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
44float32_t f32_div( float32_t a, float32_t b )
45{
46    union ui32_f32 uA;
47    uint_fast32_t uiA;
48    bool signA;
49    int_fast16_t expA;
50    uint_fast32_t sigA;
51    union ui32_f32 uB;
52    uint_fast32_t uiB;
53    bool signB;
54    int_fast16_t expB;
55    uint_fast32_t sigB;
56    bool signZ;
57    struct exp16_sig32 normExpSig;
58    int_fast16_t expZ;
59#ifdef SOFTFLOAT_FAST_DIV64TO32
60    uint_fast64_t sig64A;
61    uint_fast32_t sigZ;
62#else
63    uint_fast32_t sigZ;
64    uint_fast64_t rem;
65#endif
66    uint_fast32_t uiZ;
67    union ui32_f32 uZ;
68
69    /*------------------------------------------------------------------------
70    *------------------------------------------------------------------------*/
71    uA.f = a;
72    uiA = uA.ui;
73    signA = signF32UI( uiA );
74    expA  = expF32UI( uiA );
75    sigA  = fracF32UI( uiA );
76    uB.f = b;
77    uiB = uB.ui;
78    signB = signF32UI( uiB );
79    expB  = expF32UI( uiB );
80    sigB  = fracF32UI( uiB );
81    signZ = signA ^ signB;
82    /*------------------------------------------------------------------------
83    *------------------------------------------------------------------------*/
84    if ( expA == 0xFF ) {
85        if ( sigA ) goto propagateNaN;
86        if ( expB == 0xFF ) {
87            if ( sigB ) goto propagateNaN;
88            goto invalid;
89        }
90        goto infinity;
91    }
92    if ( expB == 0xFF ) {
93        if ( sigB ) goto propagateNaN;
94        goto zero;
95    }
96    /*------------------------------------------------------------------------
97    *------------------------------------------------------------------------*/
98    if ( ! expB ) {
99        if ( ! sigB ) {
100            if ( ! (expA | sigA) ) goto invalid;
101            softfloat_raiseFlags( softfloat_flag_infinite );
102            goto infinity;
103        }
104        normExpSig = softfloat_normSubnormalF32Sig( sigB );
105        expB = normExpSig.exp;
106        sigB = normExpSig.sig;
107    }
108    if ( ! expA ) {
109        if ( ! sigA ) goto zero;
110        normExpSig = softfloat_normSubnormalF32Sig( sigA );
111        expA = normExpSig.exp;
112        sigA = normExpSig.sig;
113    }
114    /*------------------------------------------------------------------------
115    *------------------------------------------------------------------------*/
116    expZ = expA - expB + 0x7E;
117    sigA |= 0x00800000;
118    sigB |= 0x00800000;
119#ifdef SOFTFLOAT_FAST_DIV64TO32
120    if ( sigA < sigB ) {
121        --expZ;
122        sig64A = (uint_fast64_t) sigA<<31;
123    } else {
124        sig64A = (uint_fast64_t) sigA<<30;
125    }
126    sigZ = sig64A / sigB;
127    if ( ! (sigZ & 0x3F) ) sigZ |= ((uint_fast64_t) sigB * sigZ != sig64A);
128#else
129    if ( sigA < sigB ) {
130        --expZ;
131        sigA <<= 8;
132    } else {
133        sigA <<= 7;
134    }
135    sigB <<= 8;
136    sigZ = ((uint_fast64_t) sigA * softfloat_approxRecip32_1( sigB ))>>32;
137    /*------------------------------------------------------------------------
138    *------------------------------------------------------------------------*/
139    sigZ += 2;
140    if ( (sigZ & 0x3F) < 2 ) {
141        sigZ &= ~3;
142#ifdef SOFTFLOAT_FAST_INT64
143        rem = ((uint_fast64_t) sigA<<31) - (uint_fast64_t) sigZ * sigB;
144#else
145        rem = ((uint_fast64_t) sigA<<32) - (uint_fast64_t) (sigZ<<1) * sigB;
146#endif
147        if ( rem & UINT64_C( 0x8000000000000000 ) ) {
148            sigZ -= 4;
149        } else {
150            if ( rem ) sigZ |= 1;
151        }
152    }
153#endif
154    return softfloat_roundPackToF32( signZ, expZ, sigZ );
155    /*------------------------------------------------------------------------
156    *------------------------------------------------------------------------*/
157 propagateNaN:
158    uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
159    goto uiZ;
160    /*------------------------------------------------------------------------
161    *------------------------------------------------------------------------*/
162 invalid:
163    softfloat_raiseFlags( softfloat_flag_invalid );
164    uiZ = defaultNaNF32UI;
165    goto uiZ;
166    /*------------------------------------------------------------------------
167    *------------------------------------------------------------------------*/
168 infinity:
169    uiZ = packToF32UI( signZ, 0xFF, 0 );
170    goto uiZ;
171    /*------------------------------------------------------------------------
172    *------------------------------------------------------------------------*/
173 zero:
174    uiZ = packToF32UI( signZ, 0, 0 );
175 uiZ:
176    uZ.ui = uiZ;
177    return uZ.f;
178
179}
180
181