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