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
44float32_t
45 softfloat_mulAddF32(
46     uint_fast32_t uiA, uint_fast32_t uiB, uint_fast32_t uiC, uint_fast8_t op )
47{
48    bool signA;
49    int_fast16_t expA;
50    uint_fast32_t sigA;
51    bool signB;
52    int_fast16_t expB;
53    uint_fast32_t sigB;
54    bool signC;
55    int_fast16_t expC;
56    uint_fast32_t sigC;
57    bool signProd;
58    uint_fast32_t magBits, uiZ;
59    struct exp16_sig32 normExpSig;
60    int_fast16_t expProd;
61    uint_fast64_t sigProd;
62    bool signZ;
63    int_fast16_t expZ;
64    uint_fast32_t sigZ;
65    int_fast16_t expDiff;
66    uint_fast64_t sig64Z, sig64C;
67    int_fast8_t shiftDist;
68    union ui32_f32 uZ;
69
70    /*------------------------------------------------------------------------
71    *------------------------------------------------------------------------*/
72    signA = signF32UI( uiA );
73    expA  = expF32UI( uiA );
74    sigA  = fracF32UI( uiA );
75    signB = signF32UI( uiB );
76    expB  = expF32UI( uiB );
77    sigB  = fracF32UI( uiB );
78    signC = signF32UI( uiC ) ^ (op == softfloat_mulAdd_subC);
79    expC  = expF32UI( uiC );
80    sigC  = fracF32UI( uiC );
81    signProd = signA ^ signB ^ (op == softfloat_mulAdd_subProd);
82    /*------------------------------------------------------------------------
83    *------------------------------------------------------------------------*/
84    if ( expA == 0xFF ) {
85        if ( sigA || ((expB == 0xFF) && sigB) ) goto propagateNaN_ABC;
86        magBits = expB | sigB;
87        goto infProdArg;
88    }
89    if ( expB == 0xFF ) {
90        if ( sigB ) goto propagateNaN_ABC;
91        magBits = expA | sigA;
92        goto infProdArg;
93    }
94    if ( expC == 0xFF ) {
95        if ( sigC ) {
96            uiZ = 0;
97            goto propagateNaN_ZC;
98        }
99        uiZ = uiC;
100        goto uiZ;
101    }
102    /*------------------------------------------------------------------------
103    *------------------------------------------------------------------------*/
104    if ( ! expA ) {
105        if ( ! sigA ) goto zeroProd;
106        normExpSig = softfloat_normSubnormalF32Sig( sigA );
107        expA = normExpSig.exp;
108        sigA = normExpSig.sig;
109    }
110    if ( ! expB ) {
111        if ( ! sigB ) goto zeroProd;
112        normExpSig = softfloat_normSubnormalF32Sig( sigB );
113        expB = normExpSig.exp;
114        sigB = normExpSig.sig;
115    }
116    /*------------------------------------------------------------------------
117    *------------------------------------------------------------------------*/
118    expProd = expA + expB - 0x7E;
119    sigA = (sigA | 0x00800000)<<7;
120    sigB = (sigB | 0x00800000)<<7;
121    sigProd = (uint_fast64_t) sigA * sigB;
122    if ( sigProd < UINT64_C( 0x2000000000000000 ) ) {
123        --expProd;
124        sigProd <<= 1;
125    }
126    signZ = signProd;
127    if ( ! expC ) {
128        if ( ! sigC ) {
129            expZ = expProd - 1;
130            sigZ = softfloat_shortShiftRightJam64( sigProd, 31 );
131            goto roundPack;
132        }
133        normExpSig = softfloat_normSubnormalF32Sig( sigC );
134        expC = normExpSig.exp;
135        sigC = normExpSig.sig;
136    }
137    sigC = (sigC | 0x00800000)<<6;
138    /*------------------------------------------------------------------------
139    *------------------------------------------------------------------------*/
140    expDiff = expProd - expC;
141    if ( signProd == signC ) {
142        /*--------------------------------------------------------------------
143        *--------------------------------------------------------------------*/
144        if ( expDiff <= 0 ) {
145            expZ = expC;
146            sigZ = sigC + softfloat_shiftRightJam64( sigProd, 32 - expDiff );
147        } else {
148            expZ = expProd;
149            sig64Z =
150                sigProd
151                    + softfloat_shiftRightJam64(
152                          (uint_fast64_t) sigC<<32, expDiff );
153            sigZ = softfloat_shortShiftRightJam64( sig64Z, 32 );
154        }
155        if ( sigZ < 0x40000000 ) {
156            --expZ;
157            sigZ <<= 1;
158        }
159    } else {
160        /*--------------------------------------------------------------------
161        *--------------------------------------------------------------------*/
162        sig64C = (uint_fast64_t) sigC<<32;
163        if ( expDiff < 0 ) {
164            signZ = signC;
165            expZ = expC;
166            sig64Z = sig64C - softfloat_shiftRightJam64( sigProd, -expDiff );
167        } else if ( ! expDiff ) {
168            expZ = expProd;
169            sig64Z = sigProd - sig64C;
170            if ( ! sig64Z ) goto completeCancellation;
171            if ( sig64Z & UINT64_C( 0x8000000000000000 ) ) {
172                signZ = ! signZ;
173                sig64Z = -sig64Z;
174            }
175        } else {
176            expZ = expProd;
177            sig64Z = sigProd - softfloat_shiftRightJam64( sig64C, expDiff );
178        }
179        shiftDist = softfloat_countLeadingZeros64( sig64Z ) - 1;
180        expZ -= shiftDist;
181        shiftDist -= 32;
182        if ( shiftDist < 0 ) {
183            sigZ = softfloat_shortShiftRightJam64( sig64Z, -shiftDist );
184        } else {
185            sigZ = (uint_fast32_t) sig64Z<<shiftDist;
186        }
187    }
188 roundPack:
189    return softfloat_roundPackToF32( signZ, expZ, sigZ );
190    /*------------------------------------------------------------------------
191    *------------------------------------------------------------------------*/
192 propagateNaN_ABC:
193    uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
194    goto propagateNaN_ZC;
195    /*------------------------------------------------------------------------
196    *------------------------------------------------------------------------*/
197 infProdArg:
198    if ( magBits ) {
199        uiZ = packToF32UI( signProd, 0xFF, 0 );
200        if ( expC != 0xFF ) goto uiZ;
201        if ( sigC ) goto propagateNaN_ZC;
202        if ( signProd == signC ) goto uiZ;
203    }
204    softfloat_raiseFlags( softfloat_flag_invalid );
205    uiZ = defaultNaNF32UI;
206 propagateNaN_ZC:
207    uiZ = softfloat_propagateNaNF32UI( uiZ, uiC );
208    goto uiZ;
209    /*------------------------------------------------------------------------
210    *------------------------------------------------------------------------*/
211 zeroProd:
212    uiZ = uiC;
213    if ( ! (expC | sigC) && (signProd != signC) ) {
214 completeCancellation:
215        uiZ =
216            packToF32UI(
217                (softfloat_roundingMode == softfloat_round_min), 0, 0 );
218    }
219 uiZ:
220    uZ.ui = uiZ;
221    return uZ.f;
222
223}
224
225