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
f64_div(float64_t a,float64_t b)44 float64_t f64_div( float64_t a, float64_t b )
45 {
46 union ui64_f64 uA;
47 uint_fast64_t uiA;
48 bool signA;
49 int_fast16_t expA;
50 uint_fast64_t sigA;
51 union ui64_f64 uB;
52 uint_fast64_t uiB;
53 bool signB;
54 int_fast16_t expB;
55 uint_fast64_t sigB;
56 bool signZ;
57 struct exp16_sig64 normExpSig;
58 int_fast16_t expZ;
59 uint32_t recip32, sig32Z, doubleTerm;
60 uint_fast64_t rem;
61 uint32_t q;
62 uint_fast64_t sigZ;
63 uint_fast64_t uiZ;
64 union ui64_f64 uZ;
65
66 /*------------------------------------------------------------------------
67 *------------------------------------------------------------------------*/
68 uA.f = a;
69 uiA = uA.ui;
70 signA = signF64UI( uiA );
71 expA = expF64UI( uiA );
72 sigA = fracF64UI( uiA );
73 uB.f = b;
74 uiB = uB.ui;
75 signB = signF64UI( uiB );
76 expB = expF64UI( uiB );
77 sigB = fracF64UI( uiB );
78 signZ = signA ^ signB;
79 /*------------------------------------------------------------------------
80 *------------------------------------------------------------------------*/
81 if ( expA == 0x7FF ) {
82 if ( sigA ) goto propagateNaN;
83 if ( expB == 0x7FF ) {
84 if ( sigB ) goto propagateNaN;
85 goto invalid;
86 }
87 goto infinity;
88 }
89 if ( expB == 0x7FF ) {
90 if ( sigB ) goto propagateNaN;
91 goto zero;
92 }
93 /*------------------------------------------------------------------------
94 *------------------------------------------------------------------------*/
95 if ( ! expB ) {
96 if ( ! sigB ) {
97 if ( ! (expA | sigA) ) goto invalid;
98 softfloat_raiseFlags( softfloat_flag_infinite );
99 goto infinity;
100 }
101 normExpSig = softfloat_normSubnormalF64Sig( sigB );
102 expB = normExpSig.exp;
103 sigB = normExpSig.sig;
104 }
105 if ( ! expA ) {
106 if ( ! sigA ) goto zero;
107 normExpSig = softfloat_normSubnormalF64Sig( sigA );
108 expA = normExpSig.exp;
109 sigA = normExpSig.sig;
110 }
111 /*------------------------------------------------------------------------
112 *------------------------------------------------------------------------*/
113 expZ = expA - expB + 0x3FE;
114 sigA |= UINT64_C( 0x0010000000000000 );
115 sigB |= UINT64_C( 0x0010000000000000 );
116 if ( sigA < sigB ) {
117 --expZ;
118 sigA <<= 11;
119 } else {
120 sigA <<= 10;
121 }
122 sigB <<= 11;
123 recip32 = softfloat_approxRecip32_1( sigB>>32 ) - 2;
124 sig32Z = ((uint32_t) (sigA>>32) * (uint_fast64_t) recip32)>>32;
125 doubleTerm = sig32Z<<1;
126 rem =
127 ((sigA - (uint_fast64_t) doubleTerm * (uint32_t) (sigB>>32))<<28)
128 - (uint_fast64_t) doubleTerm * ((uint32_t) sigB>>4);
129 q = (((uint32_t) (rem>>32) * (uint_fast64_t) recip32)>>32) + 4;
130 sigZ = ((uint_fast64_t) sig32Z<<32) + ((uint_fast64_t) q<<4);
131 /*------------------------------------------------------------------------
132 *------------------------------------------------------------------------*/
133 if ( (sigZ & 0x1FF) < 4<<4 ) {
134 q &= ~7;
135 sigZ &= ~(uint_fast64_t) 0x7F;
136 doubleTerm = q<<1;
137 rem =
138 ((rem - (uint_fast64_t) doubleTerm * (uint32_t) (sigB>>32))<<28)
139 - (uint_fast64_t) doubleTerm * ((uint32_t) sigB>>4);
140 if ( rem & UINT64_C( 0x8000000000000000 ) ) {
141 sigZ -= 1<<7;
142 } else {
143 if ( rem ) sigZ |= 1;
144 }
145 }
146 return softfloat_roundPackToF64( signZ, expZ, sigZ );
147 /*------------------------------------------------------------------------
148 *------------------------------------------------------------------------*/
149 propagateNaN:
150 uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
151 goto uiZ;
152 /*------------------------------------------------------------------------
153 *------------------------------------------------------------------------*/
154 invalid:
155 softfloat_raiseFlags( softfloat_flag_invalid );
156 uiZ = defaultNaNF64UI;
157 goto uiZ;
158 /*------------------------------------------------------------------------
159 *------------------------------------------------------------------------*/
160 infinity:
161 uiZ = packToF64UI( signZ, 0x7FF, 0 );
162 goto uiZ;
163 /*------------------------------------------------------------------------
164 *------------------------------------------------------------------------*/
165 zero:
166 uiZ = packToF64UI( signZ, 0, 0 );
167 uiZ:
168 uZ.ui = uiZ;
169 return uZ.f;
170
171 }
172
173