aboutsummaryrefslogtreecommitdiff
path: root/src/DMA_Timings.cpp
blob: cea32820b15952e8c5525c93afe9bfded2cfbbf7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
    Copyright 2016-2023 melonDS team

    This file is part of melonDS.

    melonDS is free software: you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with melonDS. If not, see http://www.gnu.org/licenses/.
*/

#include "DMA_Timings.h"
#include "types.h"

namespace DMATiming
{

// DMA timing tables
//
// DMA timings on the DS are normally straightforward, except in one case: when
// main RAM is involved.
// Main RAM to main RAM is the easy case: 16c/unit in 16bit mode, 18c/unit in 32bit
// mode.
// It gets more complicated when transferring from main RAM to somewhere else, or
// vice versa: main RAM supports burst accesses, but the rules dictating how long
// bursts can be are weird and inconsistent. Main RAM also supports parallel
// memory operations, to some extent.
// I haven't figured out the full logic behind it, let alone how to emulate it
// efficiently, so for now we will use these tables.
// A zero denotes the end of a burst pattern.
//
// Note: burst patterns only apply when the main RAM address is incrementing.
// A fixed or decrementing address results in nonsequential accesses.
//
// Note about GBA slot/wifi timings: these take into account the sequential timing
// setting. Timings are such that the nonseq setting only matters for the first
// access, and minor edge cases (like the last of a 0x20000-byte block).

extern const std::array<u8, 256> MRAMDummy = {0};

extern const std::array<u8, 256> MRAMRead16Bursts[] =
{
    // main RAM to regular 16bit or 32bit bus (similar)
    {7, 3, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2,
     7, 3, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2,
     7, 3,
     0},
    // main RAM to GBA/wifi, seq=4
    {8, 6, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5,
     0},
    // main RAM to GBA/wifi, seq=6
    {10, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7,
     12, 8,
     0},
};

extern const std::array<u8, 256> MRAMRead32Bursts[] =
{
    // main RAM to regular 16bit bus
    {9, 4, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 9,
     0},
    // main RAM to regular 32bit bus
    {9, 3, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2,
     0},
    // main RAM to GBA/wifi, seq=4
    {14, 10, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9,
     13, 10, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9,
     13, 10, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9,
     13, 10, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9,
     13, 10, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
     9, 9, 9, 9, 9, 9, 9,
     13,
     0},
    // main RAM to GBA/wifi, seq=6
    {18, 14, 13, 13, 13, 13, 13, 13, 13, 13,
     13, 13, 13, 13, 13, 13, 13, 13, 13,
     17, 14, 13, 13, 13, 13, 13, 13, 13, 13,
     13, 13, 13, 13, 13, 13, 13, 13, 13,
     17, 14, 13, 13, 13, 13, 13, 13, 13, 13,
     13, 13, 13, 13, 13, 13, 13, 13, 13,
     17, 14, 13, 13, 13, 13, 13, 13, 13, 13,
     13, 13, 13, 13, 13, 13, 13, 13, 13,
     17, 14, 13, 13, 13, 13, 13, 13, 13, 13,
     13, 13, 13, 13, 13, 13, 13, 13, 13,
     17,
     0},
};

extern const std::array<u8, 256> MRAMWrite16Bursts[] =
{
    // regular 16bit or 32bit bus to main RAM (similar)
    {8, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
     0},
    // GBA/wifi to main RAM, seq=4
    {10, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
     5, 5, 5, 5, 5, 5, 5, 5,
     0},
    // GBA/wifi to main RAM, seq=6
    {9, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 7, 7, 7,
     0},
};

extern const std::array<u8, 256> MRAMWrite32Bursts[4] =
{
    // regular 16bit bus to main RAM
    {9, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
     0},
    // regular 32bit bus to main RAM
    {9, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
     0},
    // GBA/wifi to main RAM, seq=4
    {15, 10, 10, 10, 10, 10, 10, 10, 10, 10,
     10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
     10, 10, 10, 10,
     0},
    // GBA/wifi to main RAM, seq=6
    {16, 14, 14, 14, 14, 14, 14, 14, 14, 14,
     14, 14, 14, 14, 14, 14, 14, 14,
     0},
};

}