DSP
From xboxdevwiki
The DSPs in the APU are probably "Parthus MediaStream" DSP core (DSP24210/DSP2420?).
Those are similar to Motorola DSP56362 (DSP56300 Family). If so, the datasheet can be found at http://www.nxp.com/docs/en/data-sheet/DSP56362.pdf (Also see "Documentation" section in said datasheet for the related documentation)
Memory Size
| Program RAM Size | X Data RAM Size | Y Data RAM Size | |
|---|---|---|---|
| GP | 4096[FIXME] x 24-bit | 4096 x 24-bit | 2048 x 24-bit |
| EP | 4096[FIXME] x 24-bit | 3072 x 24-bit | 256 x 24-bit |
Other datasheets for similar DSPs suggest that the memory sizes might be different if instruction cache or switch mode are toggled. It is currently unknown if the DSPs in the Xbox APU support a similar feature[FIXME].
DMA
This section is very incomplete and not much was tested on hardware either
Sample formats:
- 0x0 = 8 bit
- 0x1 = 16 bit
- 0x2 = 24 bit in MSB
- 0x3 = 32 bit
- 0x4
- 0x5
- 0x6 = 24 bit in LSB (also endianess switched?[citation needed])
- 0x7
Buffers:
- 0x0 = FIFO0
- 0x1 = FIFO1
- 0x2 = FIFO2[citation needed]
- 0x3 = FIFO3[citation needed]
- 0x4
- 0x5
- 0x6
- 0x7
- 0x8
- 0x9
- 0xA
- 0xB
- 0xC
- 0xD
- 0xE = Circular
- 0xF
