Short documentation for sceDMA:     (Translated by psx_kai / Dok. Vers. 1.1)

1. Register Map:

DMA:
	Channel 0: 10008000 VIF0	(included in Reset yes)
	Channel 1: 10009000 VIF1	(included in Reset yes)
	Channel 2: 1000A000 GIF		(included in Reset yes)
	Channel 3: 1000B000 fromIPU	(included in Reset yes)
	Channel 4: 1000B400 toIPU	(included in Reset yes)
	Channel 5: 1000C000 SIF0	(included in Reset no)
	Channel 6: 1000C400 SIF1	(included in Reset no)
	Channel 7: 1000C800 SIF2	(included in Reset no)
	Channel 8: 1000D000 from SPR	(included in Reset yes)
	Channel 9: 1000D400 toSPR	(included in Reset yes)
	CommonReg: 1000E000

DMA Channel Registers:
	CHCR 00 (DIR 001 / STR 100)
	MADR 10
	QWC  20
	TADR 30
	ASR0 40
	ASR1 50
        SADR 80

DMA Common Registers:
	CTRL    1000E000 
	STAT    1000E010
	PCR     1000E020
	SQWC    1000E030
	RBSR    1000E040
	RBOR    1000E050
	STADR   1000E060
	ENABLEW

HW:
  10000000 HW-Base
  10003020 GIF-STAT

2. Functions

sceDMAReset:
    This functions performs all full reset of the DMA-Channels. After reset
    you can use them all.

    1. step:

    It writes per Channel:
    CH	..80 = 0
    CH	..00 = 0
    CH	..30 = 0
    CH	..10 = 0
    CH	..50 = 0
    CH	..40 = 0

    2. step:
    1000E010 = 0000FF1F
    1000E010 = (1000E010) AND FF1F0000

    3. step:
    Call memclr with a0=sp and a1=20
    (Set 20 Byte on stack to 0) RC = -1 if a0=0, otherwise RC = 0.
    RC will not be uses in sceDmaReset!!!

    4. step:
    Call sceDmaPutEnv with a0=sp
      On base of the environment pointed to by sp (Bytes 0(sp)-17(sp)) 
      the DMA Common Registers will be set.
      The following Adresses will be written:
	1000E000
	1000E020
	1000E030
	1000E050
	1000E040
      Afterwards the environment will be copied to Adress sceDmaCurrEnv.
      The first for Bytes of the environment will be checked to be lower 10
      (the perhaps are DMA-Channel-numbers).
      If they are, the returncode is as follows:
	1. Byte>=10 => RC -1 
	2. Byte>=10 => RC -2 
	3. Byte>=10 => RC -3 
	4. Byte>=10 => RC -4
    RC will not be uses in sceDmaReset!!!
    Based on the values of those first 4 Bytes the value to be written to
    1000E000 is calculated.
    The additional Bytes of the environment are halfwords and are calculated
    for setting the other Command Registers.

    5. step:
    If Parameter a0=1, then after Reset of Bit 0 in 1000E000 it will be set to 1.

    6. step:
    The return code is the value of Bit 0 from 1000E000

sceDmaGetChan:
    sceDmaGetChan fetches as returncode the DMA-baseaddress
    for the in a0 specified dma-channel.
    RC = 0 if a0 >= 10.

psx_kai 04/2001
psx_kai@yahoo.de