aboutsummaryrefslogtreecommitdiff
path: root/softfloat/s_addMagsF64.c
blob: d2a568604e5649a410f21cdb89a1b98c06f227cd (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
// See LICENSE.SoftFloat for license details.


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

float64_t
 softfloat_addMagsF64( uint_fast64_t uiA, uint_fast64_t uiB, bool signZ )
{
    int_fast16_t expA;
    uint_fast64_t sigA;
    int_fast16_t expB;
    uint_fast64_t sigB;
    int_fast16_t expDiff;
    uint_fast64_t uiZ;
    int_fast16_t expZ;
    uint_fast64_t sigZ;
    union ui64_f64 uZ;

    expA = expF64UI( uiA );
    sigA = fracF64UI( uiA );
    expB = expF64UI( uiB );
    sigB = fracF64UI( uiB );
    expDiff = expA - expB;
    sigA <<= 9;
    sigB <<= 9;
    if ( ! expDiff ) {
        if ( expA == 0x7FF ) {
            if ( sigA | sigB ) goto propagateNaN;
            uiZ = uiA;
            goto uiZ;
        }
        if ( ! expA ) {
            uiZ =
                packToF64UI(
                    signZ, 0, ( uiA + uiB ) & UINT64_C( 0x7FFFFFFFFFFFFFFF ) );
            goto uiZ;
        }
        expZ = expA;
        sigZ = UINT64_C( 0x4000000000000000 ) + sigA + sigB;
    } else {
        if ( expDiff < 0 ) {
            if ( expB == 0x7FF ) {
                if ( sigB ) goto propagateNaN;
                uiZ = packToF64UI( signZ, 0x7FF, 0 );
                goto uiZ;
            }
            expZ = expB;
            sigA += expA ? UINT64_C( 0x2000000000000000 ) : sigA;
            sigA = softfloat_shift64RightJam( sigA, - expDiff );
        } else {
            if ( expA == 0x7FF ) {
                if ( sigA ) goto propagateNaN;
                uiZ = uiA;
                goto uiZ;
            }
            expZ = expA;
            sigB += expB ? UINT64_C( 0x2000000000000000 ) : sigB;
            sigB = softfloat_shift64RightJam( sigB, expDiff );
        }
        sigZ = UINT64_C( 0x2000000000000000 ) + sigA + sigB;
        if ( sigZ < UINT64_C( 0x4000000000000000 ) ) {
            --expZ;
            sigZ <<= 1;
        }
    }
    return softfloat_roundPackToF64( signZ, expZ, sigZ );
 propagateNaN:
    uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;

}