CSND Registers

From 3dbrew
Revision as of 05:24, 20 April 2019 by Wwylele (talk | contribs) (0x1EC03000: No, these are not DSP registers, which are located at 1ED03000 (100000 bytes off). RE of CSND command 0x200 also shows that this region has different layout than DSP registers. DSP reigsters are all 2-bytes, while command 0x200 writes 1/4)
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0x1EC03000

?

0x1EC03400

The channel registers are based at 0x1EC03400(process virtual address). There's 0x20-bytes total for each channel slot, thus the base-address for a channel's slot is determined with: 0x1EC03400 + (channel_index*0x20). The below offsets are relative to these channel register slots.

Relative offset Size Description
0x0 2 REG_CSNDCHANX_CNT. For Type0 Cmd 0xE, CSND module basically writes this value here: u16 (cmdword[2] & 0xFFFF).
0x2 2 For Type0 Cmd 0xE, CSND module writes this value here: 0 - (cmdword[2]>>16).
0x4 2 For Type0 Cmd 0xE, CSND module writes value 0 here.
0x6 2 For Type0 Cmd 0xE, CSND module writes value 0 here.
0x8 2 For Type0 Cmd 0xE, CSND module writes this value here: (u16)cmdword[4].
0xA 2 For Type0 Cmd 0xE, CSND module writes this value here: cmdword[4]>>16.
0xC 4 This is the audio data physical address, for the main channel.
0x10 4 This is the audio data total byte-size. The CSND module masks the size loaded from the Type0 command-data with value 0x7FFFFFF, which is then used when writing these registers.
0x14 4 This is the audio data physical address, for the second channel. When this is not 0x0 stereo audio is used, otherwise mono audio is used.
0x18 4 When CSND module handles type0 Cmd 0xE with encoding!=IMA-ADPCM, CSND module sets this to zero. This register can be initialized via CSND module type0 Cmd 0xB.
0x1C 4 CSND module writes value zero here immediately after it writes to chanslotreg+0x18.