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 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
44float16_t f16_mul( float16_t a, float16_t b )
45{
46    union ui16_f16 uA;
47    uint_fast16_t uiA;
48    bool signA;
49    int_fast8_t expA;
50    uint_fast16_t sigA;
51    union ui16_f16 uB;
52    uint_fast16_t uiB;
53    bool signB;
54    int_fast8_t expB;
55    uint_fast16_t sigB;
56    bool signZ;
57    uint_fast16_t magBits;
58    struct exp8_sig16 normExpSig;
59    int_fast8_t expZ;
60    uint_fast32_t sig32Z;
61    uint_fast16_t sigZ, uiZ;
62    union ui16_f16 uZ;
63
64    /*------------------------------------------------------------------------
65    *------------------------------------------------------------------------*/
66    uA.f = a;
67    uiA = uA.ui;
68    signA = signF16UI( uiA );
69    expA  = expF16UI( uiA );
70    sigA  = fracF16UI( uiA );
71    uB.f = b;
72    uiB = uB.ui;
73    signB = signF16UI( uiB );
74    expB  = expF16UI( uiB );
75    sigB  = fracF16UI( uiB );
76    signZ = signA ^ signB;
77    /*------------------------------------------------------------------------
78    *------------------------------------------------------------------------*/
79    if ( expA == 0x1F ) {
80        if ( sigA || ((expB == 0x1F) && sigB) ) goto propagateNaN;
81        magBits = expB | sigB;
82        goto infArg;
83    }
84    if ( expB == 0x1F ) {
85        if ( sigB ) goto propagateNaN;
86        magBits = expA | sigA;
87        goto infArg;
88    }
89    /*------------------------------------------------------------------------
90    *------------------------------------------------------------------------*/
91    if ( ! expA ) {
92        if ( ! sigA ) goto zero;
93        normExpSig = softfloat_normSubnormalF16Sig( sigA );
94        expA = normExpSig.exp;
95        sigA = normExpSig.sig;
96    }
97    if ( ! expB ) {
98        if ( ! sigB ) goto zero;
99        normExpSig = softfloat_normSubnormalF16Sig( sigB );
100        expB = normExpSig.exp;
101        sigB = normExpSig.sig;
102    }
103    /*------------------------------------------------------------------------
104    *------------------------------------------------------------------------*/
105    expZ = expA + expB - 0xF;
106    sigA = (sigA | 0x0400)<<4;
107    sigB = (sigB | 0x0400)<<5;
108    sig32Z = (uint_fast32_t) sigA * sigB;
109    sigZ = sig32Z>>16;
110    if ( sig32Z & 0xFFFF ) sigZ |= 1;
111    if ( sigZ < 0x4000 ) {
112        --expZ;
113        sigZ <<= 1;
114    }
115    return softfloat_roundPackToF16( signZ, expZ, sigZ );
116    /*------------------------------------------------------------------------
117    *------------------------------------------------------------------------*/
118 propagateNaN:
119    uiZ = softfloat_propagateNaNF16UI( uiA, uiB );
120    goto uiZ;
121    /*------------------------------------------------------------------------
122    *------------------------------------------------------------------------*/
123 infArg:
124    if ( ! magBits ) {
125        softfloat_raiseFlags( softfloat_flag_invalid );
126        uiZ = defaultNaNF16UI;
127    } else {
128        uiZ = packToF16UI( signZ, 0x1F, 0 );
129    }
130    goto uiZ;
131    /*------------------------------------------------------------------------
132    *------------------------------------------------------------------------*/
133 zero:
134    uiZ = packToF16UI( signZ, 0, 0 );
135 uiZ:
136    uZ.ui = uiZ;
137    return uZ.f;
138
139}
140
141