MAKOTO V3 driver

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: ?