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https://github.com/deater/dos33fsprogs.git
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33 lines
949 B
ArmAsm
33 lines
949 B
ArmAsm
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;=====================
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;=====================
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;=====================
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; ay3 write regs
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;=====================
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;=====================
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;=====================
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; write all 14 registers at AY_REGS
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ay3_write_regs:
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; bytes
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ldx #13 ; 2
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ay3_write_reg_loop:
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lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
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ldy #MOCK_AY_INACTIVE ; go inactive ; 2
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stx MOCK_6522_ORA1 ; put address on PA1 ; 3
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sta MOCK_6522_ORB1 ; latch_address on PB1 ; 3
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sty MOCK_6522_ORB1 ; 3
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; value
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lda AY_REGS,X ; 2
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sta MOCK_6522_ORA1 ; put value on PA1 ; 3
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lda #MOCK_AY_WRITE ; ; 2
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sta MOCK_6522_ORB1 ; write on PB1 ; 3
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sty MOCK_6522_ORB1 ; 3
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dex ; 1
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bpl ay3_write_reg_loop ; 2
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; rts
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