1
2/*============================================================================
3
4This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
5Package, Release 3e, by John R. Hauser.
6
7Copyright 2011, 2012, 2013, 2014 The Regents of the University of California.
8All rights reserved.
9
10Redistribution and use in source and binary forms, with or without
11modification, 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
24THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
25EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
27DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
28DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31ON 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
33SOFTWARE, 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
44float64_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