98 lines
2.0 KiB
ArmAsm
98 lines
2.0 KiB
ArmAsm
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.align $100
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;====================================
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; mb_write_frame
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;====================================
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; cycle counted
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; 2 + 13*(70) + 74 + 5 = 991
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mb_write_frame:
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ldx #0 ; set up reg count ; 2
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;============
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; 2
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;==================================
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; loop through the 14 registers
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; reading the value, then write out
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;==================================
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mb_write_loop:
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;=============================
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; not r13 -- 4+5+28+26+7 = 70
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; r13, not ff -- 4+5+ 4 +28+26+7 = 74
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; r13 is ff -- 4+5+3+1=[61] = 74
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lda AY_REGISTERS,X ; load register value ; 4
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; special case R13. If it is 0xff, then don't update
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; otherwise might spuriously reset the envelope settings
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cpx #13 ; 2
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bne mb_not_13 ; 3
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; -1
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cmp #$ff ; 2
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bne mb_not_13 ; 3
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; -1
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; delay 61
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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inc TEMP ; 5
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lda TEMP ; 3
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jmp mb_skip_13 ; 3
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mb_not_13:
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; address
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stx MOCK_6522_ORA1 ; put address on PA1 ; 4
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stx MOCK_6522_ORA2 ; put address on PA2 ; 4
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ldy #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
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sty MOCK_6522_ORB1 ; latch_address on PB1 ; 4
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sty MOCK_6522_ORB2 ; latch_address on PB2 ; 4
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ldy #MOCK_AY_INACTIVE ; go inactive ; 2
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sty MOCK_6522_ORB1 ; 4
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sty MOCK_6522_ORB2 ; 4
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;==========
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; 28
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; value
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sta MOCK_6522_ORA1 ; put value on PA1 ; 4
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sta MOCK_6522_ORA2 ; put value on PA2 ; 4
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lda #MOCK_AY_WRITE ; ; 2
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sta MOCK_6522_ORB1 ; write on PB1 ; 4
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sta MOCK_6522_ORB2 ; write on PB2 ; 4
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sty MOCK_6522_ORB1 ; 4
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sty MOCK_6522_ORB2 ; 4
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;===========
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; 26
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mb_no_write:
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inx ; point to next register ; 2
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cpx #14 ; if 14 we're done ; 2
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bmi mb_write_loop ; otherwise, loop ; 3
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;============
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; 7
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mb_skip_13:
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; -1
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rts ; 6
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pt3_loop_smc:
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.byte $0,$0
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