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, 2015, 2016 The Regents of the University of
8California.  All 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
44#ifdef SOFTFLOAT_FAST_INT64
45
46void
47 extF80M_div(
48     const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr )
49{
50
51    *zPtr = extF80_div( *aPtr, *bPtr );
52
53}
54
55#else
56
57void
58 extF80M_div(
59     const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr )
60{
61    const struct extFloat80M *aSPtr, *bSPtr;
62    struct extFloat80M *zSPtr;
63    uint_fast16_t uiA64;
64    int32_t expA;
65    uint_fast16_t uiB64;
66    int32_t expB;
67    bool signZ;
68    uint64_t sigA, x64;
69    int32_t expZ;
70    int shiftDist;
71    uint32_t y[3], recip32, sigB[3];
72    int ix;
73    uint32_t q, qs[2];
74    uint_fast16_t uiZ64;
75    uint64_t uiZ0;
76
77    /*------------------------------------------------------------------------
78    *------------------------------------------------------------------------*/
79    aSPtr = (const struct extFloat80M *) aPtr;
80    bSPtr = (const struct extFloat80M *) bPtr;
81    zSPtr = (struct extFloat80M *) zPtr;
82    /*------------------------------------------------------------------------
83    *------------------------------------------------------------------------*/
84    uiA64 = aSPtr->signExp;
85    expA = expExtF80UI64( uiA64 );
86    uiB64 = bSPtr->signExp;
87    expB = expExtF80UI64( uiB64 );
88    signZ = signExtF80UI64( uiA64 ) ^ signExtF80UI64( uiB64 );
89    /*------------------------------------------------------------------------
90    *------------------------------------------------------------------------*/
91    if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) {
92        if ( softfloat_tryPropagateNaNExtF80M( aSPtr, bSPtr, zSPtr ) ) return;
93        if ( expA == 0x7FFF ) {
94            if ( expB == 0x7FFF ) goto invalid;
95            goto infinity;
96        }
97        goto zero;
98    }
99    /*------------------------------------------------------------------------
100    *------------------------------------------------------------------------*/
101    sigA = aSPtr->signif;
102    x64 = bSPtr->signif;
103    if ( ! expB ) expB = 1;
104    if ( ! (x64 & UINT64_C( 0x8000000000000000 )) ) {
105        if ( ! x64 ) {
106            if ( ! sigA ) goto invalid;
107            softfloat_raiseFlags( softfloat_flag_infinite );
108            goto infinity;
109        }
110        expB += softfloat_normExtF80SigM( &x64 );
111    }
112    if ( ! expA ) expA = 1;
113    if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
114        if ( ! sigA ) goto zero;
115        expA += softfloat_normExtF80SigM( &sigA );
116    }
117    /*------------------------------------------------------------------------
118    *------------------------------------------------------------------------*/
119    expZ = expA - expB + 0x3FFF;
120    shiftDist = 29;
121    if ( sigA < x64 ) {
122        --expZ;
123        shiftDist = 30;
124    }
125    softfloat_shortShiftLeft64To96M( sigA, shiftDist, y );
126    recip32 = softfloat_approxRecip32_1( x64>>32 );
127    sigB[indexWord( 3, 0 )] = (uint32_t) x64<<30;
128    x64 >>= 2;
129    sigB[indexWord( 3, 2 )] = x64>>32;
130    sigB[indexWord( 3, 1 )] = x64;
131    ix = 2;
132    for (;;) {
133        x64 = (uint64_t) y[indexWordHi( 3 )] * recip32;
134        q = (x64 + 0x80000000)>>32;
135        --ix;
136        if ( ix < 0 ) break;
137        softfloat_remStep96MBy32( y, 29, sigB, q, y );
138        if ( y[indexWordHi( 3 )] & 0x80000000 ) {
139            --q;
140            softfloat_add96M( y, sigB, y );
141        }
142        qs[ix] = q;
143    }
144    /*------------------------------------------------------------------------
145    *------------------------------------------------------------------------*/
146    if ( ((q + 1) & 0x3FFFFF) < 2 ) {
147        softfloat_remStep96MBy32( y, 29, sigB, q, y );
148        if ( y[indexWordHi( 3 )] & 0x80000000 ) {
149            --q;
150            softfloat_add96M( y, sigB, y );
151        } else if ( softfloat_compare96M( sigB, y ) <= 0 ) {
152            ++q;
153            softfloat_sub96M( y, sigB, y );
154        }
155        if (
156            y[indexWordLo( 3 )] || y[indexWord( 3, 1 )] || y[indexWord( 3, 2 )]
157        ) {
158            q |= 1;
159        }
160    }
161    /*------------------------------------------------------------------------
162    *------------------------------------------------------------------------*/
163    x64 = (uint64_t) q<<9;
164    y[indexWord( 3, 0 )] = x64;
165    x64 = ((uint64_t) qs[0]<<6) + (x64>>32);
166    y[indexWord( 3, 1 )] = x64;
167    y[indexWord( 3, 2 )] = (qs[1]<<3) + (x64>>32);
168    softfloat_roundPackMToExtF80M(
169        signZ, expZ, y, extF80_roundingPrecision, zSPtr );
170    return;
171    /*------------------------------------------------------------------------
172    *------------------------------------------------------------------------*/
173 invalid:
174    softfloat_invalidExtF80M( zSPtr );
175    return;
176    /*------------------------------------------------------------------------
177    *------------------------------------------------------------------------*/
178 infinity:
179    uiZ64 = packToExtF80UI64( signZ, 0x7FFF );
180    uiZ0  = UINT64_C( 0x8000000000000000 );
181    goto uiZ;
182    /*------------------------------------------------------------------------
183    *------------------------------------------------------------------------*/
184 zero:
185    uiZ64 = packToExtF80UI64( signZ, 0 );
186    uiZ0  = 0;
187 uiZ:
188    zSPtr->signExp = uiZ64;
189    zSPtr->signif  = uiZ0;
190
191}
192
193#endif
194
195