1 /*
2 * Copyright 2015 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 #include "dm_services.h"
26 #include "bw_fixed.h"
27
28
29 #define MAX_I64 \
30 (int64_t)((1ULL << 63) - 1)
31
32 #define MIN_I64 \
33 (-MAX_I64 - 1)
34
35 #define FRACTIONAL_PART_MASK \
36 ((1ULL << BW_FIXED_BITS_PER_FRACTIONAL_PART) - 1)
37
38 #define GET_FRACTIONAL_PART(x) \
39 (FRACTIONAL_PART_MASK & (x))
40
abs_i64(int64_t arg)41 static uint64_t abs_i64(int64_t arg)
42 {
43 if (arg >= 0)
44 return (uint64_t)(arg);
45 else
46 return (uint64_t)(-arg);
47 }
48
bw_int_to_fixed_nonconst(int64_t value)49 struct bw_fixed bw_int_to_fixed_nonconst(int64_t value)
50 {
51 struct bw_fixed res;
52 ASSERT(value < BW_FIXED_MAX_I32 && value > BW_FIXED_MIN_I32);
53 res.value = value << BW_FIXED_BITS_PER_FRACTIONAL_PART;
54 return res;
55 }
56
bw_frc_to_fixed(int64_t numerator,int64_t denominator)57 struct bw_fixed bw_frc_to_fixed(int64_t numerator, int64_t denominator)
58 {
59 struct bw_fixed res;
60 bool arg1_negative = numerator < 0;
61 bool arg2_negative = denominator < 0;
62 uint64_t arg1_value;
63 uint64_t arg2_value;
64 uint64_t remainder;
65
66 /* determine integer part */
67 uint64_t res_value;
68
69 ASSERT(denominator != 0);
70
71 arg1_value = abs_i64(numerator);
72 arg2_value = abs_i64(denominator);
73 res_value = div64_u64_rem(arg1_value, arg2_value, &remainder);
74
75 ASSERT(res_value <= BW_FIXED_MAX_I32);
76
77 /* determine fractional part */
78 {
79 uint32_t i = BW_FIXED_BITS_PER_FRACTIONAL_PART;
80
81 do
82 {
83 remainder <<= 1;
84
85 res_value <<= 1;
86
87 if (remainder >= arg2_value)
88 {
89 res_value |= 1;
90 remainder -= arg2_value;
91 }
92 } while (--i != 0);
93 }
94
95 /* round up LSB */
96 {
97 uint64_t summand = (remainder << 1) >= arg2_value;
98
99 ASSERT(res_value <= MAX_I64 - summand);
100
101 res_value += summand;
102 }
103
104 res.value = (int64_t)(res_value);
105
106 if (arg1_negative ^ arg2_negative)
107 res.value = -res.value;
108 return res;
109 }
110
bw_floor2(const struct bw_fixed arg,const struct bw_fixed significance)111 struct bw_fixed bw_floor2(
112 const struct bw_fixed arg,
113 const struct bw_fixed significance)
114 {
115 struct bw_fixed result;
116 int64_t multiplicand;
117
118 multiplicand = div64_s64(arg.value, abs_i64(significance.value));
119 result.value = abs_i64(significance.value) * multiplicand;
120 ASSERT(abs_i64(result.value) <= abs_i64(arg.value));
121 return result;
122 }
123
bw_ceil2(const struct bw_fixed arg,const struct bw_fixed significance)124 struct bw_fixed bw_ceil2(
125 const struct bw_fixed arg,
126 const struct bw_fixed significance)
127 {
128 struct bw_fixed result;
129 int64_t multiplicand;
130
131 multiplicand = div64_s64(arg.value, abs_i64(significance.value));
132 result.value = abs_i64(significance.value) * multiplicand;
133 if (abs_i64(result.value) < abs_i64(arg.value)) {
134 if (arg.value < 0)
135 result.value -= abs_i64(significance.value);
136 else
137 result.value += abs_i64(significance.value);
138 }
139 return result;
140 }
141
bw_mul(const struct bw_fixed arg1,const struct bw_fixed arg2)142 struct bw_fixed bw_mul(const struct bw_fixed arg1, const struct bw_fixed arg2)
143 {
144 struct bw_fixed res;
145
146 bool arg1_negative = arg1.value < 0;
147 bool arg2_negative = arg2.value < 0;
148
149 uint64_t arg1_value = abs_i64(arg1.value);
150 uint64_t arg2_value = abs_i64(arg2.value);
151
152 uint64_t arg1_int = BW_FIXED_GET_INTEGER_PART(arg1_value);
153 uint64_t arg2_int = BW_FIXED_GET_INTEGER_PART(arg2_value);
154
155 uint64_t arg1_fra = GET_FRACTIONAL_PART(arg1_value);
156 uint64_t arg2_fra = GET_FRACTIONAL_PART(arg2_value);
157
158 uint64_t tmp;
159
160 res.value = arg1_int * arg2_int;
161
162 ASSERT(res.value <= BW_FIXED_MAX_I32);
163
164 res.value <<= BW_FIXED_BITS_PER_FRACTIONAL_PART;
165
166 tmp = arg1_int * arg2_fra;
167
168 ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
169
170 res.value += tmp;
171
172 tmp = arg2_int * arg1_fra;
173
174 ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
175
176 res.value += tmp;
177
178 tmp = arg1_fra * arg2_fra;
179
180 tmp = (tmp >> BW_FIXED_BITS_PER_FRACTIONAL_PART) +
181 (tmp >= (uint64_t)(bw_frc_to_fixed(1, 2).value));
182
183 ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
184
185 res.value += tmp;
186
187 if (arg1_negative ^ arg2_negative)
188 res.value = -res.value;
189 return res;
190 }
191
192