File size: 3,516 Bytes
be903e2
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
136
// Tencent is pleased to support the open source community by making ncnn available.
//
// Copyright (C) 2021 THL A29 Limited, a Tencent company. All rights reserved.
//
// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// https://opensource.org/licenses/BSD-3-Clause
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#include "utils.h"

namespace pnnx {

const torch::jit::Node* find_node_by_kind(const std::shared_ptr<torch::jit::Graph>& graph, const std::string& kind)
{
    for (const auto& n : graph->nodes())
    {
        if (n->kind().toDisplayString() == kind)
            return n;
    }

    return 0;
}

unsigned short float32_to_float16(float value)
{
    // 1 : 8 : 23
    union
    {
        unsigned int u;
        float f;
    } tmp;

    tmp.f = value;

    // 1 : 8 : 23
    unsigned short sign = (tmp.u & 0x80000000) >> 31;
    unsigned short exponent = (tmp.u & 0x7F800000) >> 23;
    unsigned int significand = tmp.u & 0x7FFFFF;

    //     NCNN_LOGE("%d %d %d", sign, exponent, significand);

    // 1 : 5 : 10
    unsigned short fp16;
    if (exponent == 0)
    {
        // zero or denormal, always underflow
        fp16 = (sign << 15) | (0x00 << 10) | 0x00;
    }
    else if (exponent == 0xFF)
    {
        // infinity or NaN
        fp16 = (sign << 15) | (0x1F << 10) | (significand ? 0x200 : 0x00);
    }
    else
    {
        // normalized
        short newexp = exponent + (-127 + 15);
        if (newexp >= 31)
        {
            // overflow, return infinity
            fp16 = (sign << 15) | (0x1F << 10) | 0x00;
        }
        else if (newexp <= 0)
        {
            // Some normal fp32 cannot be expressed as normal fp16
            fp16 = (sign << 15) | (0x00 << 10) | 0x00;
        }
        else
        {
            // normal fp16
            fp16 = (sign << 15) | (newexp << 10) | (significand >> 13);
        }
    }

    return fp16;
}

float float16_to_float32(unsigned short value)
{
    // 1 : 5 : 10
    unsigned short sign = (value & 0x8000) >> 15;
    unsigned short exponent = (value & 0x7c00) >> 10;
    unsigned short significand = value & 0x03FF;

    //     NCNN_LOGE("%d %d %d", sign, exponent, significand);

    // 1 : 8 : 23
    union
    {
        unsigned int u;
        float f;
    } tmp;
    if (exponent == 0)
    {
        if (significand == 0)
        {
            // zero
            tmp.u = (sign << 31);
        }
        else
        {
            // denormal
            exponent = 0;
            // find non-zero bit
            while ((significand & 0x200) == 0)
            {
                significand <<= 1;
                exponent++;
            }
            significand <<= 1;
            significand &= 0x3FF;
            tmp.u = (sign << 31) | ((-exponent + (-15 + 127)) << 23) | (significand << 13);
        }
    }
    else if (exponent == 0x1F)
    {
        // infinity or NaN
        tmp.u = (sign << 31) | (0xFF << 23) | (significand << 13);
    }
    else
    {
        // normalized
        tmp.u = (sign << 31) | ((exponent + (-15 + 127)) << 23) | (significand << 13);
    }

    return tmp.f;
}

} // namespace pnnx