1// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// mathutil.h: Math and bit manipulation functions.
16
17#ifndef LIBGLESV2_MATHUTIL_H_
18#define LIBGLESV2_MATHUTIL_H_
19
20#include "common/debug.h"
21#include "Common/Math.hpp"
22#include <limits>
23
24namespace es2
25{
26inline bool isPow2(int x)
27{
28 return (x & (x - 1)) == 0 && (x != 0);
29}
30
31inline int log2(int x)
32{
33 int r = 0;
34 while((x >> r) > 1) r++;
35 return r;
36}
37
38inline unsigned int ceilPow2(unsigned int x)
39{
40 if(x != 0) x--;
41 x |= x >> 1;
42 x |= x >> 2;
43 x |= x >> 4;
44 x |= x >> 8;
45 x |= x >> 16;
46 x++;
47
48 return x;
49}
50
51using sw::swap;
52using sw::clamp;
53using sw::clamp01;
54
55template<const int n>
56inline unsigned int unorm(float x)
57{
58 const unsigned int max = 0xFFFFFFFF >> (32 - n);
59
60 if(x > 1)
61 {
62 return max;
63 }
64 else if(x < 0)
65 {
66 return 0;
67 }
68 else
69 {
70 return (unsigned int)(max * x + 0.5f);
71 }
72}
73
74// Converts floating-point values to the nearest representable integer
75inline int convert_float_int(float x)
76{
77 // The largest positive integer value that is exactly representable in IEEE 754 binary32 is 0x7FFFFF80.
78 // The next floating-point value is 128 larger and thus needs clamping to 0x7FFFFFFF.
79 static_assert(std::numeric_limits<float>::is_iec559, "Unsupported floating-point format");
80
81 if(x > 0x7FFFFF80)
82 {
83 return 0x7FFFFFFF;
84 }
85
86 if(x < (signed)0x80000000)
87 {
88 return 0x80000000;
89 }
90
91 return static_cast<int>(roundf(x));
92}
93
94inline int convert_float_fixed(float x)
95{
96 return convert_float_int(static_cast<float>(0x7FFFFFFF) * x);
97}
98}
99
100#endif // LIBGLESV2_MATHUTIL_H_
101