DSP Memory Region

Some of this is known to be incorrect. I'll correct this in a few months after a bit more RE work. Merry (talk) 21:10, 28 January 2016 (CET)

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The DSP communicates with userland through memory locations 0x1ff40000-0x1ff77fff. Within this region are two areas of structures that are exact duplicates of each other. The DSP alternates between the use of these two areas (much like a double-buffer). Each area has 15 structures within it. The location of these structures can be obtained by reading channel 2 of the DSP pipe.

The mixer has 24 channels, each of which are individually configurable.

Structure Number	DSP memory address	Size	Description
5	0x8400	0x20	Status (?)
9	0x8410	0x260	Debug (?)
6	0x8540	0x280	Loopback Samples (PCM16)
2	0x8680	0x120	Channel Status (x24)
8	0x9710	0x1A40	?
4	0x9430	0xC4	Main Configuration
7	0x9492	0x1400	?
1	0x9e92	0x1200	Channel Config (x24)
3	0x9430	0x300	GC-ADPCM Coefficients (x24)
10	0xa912	0x200
11	0xaa12	0x180
12	0xaad2	0x300
13	0xac52	0x14
14	0xac5c	0x2476	-
0	0xbfff	0x2	Frame Counter

Channel Config

A 192 byte long structure. There are 24 of them.

Offset	Type	Description
0	u32	Dirty flags
4	70 bytes	TODO
74	u16	Bitmap of which buffers in queue are dirty
76	Buffer[4]	Buffer queue
156	u32	-
160	u16	Is Active
162	u16	Sync Count
164	8	TODO
172	u32	Physical address of current buffer
176	u32	Number of samples in current buffer
180	u16	bits[0:1]: 1 = mono, 2 = stereo; bits[2:3]: buffer format
182	u16	ADPCM predictor
184	s16	ADPCM yn1
186	s16	ADPCM yn2
188	u16	bit[0]: Has ADPCM data?; bit[1]: Is looping?
190	u16	Buffer Id of this current buffer

Buffer

Offset	Type	Description
0	u32	Physical Address
4	u32	Sample Count
8	u16	ADPCM P/S
10	s16[2]	ADPCM yn[1,2]
14	u8	Has ADPCM?
15	u8	Looping?
16	u16	Buffer Id
18	u16	-

Dirty Bits

Bit	What Changed
3	ADPCM Coefficients
5	Embedded buffer
13	Is Active
18	Interpolation Type
19	Rate
20	Buffer Queue
22	Embedded buffer
23	IRR Filter Type
25	Sync Count
26-28	Mix
30	First time init
31	Embedded Buffer