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
f64_div(float64_t a,float64_t b)45 float64_t f64_div( float64_t a, float64_t b )
46 {
47 union ui64_f64 uA;
48 uint_fast64_t uiA;
49 bool signA;
50 int_fast16_t expA;
51 uint_fast64_t sigA;
52 union ui64_f64 uB;
53 uint_fast64_t uiB;
54 bool signB;
55 int_fast16_t expB;
56 uint_fast64_t sigB;
57 bool signZ;
58 struct exp16_sig64 normExpSig;
59 int_fast16_t expZ;
60 uint32_t recip32, sig32Z, doubleTerm;
61 uint_fast64_t rem;
62 uint32_t q;
63 uint_fast64_t sigZ;
64 uint_fast64_t uiZ;
65 union ui64_f64 uZ;
66
67 /*------------------------------------------------------------------------
68 *------------------------------------------------------------------------*/
69 uA.f = a;
70 uiA = uA.ui;
71 signA = signF64UI( uiA );
72 expA = expF64UI( uiA );
73 sigA = fracF64UI( uiA );
74 uB.f = b;
75 uiB = uB.ui;
76 signB = signF64UI( uiB );
77 expB = expF64UI( uiB );
78 sigB = fracF64UI( uiB );
79 signZ = signA ^ signB;
80 /*------------------------------------------------------------------------
81 *------------------------------------------------------------------------*/
82 if ( expA == 0x7FF ) {
83 if ( sigA ) goto propagateNaN;
84 if ( expB == 0x7FF ) {
85 if ( sigB ) goto propagateNaN;
86 goto invalid;
87 }
88 goto infinity;
89 }
90 if ( expB == 0x7FF ) {
91 if ( sigB ) goto propagateNaN;
92 goto zero;
93 }
94 /*------------------------------------------------------------------------
95 *------------------------------------------------------------------------*/
96 if ( ! expB ) {
97 if ( ! sigB ) {
98 if ( ! (expA | sigA) ) goto invalid;
99 softfloat_raiseFlags( softfloat_flag_infinite );
100 goto infinity;
101 }
102 normExpSig = softfloat_normSubnormalF64Sig( sigB );
103 expB = normExpSig.exp;
104 sigB = normExpSig.sig;
105 }
106 if ( ! expA ) {
107 if ( ! sigA ) goto zero;
108 normExpSig = softfloat_normSubnormalF64Sig( sigA );
109 expA = normExpSig.exp;
110 sigA = normExpSig.sig;
111 }
112 /*------------------------------------------------------------------------
113 *------------------------------------------------------------------------*/
114 expZ = expA - expB + 0x3FE;
115 sigA |= UINT64_C( 0x0010000000000000 );
116 sigB |= UINT64_C( 0x0010000000000000 );
117 if ( sigA < sigB ) {
118 --expZ;
119 sigA <<= 11;
120 } else {
121 sigA <<= 10;
122 }
123 sigB <<= 11;
124 recip32 = softfloat_approxRecip32_1( sigB>>32 ) - 2;
125 sig32Z = ((uint32_t) (sigA>>32) * (uint_fast64_t) recip32)>>32;
126 doubleTerm = sig32Z<<1;
127 rem =
128 ((sigA - (uint_fast64_t) doubleTerm * (uint32_t) (sigB>>32))<<28)
129 - (uint_fast64_t) doubleTerm * ((uint32_t) sigB>>4);
130 q = (((uint32_t) (rem>>32) * (uint_fast64_t) recip32)>>32) + 4;
131 sigZ = ((uint_fast64_t) sig32Z<<32) + ((uint_fast64_t) q<<4);
132 /*------------------------------------------------------------------------
133 *------------------------------------------------------------------------*/
134 if ( (sigZ & 0x1FF) < 4<<4 ) {
135 q &= ~7;
136 sigZ &= ~(uint_fast64_t) 0x7F;
137 doubleTerm = q<<1;
138 rem =
139 ((rem - (uint_fast64_t) doubleTerm * (uint32_t) (sigB>>32))<<28)
140 - (uint_fast64_t) doubleTerm * ((uint32_t) sigB>>4);
141 if ( rem & UINT64_C( 0x8000000000000000 ) ) {
142 sigZ -= 1<<7;
143 } else {
144 if ( rem ) sigZ |= 1;
145 }
146 }
147 return softfloat_roundPackToF64( signZ, expZ, sigZ );
148 /*------------------------------------------------------------------------
149 *------------------------------------------------------------------------*/
150 propagateNaN:
151 uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
152 goto uiZ;
153 /*------------------------------------------------------------------------
154 *------------------------------------------------------------------------*/
155 invalid:
156 softfloat_raiseFlags( softfloat_flag_invalid );
157 uiZ = defaultNaNF64UI;
158 goto uiZ;
159 /*------------------------------------------------------------------------
160 *------------------------------------------------------------------------*/
161 infinity:
162 uiZ = packToF64UI( signZ, 0x7FF, 0 );
163 goto uiZ;
164 /*------------------------------------------------------------------------
165 *------------------------------------------------------------------------*/
166 zero:
167 uiZ = packToF64UI( signZ, 0, 0 );
168 uiZ:
169 uZ.ui = uiZ;
170 return uZ.f;
171
172 }
173
174