MAKOTO V3 driver

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Cold boot process

  • DI, SP at $FFFC, IM=1
  • Clear $F800~$FFFF
  • Clear the command buffer (128 bytes) and pointers
  • Silences FM, PCM and SSG
  • OUT ($C0),A = 1
  • stuff with timer A
  • banks init:
ld      a,#1e
in      a,(#08)
ld      a,#0e
in      a,(#09)
ld      a,#06
in      a,(#0a)
ld      a,#02
in      a,(#0b)
  • Reset FM
  • out (#08),a
  • EI
  • loop while buffer read index = buffer in index
  • inc buffer read index
  • AND index with $3F (keeps it under 64)
  • Reads buffer, clears entry to 0
  • If command = 0, read R, out (#0c),a and loop back to EI
  • If command != 0:
  • Translate command by LUT, ret if =0, can be anything 1~5.
  • LUT is something like 0,1...,2...,0...,5...,0...4...,0...,3,3
  • 1:Special command, uses a jump table (0~27)
    • 0:RET, should not happen
    • 1:DI,reset banks,out (#0c),a=0, wait,out (#0c),a=0 again, init YM2610, out (#0c),a=1

Has a 2*64 byte command FIFO.

  • Command 5: Stop music (pause ?)
  • Command 7: Play music in following byte
  • Command A: Fade, speed in following byte
  • Command E: Set music speed

Command type translation table at $4FAF.

  • 0: Ignore
  • 1: Special command
  • 2: ?
  • 3: ?
  • 4: ?
  • 5: ?