1 // SPDX-License-Identifier: BSD-3-Clause
2 
3 /*============================================================================
4 
5 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
6 Package, Release 3a, by John R. Hauser.
7 
8 Copyright 2011, 2012, 2013, 2014 The Regents of the University of California.
9 All rights reserved.
10 
11 Redistribution and use in source and binary forms, with or without
12 modification, are permitted provided that the following conditions are met:
13 
14  1. Redistributions of source code must retain the above copyright notice,
15     this list of conditions, and the following disclaimer.
16 
17  2. Redistributions in binary form must reproduce the above copyright notice,
18     this list of conditions, and the following disclaimer in the documentation
19     and/or other materials provided with the distribution.
20 
21  3. Neither the name of the University nor the names of its contributors may
22     be used to endorse or promote products derived from this software without
23     specific prior written permission.
24 
25 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
26 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
27 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
28 DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
29 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
30 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
31 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
32 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 
36 =============================================================================*/
37 
38 #include <stdbool.h>
39 #include <stdint.h>
40 #include "platform.h"
41 #include "internals.h"
42 #include "specialize.h"
43 #include "softfloat.h"
44 
f32_mul(float32_t a,float32_t b)45 float32_t f32_mul( float32_t a, float32_t b )
46 {
47     union ui32_f32 uA;
48     uint_fast32_t uiA;
49     bool signA;
50     int_fast16_t expA;
51     uint_fast32_t sigA;
52     union ui32_f32 uB;
53     uint_fast32_t uiB;
54     bool signB;
55     int_fast16_t expB;
56     uint_fast32_t sigB;
57     bool signZ;
58     uint_fast32_t magBits;
59     struct exp16_sig32 normExpSig;
60     int_fast16_t expZ;
61     uint_fast32_t sigZ, uiZ;
62     union ui32_f32 uZ;
63 
64     uA.f = a;
65     uiA = uA.ui;
66     signA = signF32UI( uiA );
67     expA  = expF32UI( uiA );
68     sigA  = fracF32UI( uiA );
69     uB.f = b;
70     uiB = uB.ui;
71     signB = signF32UI( uiB );
72     expB  = expF32UI( uiB );
73     sigB  = fracF32UI( uiB );
74     signZ = signA ^ signB;
75     if ( expA == 0xFF ) {
76         if ( sigA || ((expB == 0xFF) && sigB) ) goto propagateNaN;
77         magBits = expB | sigB;
78         goto infArg;
79     }
80     if ( expB == 0xFF ) {
81         if ( sigB ) goto propagateNaN;
82         magBits = expA | sigA;
83         goto infArg;
84     }
85     if ( ! expA ) {
86         if ( ! sigA ) goto zero;
87         normExpSig = softfloat_normSubnormalF32Sig( sigA );
88         expA = normExpSig.exp;
89         sigA = normExpSig.sig;
90     }
91     if ( ! expB ) {
92         if ( ! sigB ) goto zero;
93         normExpSig = softfloat_normSubnormalF32Sig( sigB );
94         expB = normExpSig.exp;
95         sigB = normExpSig.sig;
96     }
97     expZ = expA + expB - 0x7F;
98     sigA = (sigA | 0x00800000)<<7;
99     sigB = (sigB | 0x00800000)<<8;
100     sigZ = softfloat_shortShiftRightJam64( (uint_fast64_t) sigA * sigB, 32 );
101     if ( sigZ < 0x40000000 ) {
102         --expZ;
103         sigZ <<= 1;
104     }
105     return softfloat_roundPackToF32( signZ, expZ, sigZ );
106  propagateNaN:
107     uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
108     goto uiZ;
109  infArg:
110     if ( ! magBits ) {
111         softfloat_raiseFlags( softfloat_flag_invalid );
112         uiZ = defaultNaNF32UI;
113     } else {
114         uiZ = packToF32UI( signZ, 0xFF, 0 );
115     }
116     goto uiZ;
117  zero:
118     uiZ = packToF32UI( signZ, 0, 0 );
119  uiZ:
120     uZ.ui = uiZ;
121     return uZ.f;
122 
123 }
124 
125