA.v64 | sigA.v0) ) goto zero;
115 normExpSig = softfloat_normSubnormalF128Sig( sigA.v64, sigA.v0 );
116 expA = normExpSig.exp;
117 sigA = normExpSig.sig;
118 }
119 /*------------------------------------------------------------------------
120 *------------------------------------------------------------------------*/
121 expZ = expA - expB + 0x3FFE;
122 sigA.v64 |= UINT64_C( 0x0001000000000000 );
123 sigB.v64 |= UINT64_C( 0x0001000000000000 );
124 rem = sigA;
125 if ( softfloat_lt128( sigA.v64, sigA.v0, sigB.v64, sigB.v0 ) ) {
126 --expZ;
127 rem = softfloat_add128( sigA.v64, sigA.v0, sigA.v64, sigA.v0 );
128 }
129 recip32 = softfloat_approxRecip32_1( sigB.v64>>17 );
130 ix = 3;
131 for (;;) {
132 q64 = (uint_fast64_t) (uint32_t) (rem.v64>>19) * recip32;
133 q = (q64 + 0x80000000)>>32;
134 --ix;
135 if ( ix < 0 ) break;
136 rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
137 term = softfloat_mul128By32( sigB.v64, sigB.v0, q );
138 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
139 if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
140 --q;
141 rem = softfloat_add128( rem.v64, rem.v0, sigB.v64, sigB.v0 );
142 }
143 qs[ix] = q;
144 }
145 /*------------------------------------------------------------------------
146 *------------------------------------------------------------------------*/
147 if ( ((q + 1) & 7) < 2 ) {
148 rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
149 term = softfloat_mul128By32( sigB.v64, sigB.v0, q );
150 rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
151 if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
152 --q;
153 rem = softfloat_add128( rem.v64, rem.v0, sigB.v64, sigB.v0 );
154 } else if ( softfloat_le128( sigB.v64, sigB.v0, rem.v64, rem.v0 ) ) {
155 ++q;
156 rem = softfloat_sub128( rem.v64, rem.v0, sigB.v64, sigB.v0 );
157 }
158 if ( rem.v64 | rem.v0 ) q |= 1;
159 }
160 /*------------------------------------------------------------------------
161 *------------------------------------------------------------------------*/
162 sigZExtra = (uint64_t) ((uint_fast64_t) q<<60);
163 term = softfloat_shortShiftLeft128( 0, qs[1], 54 );
164 sigZ =
165 softfloat_add128(
166 (uint_fast64_t) qs[2]<<19, ((uint_fast64_t) qs[0]<<25) + (q>>4),
167 term.v64, term.v0
168 );
169 return
170 softfloat_roundPackToF128( signZ, expZ, sigZ.v64, sigZ.v0, sigZExtra );
171 /*------------------------------------------------------------------------
172 *------------------------------------------------------------------------*/
173 propagateNaN:
174 uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 );
175 goto uiZ;
176 /*------------------------------------------------------------------------
177 *------------------------------------------------------------------------*/
178 invalid:
179 softfloat_raiseFlags( softfloat_flag_invalid );
180 uiZ.v64 = defaultNaNF128UI64;
181 uiZ.v0 = defaultNaNF128UI0;
182 goto uiZ;
183 /*------------------------------------------------------------------------
184 *------------------------------------------------------------------------*/
185 infinity:
186 uiZ.v64 = packToF128UI64( signZ, 0x7FFF, 0 );
187 goto uiZ0;
188 /*------------------------------------------------------------------------
189 *------------------------------------------------------------------------*/
190 zero:
191 uiZ.v64 = packToF128UI64( signZ, 0, 0 );
192 uiZ0:
193 uiZ.v0 = 0;
194 uiZ:
195 uZ.ui = uiZ;
196 return uZ.f;
197
198 }
199
200