pureikyubu/Docs/HW/cp.txt

    All registers are 16-bit only. All bits are in little-endian format 
    (mask for bit 0 is 0x0001).

CP_SR - Command Processor Status Register [CC000000] R
    bit 0 : fifo overflow (wrptr > hiWatermark)
    bit 1 : fifo underlow (rdptr > loWatermark)
    bit 2 : GP is idle for reading (1 : idle)
    bit 3 : GP is idle for commands (1 : idle)
    bit 4 : breakpoint interrupt
    (other bits are reserved)

CP_CR - Command Processor Control Register [CC000002] R/W
    bit 0 : enable reading of fifo by GP
    bit 1 : write 1, to clear breakpoint interrupt ?
    bit 2 : enable overflow checks (high watermark)
    bit 3 : enable underlow checks (low watermark)
    bit 4 : link GP and CPU fifos
    bit 5 : enable breakpoint checks ?
    (other bits are reserved)

CP_CLR - Command Processor Clear Register [CC000004] W
    bit 0 : write 1, to clear fifo overflow
    bit 1 : write 1, to clear fifo underlow
    (other bits are reserved)

CP_BASEL [CC000020] R/W
CP_BASEH [CC000022] R/W
    fifo base physical address

CP_TOPL [CC000024] R/W
CP_TOPH [CC000026] R/W
    fifo top physical address

CP_HIWMARKL [CC000028] R/W
CP_HIWMARKH [CC00002A] R/W
    high watermark physical address

CP_LOWMARKL [CC00002C] R/W
CP_LOWMARKH [CC00002E] R/W
    low watermark physical address

CP_CNTL [CC000030] R/W
CP_CNTH [CC000032] R/W
    distance between read and write pointers (count)

CP_WRPTRL [CC000034] R/W
CP_WRPTRH [CC000036] R/W
    GP fifo write pointer (physical address)

CP_RDPTRL [CC000038] R/W
CP_RDPTRH [CC00003A] R/W
    GP fifo read pointer (physical address)

CP_BPPTRL [CC00003C] R/W
CP_BPPTRH [CC00003E] R/W
    GP fifo breakpoint (physical address)