1/*
2 * Copyright 2017 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * Authors: AMD
23 *
24 */
25
26#include "os_types.h"
27#include "dcn_calc_math.h"
28
29#define isNaN(number) ((number) != (number))
30
31/*
32 * NOTE:
33 * This file is gcc-parseable HW gospel, coming straight from HW engineers.
34 *
35 * It doesn't adhere to Linux kernel style and sometimes will do things in odd
36 * ways. Unless there is something clearly wrong with it the code should
37 * remain as-is as it provides us with a guarantee from HW that it is correct.
38 */
39
40float dcn_bw_mod(const float arg1, const float arg2)
41{
42 if (isNaN(arg1))
43 return arg2;
44 if (isNaN(arg2))
45 return arg1;
46 return arg1 - arg1 * ((int) (arg1 / arg2));
47}
48
49float dcn_bw_min2(const float arg1, const float arg2)
50{
51 if (isNaN(arg1))
52 return arg2;
53 if (isNaN(arg2))
54 return arg1;
55 return arg1 < arg2 ? arg1 : arg2;
56}
57
58unsigned int dcn_bw_max(const unsigned int arg1, const unsigned int arg2)
59{
60 return arg1 > arg2 ? arg1 : arg2;
61}
62float dcn_bw_max2(const float arg1, const float arg2)
63{
64 if (isNaN(arg1))
65 return arg2;
66 if (isNaN(arg2))
67 return arg1;
68 return arg1 > arg2 ? arg1 : arg2;
69}
70
71float dcn_bw_floor2(const float arg, const float significance)
72{
73 ASSERT(significance != 0);
74
75 return ((int) (arg / significance)) * significance;
76}
77float dcn_bw_floor(const float arg)
78{
79 return ((int) (arg));
80}
81
82float dcn_bw_ceil(const float arg)
83{
84 return (int) (arg + 0.99999);
85}
86
87float dcn_bw_ceil2(const float arg, const float significance)
88{
89 ASSERT(significance != 0);
90
91 return ((int) (arg / significance + 0.99999)) * significance;
92}
93
94float dcn_bw_max3(float v1, float v2, float v3)
95{
96 return v3 > dcn_bw_max2(arg1: v1, arg2: v2) ? v3 : dcn_bw_max2(arg1: v1, arg2: v2);
97}
98
99float dcn_bw_max5(float v1, float v2, float v3, float v4, float v5)
100{
101 return dcn_bw_max3(v1, v2, v3) > dcn_bw_max2(arg1: v4, arg2: v5) ? dcn_bw_max3(v1, v2, v3) : dcn_bw_max2(arg1: v4, arg2: v5);
102}
103
104float dcn_bw_pow(float a, float exp)
105{
106 float temp;
107 /*ASSERT(exp == (int)exp);*/
108 if ((int)exp == 0)
109 return 1;
110 temp = dcn_bw_pow(a, exp: (int)(exp / 2));
111 if (((int)exp % 2) == 0) {
112 return temp * temp;
113 } else {
114 if ((int)exp > 0)
115 return a * temp * temp;
116 else
117 return (temp * temp) / a;
118 }
119}
120
121double dcn_bw_fabs(double a)
122{
123 if (a > 0)
124 return (a);
125 else
126 return (-a);
127}
128
129
130float dcn_bw_log(float a, float b)
131{
132 int * const exp_ptr = (int *)(&a);
133 int x = *exp_ptr;
134 const int log_2 = ((x >> 23) & 255) - 128;
135 x &= ~(255 << 23);
136 x += 127 << 23;
137 *exp_ptr = x;
138
139 a = ((-1.0f / 3) * a + 2) * a - 2.0f / 3;
140
141 if (b > 2.00001 || b < 1.99999)
142 return (a + log_2) / dcn_bw_log(a: b, b: 2);
143 else
144 return (a + log_2);
145}
146

source code of linux/drivers/gpu/drm/amd/display/dc/dml/calcs/dcn_calc_math.c