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 #include "dm_services.h"
26 #include "custom_float.h"
27
28
build_custom_float(struct fixed31_32 value,const struct custom_float_format * format,bool * negative,uint32_t * mantissa,uint32_t * exponenta)29 static bool build_custom_float(
30 struct fixed31_32 value,
31 const struct custom_float_format *format,
32 bool *negative,
33 uint32_t *mantissa,
34 uint32_t *exponenta)
35 {
36 uint32_t exp_offset = (1 << (format->exponenta_bits - 1)) - 1;
37
38 const struct fixed31_32 mantissa_constant_plus_max_fraction =
39 dc_fixpt_from_fraction(
40 (1LL << (format->mantissa_bits + 1)) - 1,
41 1LL << format->mantissa_bits);
42
43 struct fixed31_32 mantiss;
44
45 if (dc_fixpt_eq(
46 value,
47 dc_fixpt_zero)) {
48 *negative = false;
49 *mantissa = 0;
50 *exponenta = 0;
51 return true;
52 }
53
54 if (dc_fixpt_lt(
55 value,
56 dc_fixpt_zero)) {
57 *negative = format->sign;
58 value = dc_fixpt_neg(value);
59 } else {
60 *negative = false;
61 }
62
63 if (dc_fixpt_lt(
64 value,
65 dc_fixpt_one)) {
66 uint32_t i = 1;
67
68 do {
69 value = dc_fixpt_shl(value, 1);
70 ++i;
71 } while (dc_fixpt_lt(
72 value,
73 dc_fixpt_one));
74
75 --i;
76
77 if (exp_offset <= i) {
78 *mantissa = 0;
79 *exponenta = 0;
80 return true;
81 }
82
83 *exponenta = exp_offset - i;
84 } else if (dc_fixpt_le(
85 mantissa_constant_plus_max_fraction,
86 value)) {
87 uint32_t i = 1;
88
89 do {
90 value = dc_fixpt_shr(value, 1);
91 ++i;
92 } while (dc_fixpt_lt(
93 mantissa_constant_plus_max_fraction,
94 value));
95
96 *exponenta = exp_offset + i - 1;
97 } else {
98 *exponenta = exp_offset;
99 }
100
101 mantiss = dc_fixpt_sub(
102 value,
103 dc_fixpt_one);
104
105 if (dc_fixpt_lt(
106 mantiss,
107 dc_fixpt_zero) ||
108 dc_fixpt_lt(
109 dc_fixpt_one,
110 mantiss))
111 mantiss = dc_fixpt_zero;
112 else
113 mantiss = dc_fixpt_shl(
114 mantiss,
115 format->mantissa_bits);
116
117 *mantissa = dc_fixpt_floor(mantiss);
118
119 return true;
120 }
121
setup_custom_float(const struct custom_float_format * format,bool negative,uint32_t mantissa,uint32_t exponenta,uint32_t * result)122 static bool setup_custom_float(
123 const struct custom_float_format *format,
124 bool negative,
125 uint32_t mantissa,
126 uint32_t exponenta,
127 uint32_t *result)
128 {
129 uint32_t i = 0;
130 uint32_t j = 0;
131
132 uint32_t value = 0;
133
134 /* verification code:
135 * once calculation is ok we can remove it
136 */
137
138 const uint32_t mantissa_mask =
139 (1 << (format->mantissa_bits + 1)) - 1;
140
141 const uint32_t exponenta_mask =
142 (1 << (format->exponenta_bits + 1)) - 1;
143
144 if (mantissa & ~mantissa_mask) {
145 BREAK_TO_DEBUGGER();
146 mantissa = mantissa_mask;
147 }
148
149 if (exponenta & ~exponenta_mask) {
150 BREAK_TO_DEBUGGER();
151 exponenta = exponenta_mask;
152 }
153
154 /* end of verification code */
155
156 while (i < format->mantissa_bits) {
157 uint32_t mask = 1 << i;
158
159 if (mantissa & mask)
160 value |= mask;
161
162 ++i;
163 }
164
165 while (j < format->exponenta_bits) {
166 uint32_t mask = 1 << j;
167
168 if (exponenta & mask)
169 value |= mask << i;
170
171 ++j;
172 }
173
174 if (negative && format->sign)
175 value |= 1 << (i + j);
176
177 *result = value;
178
179 return true;
180 }
181
convert_to_custom_float_format(struct fixed31_32 value,const struct custom_float_format * format,uint32_t * result)182 bool convert_to_custom_float_format(
183 struct fixed31_32 value,
184 const struct custom_float_format *format,
185 uint32_t *result)
186 {
187 uint32_t mantissa;
188 uint32_t exponenta;
189 bool negative;
190
191 return build_custom_float(
192 value, format, &negative, &mantissa, &exponenta) &&
193 setup_custom_float(
194 format, negative, mantissa, exponenta, result);
195 }
196
197
198