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
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
# md5x16
AVX-512 accelerated 16-lane [MD5](https://en.wikipedia.org/wiki/MD5) in `avo`.
Inspired by [`minio/md5-simd`](https://github.com/minio/md5-simd) and
[`igneous-systems/md5vec`](https://github.com/igneous-systems/md5vec).
Note that the focus of this example is the core assembly `block` function. The
`Sum` function can only handle parallel hashes of exactly the same length. In
practice you'd likely need hash server functionality provided by
[`md5-simd`](https://github.com/minio/md5-simd) to multiplex independent hashes
of different lengths into the 16 SIMD lanes.
[embedmd]:# (asm.go /func main/ /^}/)
```go
func main() {
// Define round constants data section.
//
// These may be computed as the integer part of abs(sin(i+1))*2^32.
T := GLOBL("consts", RODATA|NOPTR)
for i := 0; i < 64; i++ {
k := uint32(math.Floor(math.Ldexp(math.Abs(math.Sin(float64(i+1))), 32)))
DATA(4*i, U32(k))
}
// MD5 16-lane block function.
TEXT("block", 0, "func(h *[4][16]uint32, base uintptr, offsets *[16]uint32, mask uint16)")
Doc(
"block MD5 hashes 16 messages into the running hash states h. Messages are",
"at the given offsets from the base pointer. The 16-bit mask specifies",
"which lanes are active: when bit i is not set loads will be disabled and",
"the value of the resulting hash is undefined.",
)
h := Mem{Base: Load(Param("h"), GP64())}
base := Mem{Base: Load(Param("base"), GP64())}
offsetsptr := Mem{Base: Load(Param("offsets"), GP64())}
mask := Load(Param("mask"), K())
Comment("Load offsets.")
offsets := ZMM()
VMOVUPD(offsetsptr, offsets)
Comment("Load initial hash.")
hash := [4]Register{ZMM(), ZMM(), ZMM(), ZMM()}
for i, r := range hash {
VMOVUPD(h.Offset(64*i), r)
}
Comment("Initialize registers.")
a, b, c, d := ZMM(), ZMM(), ZMM(), ZMM()
for i, r := range []Register{a, b, c, d} {
VMOVUPD(hash[i], r)
}
// Allocate message registers.
m := make([]Register, 16)
for i := range m {
m[i] = ZMM()
}
// Generate round updates.
//
// Each 16-round block is parameterized based on the btiwise function,
// message indexes and shift amounts. Constants B, C, D are helpers in
// computing the logic table required by VPTERNLOGD.
const (
B = uint8(0b10101010)
C = uint8(0b11001100)
D = uint8(0b11110000)
)
quarter := []struct {
F uint8 // ternary logic table
i func(int) int // message index at round r
s []int // shift amounts
}{
{
F: (B & C) | (^B & D),
i: func(r int) int { return r % 16 },
s: []int{7, 12, 17, 22},
},
{
F: (D & B) | (^D & C),
i: func(r int) int { return (5*r + 1) % 16 },
s: []int{5, 9, 14, 20},
},
{
F: B ^ C ^ D,
i: func(r int) int { return (3*r + 5) % 16 },
s: []int{4, 11, 16, 23},
},
{
F: C ^ (B | ^D),
i: func(r int) int { return (7 * r) % 16 },
s: []int{6, 10, 15, 21},
},
}
for r := 0; r < 64; r++ {
Commentf("Round %d.", r)
q := quarter[r/16]
// Load message words.
if r < 16 {
k := K()
KMOVW(mask, k)
VPGATHERDD(base.Offset(4*r).Idx(offsets, 1), k, m[r])
}
VPADDD(m[q.i(r)], a, a)
VPADDD_BCST(T.Offset(4*r), a, a)
f := ZMM()
VMOVUPD(d, f)
VPTERNLOGD(U8(q.F), b, c, f)
VPADDD(f, a, a)
VPROLD(U8(q.s[r%4]), a, a)
VPADDD(b, a, a)
a, b, c, d = d, a, b, c
}
Comment("Final add.")
for i, r := range []Register{a, b, c, d} {
VPADDD(r, hash[i], hash[i])
}
Comment("Store results back.")
for i, r := range hash {
VMOVUPD(r, h.Offset(64*i))
}
VZEROUPPER()
RET()
Generate()
}
```
|
