aboutsummaryrefslogtreecommitdiff
path: root/softfloat/f32_mul.c
blob: d49c1ddadbc9e2e96c7b3f92e7a99c96af097d54 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89

#include <stdbool.h>
#include <stdint.h>
#include "platform.h"
#include "primitives.h"
#include "internals.h"
#include "specialize.h"
#include "softfloat.h"

float32_t f32_mul( float32_t a, float32_t b )
{
    union ui32_f32 uA;
    uint_fast32_t uiA;
    bool signA;
    int_fast16_t expA;
    uint_fast32_t sigA;
    union ui32_f32 uB;
    uint_fast32_t uiB;
    bool signB;
    int_fast16_t expB;
    uint_fast32_t sigB;
    bool signZ;
    uint_fast32_t magBits;
    struct exp16_sig32 normExpSig;
    int_fast16_t expZ;
    uint_fast32_t sigZ, uiZ;
    union ui32_f32 uZ;

    uA.f = a;
    uiA = uA.ui;
    signA = signF32UI( uiA );
    expA = expF32UI( uiA );
    sigA = fracF32UI( uiA );
    uB.f = b;
    uiB = uB.ui;
    signB = signF32UI( uiB );
    expB = expF32UI( uiB );
    sigB = fracF32UI( uiB );
    signZ = signA ^ signB;
    if ( expA == 0xFF ) {
        if ( sigA || ( ( expB == 0xFF ) && sigB ) ) goto propagateNaN;
        magBits = expB | sigB;
        goto infArg;
    }
    if ( expB == 0xFF ) {
        if ( sigB ) goto propagateNaN;
        magBits = expA | sigA;
        goto infArg;
    }
    if ( ! expA ) {
        if ( ! sigA ) goto zero;
        normExpSig = softfloat_normSubnormalF32Sig( sigA );
        expA = normExpSig.exp;
        sigA = normExpSig.sig;
    }
    if ( ! expB ) {
        if ( ! sigB ) goto zero;
        normExpSig = softfloat_normSubnormalF32Sig( sigB );
        expB = normExpSig.exp;
        sigB = normExpSig.sig;
    }
    expZ = expA + expB - 0x7F;
    sigA = ( sigA | 0x00800000 )<<7;
    sigB = ( sigB | 0x00800000 )<<8;
    sigZ = softfloat_shortShift64RightJam( (uint_fast64_t) sigA * sigB, 32 );
    if ( sigZ < 0x40000000 ) {
        --expZ;
        sigZ <<= 1;
    }
    return softfloat_roundPackToF32( signZ, expZ, sigZ );
 propagateNaN:
    uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
    goto uiZ;
 infArg:
    if ( ! magBits ) {
        softfloat_raiseFlags( softfloat_flag_invalid );
        uiZ = defaultNaNF32UI;
    } else {
        uiZ = packToF32UI( signZ, 0xFF, 0 );
    }
    goto uiZ;
 zero:
    uiZ = packToF32UI( signZ, 0, 0 );
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;

}