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fp16_emu.cuh
1 /**
2 * Copyright (c) Facebook, Inc. and its affiliates.
3 *
4 * This source code is licensed under the MIT license found in the
5 * LICENSE file in the root directory of this source tree.
6 */
7
8 // from Nvidia cuDNN library samples; modified to compile within faiss
9
10 #pragma once
11
12 namespace faiss { namespace gpu {
13
14 /*
15 * Copyright 1993-2014 NVIDIA Corporation. All rights reserved.
16 *
17 * NOTICE TO LICENSEE:
18 *
19 * This source code and/or documentation ("Licensed Deliverables") are
20 * subject to NVIDIA intellectual property rights under U.S. and
21 * international Copyright laws.
22 *
23 * These Licensed Deliverables contained herein is PROPRIETARY and
24 * CONFIDENTIAL to NVIDIA and is being provided under the terms and
25 * conditions of a form of NVIDIA software license agreement by and
26 * between NVIDIA and Licensee ("License Agreement") or electronically
27 * accepted by Licensee. Notwithstanding any terms or conditions to
28 * the contrary in the License Agreement, reproduction or disclosure
29 * of the Licensed Deliverables to any third party without the express
30 * written consent of NVIDIA is prohibited.
31 *
32 * NOTWITHSTANDING ANY TERMS OR CONDITIONS TO THE CONTRARY IN THE
33 * LICENSE AGREEMENT, NVIDIA MAKES NO REPRESENTATION ABOUT THE
34 * SUITABILITY OF THESE LICENSED DELIVERABLES FOR ANY PURPOSE. IT IS
35 * PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY OF ANY KIND.
36 * NVIDIA DISCLAIMS ALL WARRANTIES WITH REGARD TO THESE LICENSED
37 * DELIVERABLES, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
38 * NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE.
39 * NOTWITHSTANDING ANY TERMS OR CONDITIONS TO THE CONTRARY IN THE
40 * LICENSE AGREEMENT, IN NO EVENT SHALL NVIDIA BE LIABLE FOR ANY
41 * SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, OR ANY
42 * DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
43 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
44 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
45 * OF THESE LICENSED DELIVERABLES.
46 *
47 * U.S. Government End Users. These Licensed Deliverables are a
48 * "commercial item" as that term is defined at 48 C.F.R. 2.101 (OCT
49 * 1995), consisting of "commercial computer software" and "commercial
50 * computer software documentation" as such terms are used in 48
51 * C.F.R. 12.212 (SEPT 1995) and is provided to the U.S. Government
52 * only as a commercial end item. Consistent with 48 C.F.R.12.212 and
53 * 48 C.F.R. 227.7202-1 through 227.7202-4 (JUNE 1995), all
54 * U.S. Government End Users acquire the Licensed Deliverables with
55 * only those rights set forth herein.
56 *
57 * Any use of the Licensed Deliverables in individual and commercial
58 * software must include, in the user documentation and internal
59 * comments to the code, the above Disclaimer and U.S. Government End
60 * Users Notice.
61 */
62
63 // Conversion from/to 16-bit floating point (half-precision).
64
65 #define HLF_EPSILON 4.887581E-04
66
67 typedef struct __align__(2) {
68 unsigned short x;
69 } half1;
70
71 half1 cpu_float2half_rn(float f);
72
73 float cpu_half2float(half1 h);
74
75 static __inline__ __device__ __host__ half1 habs(half1 h)
76 {
77 h.x &= 0x7fffU;
78 return h;
79 }
80
81 static __inline__ __device__ __host__ half1 hneg(half1 h)
82 {
83 h.x ^= 0x8000U;
84 return h;
85 }
86
87 static __inline__ __device__ __host__ int ishnan(half1 h)
88 {
89 // When input is NaN, exponent is all ones and mantissa is non-zero.
90 return (h.x & 0x7c00U) == 0x7c00U && (h.x & 0x03ffU) != 0;
91 }
92
93 static __inline__ __device__ __host__ int ishinf(half1 h)
94 {
95 // When input is +/- inf, exponent is all ones and mantissa is zero.
96 return (h.x & 0x7c00U) == 0x7c00U && (h.x & 0x03ffU) == 0;
97 }
98
99 static __inline__ __device__ __host__ int ishequ(half1 x, half1 y)
100 {
101 return ishnan(x) == 0 && ishnan(y) == 0 && x.x == y.x;
102 }
103
104 static __inline__ __device__ __host__ half1 hzero()
105 {
106 half1 ret;
107 ret.x = 0x0000U;
108 return ret;
109 }
110
111 static __inline__ __device__ __host__ half1 hone()
112 {
113 half1 ret;
114 ret.x = 0x3c00U;
115 return ret;
116 }
117
118 } } // namespace