dos33fsprogs/music/tiny_tracker5/ay3_write_regs.s

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2022-01-19 04:53:24 +00:00
;=====================
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; ay3 write regs
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;=====================
;=====================
; write all 14 registers at AY_REGS
ay3_write_regs:
ldx #13
ay3_write_reg_loop:
lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
ldy #MOCK_AY_INACTIVE ; go inactive ; 2
stx MOCK_6522_ORA1 ; put address on PA1 ; 4
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
sty MOCK_6522_ORB1 ; 4
; value
lda AY_REGS,X
sta MOCK_6522_ORA1 ; put value on PA1 ; 4
lda #MOCK_AY_WRITE ; ; 2
sta MOCK_6522_ORB1 ; write on PB1 ; 4
sty MOCK_6522_ORB1 ; 4
dex
bpl ay3_write_reg_loop
; rts