1
2 /*============================================================================
3
4 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
5 Package, Release 3e, by John R. Hauser.
6
7 Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
8 California. All rights reserved.
9
10 Redistribution and use in source and binary forms, with or without
11 modification, 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
24 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
25 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
27 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
28 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31 ON 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
33 SOFTWARE, 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
f16_mul(float16_t a,float16_t b)44 float16_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