chiptune: initial playing
This commit is contained in:
Vince Weaver
parent
59ff72b39a
commit
67cf2d7b4b
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@ -0,0 +1,219 @@
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; Mockingboad programming:
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; + Has two 6522 I/O chips connected to two AY-3-8910 chips
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; + Optionally has some speech chips controlled via the outport on the AY
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; + Often in slot 4
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; TODO: how to auto-detect?
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; References used:
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; http://macgui.com/usenet/?group=2&id=8366
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; 6522 Data Sheet
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; AY-3-8910 Data Sheet
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;========================
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; Mockingboard card
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; Essentially two 6522s hooked to the Apple II bus
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; Connected to AY-3-8910 chips
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; PA0-PA7 on 6522 connected to DA0-DA7 on AY
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; PB0 on 6522 connected to BC1
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; PB1 on 6522 connected to BDIR
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; PB2 on 6522 connected to RESET
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; left speaker
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MOCK_6522_ORB1 EQU $C400 ; 6522 #1 port b data
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MOCK_6522_ORA1 EQU $C401 ; 6522 #1 port a data
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MOCK_6522_DDRB1 EQU $C402 ; 6522 #1 data direction port B
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MOCK_6522_DDRA1 EQU $C403 ; 6522 #1 data direction port A
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; right speaker
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MOCK_6522_ORB2 EQU $C480 ; 6522 #2 port b data
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MOCK_6522_ORA2 EQU $C481 ; 6522 #2 port a data
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MOCK_6522_DDRB2 EQU $C482 ; 6522 #2 data direction port B
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MOCK_6522_DDRA2 EQU $C483 ; 6522 #2 data direction port A
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; AY-3-8910 commands on port B
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; RESET BDIR BC1
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MOCK_AY_RESET EQU $0 ; 0 0 0
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MOCK_AY_INACTIVE EQU $4 ; 1 0 0
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MOCK_AY_READ EQU $5 ; 1 0 1
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MOCK_AY_WRITE EQU $6 ; 1 1 0
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MOCK_AY_LATCH_ADDR EQU $7 ; 1 1 1
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;========================
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; Mockingboard Init
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;========================
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; Initialize the 6522s
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; set the data direction for all pins of PortA/PortB to be output
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mockingboard_init:
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lda #$ff ; all output (1)
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sta MOCK_6522_DDRB1
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sta MOCK_6522_DDRA1
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sta MOCK_6522_DDRB2
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sta MOCK_6522_DDRA2
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rts
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;======================
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; Reset Left AY-3-8910
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;======================
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reset_ay_both:
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lda #MOCK_AY_RESET
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sta MOCK_6522_ORB1
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lda #MOCK_AY_INACTIVE
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sta MOCK_6522_ORB1
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;======================
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; Reset Right AY-3-8910
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;======================
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;reset_ay_right:
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lda #MOCK_AY_RESET
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sta MOCK_6522_ORB2
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lda #MOCK_AY_INACTIVE
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sta MOCK_6522_ORB2
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rts
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; Write sequence
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; Inactive -> Latch Address -> Inactive -> Write Data -> Inactive
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;=======================
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; Write Right AY-3-8910
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;=======================
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; register in X
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; value in MB_VALUE
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write_ay_both:
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; address
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stx MOCK_6522_ORA1 ; put address on PA
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lda #MOCK_AY_LATCH_ADDR ; latch_address on PB
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sta MOCK_6522_ORB1
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lda #MOCK_AY_INACTIVE ; go inactive
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sta MOCK_6522_ORB1
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; value
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lda MB_VALUE
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sta MOCK_6522_ORA1 ; put value on PA
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lda #MOCK_AY_WRITE ; write on PB
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sta MOCK_6522_ORB1
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lda #MOCK_AY_INACTIVE ; go inactive
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sta MOCK_6522_ORB1
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;=======================
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; Write Left AY-3-8910
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;=======================
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;write_ay_left:
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; address
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stx MOCK_6522_ORA2 ; put address on PA
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lda #MOCK_AY_LATCH_ADDR ; latch_address on PB
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sta MOCK_6522_ORB2
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lda #MOCK_AY_INACTIVE ; go inactive
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sta MOCK_6522_ORB2
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; value
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lda MB_VALUE
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sta MOCK_6522_ORA2 ; put value on PA
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lda #MOCK_AY_WRITE ; write on PB
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sta MOCK_6522_ORB2
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lda #MOCK_AY_INACTIVE ; go inactive
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sta MOCK_6522_ORB2
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rts
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;=======================================
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; clear ay -- clear all 14 AY registers
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; should silence the card
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;=======================================
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clear_ay_both:
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ldx #14
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lda #0
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sta MB_VALUE
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clear_ay_left_loop:
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jsr write_ay_both
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dex
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bpl clear_ay_left_loop
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rts
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;=======================================
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; Detect a Mockingboard card
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;=======================================
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; Based on code from the French Touch "Pure Noise" Demo
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; Attempts to time an instruction sequence with a 6522
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;
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; If found, puts in bMB
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; MB_ADDRL:MB_ADDRH has address of Mockingboard
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; returns X=0 if not found, X=1 if found
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mockingboard_detect:
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lda #0
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sta MB_ADDRL
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mb_detect_loop: ; self-modifying
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lda #$07 ; we start in slot 7 ($C7) and go down to 0 ($C0)
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ora #$C0 ; make it start with C
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sta MB_ADDRH
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ldy #04 ; $CX04
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ldx #02 ; 2 tries?
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mb_check_cycle_loop:
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lda (MB_ADDRL),Y ; timer 6522 (Low Order Counter)
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; count down
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sta TEMP ; 3 cycles
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lda (MB_ADDRL),Y ; + 5 cycles = 8 cycles
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; between the two accesses to the timer
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sec
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sbc TEMP ; subtract to see if we had 8 cycles
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cmp #$f8 ; -8
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bne mb_not_in_this_slot
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dex ; decrement, try one more time
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bne mb_check_cycle_loop ; loop detection
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inx ; Mockingboard found (X=1)
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done_mb_detect:
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;stx bMB ; store result to bMB
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rts ; return
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mb_not_in_this_slot:
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dec mb_detect_loop+1 ; decrement the "slot" (self_modify)
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bne mb_detect_loop ; loop down to one
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ldx #00
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beq done_mb_detect
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;=======================================
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; Detect a Mockingboard card in Slot4
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;=======================================
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; Based on code from the French Touch "Pure Noise" Demo
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; Attempts to time an instruction sequence with a 6522
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;
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; MB_ADDRL:MB_ADDRH has address of Mockingboard
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; returns X=0 if not found, X=1 if found
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mockingboard_detect_slot4:
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lda #0
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sta MB_ADDRL
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mb4_detect_loop: ; self-modifying
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lda #$04 ; we're only looking in Slot 4
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ora #$C0 ; make it start with C
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sta MB_ADDRH
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ldy #04 ; $CX04
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ldx #02 ; 2 tries?
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mb4_check_cycle_loop:
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lda (MB_ADDRL),Y ; timer 6522 (Low Order Counter)
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; count down
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sta TEMP ; 3 cycles
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lda (MB_ADDRL),Y ; + 5 cycles = 8 cycles
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; between the two accesses to the timer
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sec
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sbc TEMP ; subtract to see if we had 8 cycles
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cmp #$f8 ; -8
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bne mb4_not_in_this_slot
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dex ; decrement, try one more time
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bne mb4_check_cycle_loop ; loop detection
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inx ; Mockingboard found (X=1)
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done_mb4_detect:
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rts ; return
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mb4_not_in_this_slot:
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ldx #00
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beq done_mb4_detect
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@ -5,8 +5,10 @@ PNG2GR = ../gr-utils/png2gr
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all: mock_player.dsk
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mock_player.dsk: CHIPTUNE_PLAYER
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mock_player.dsk: CHIPTUNE_PLAYER OUT.0
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$(DOS33) -y mock_player.dsk BSAVE -a 0x1000 CHIPTUNE_PLAYER
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$(DOS33) -y mock_player.dsk BSAVE -a 0x4000 OUT.0
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CHIPTUNE_PLAYER: chiptune_player.o
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ld65 -o CHIPTUNE_PLAYER chiptune_player.o -C ../linker_scripts/apple2_1000.inc
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Binary file not shown.
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@ -15,7 +15,7 @@
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sta DONE_PLAYING
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sta XPOS
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lda #1
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lda #0
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sta MB_FRAME_DIFF
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lda #<mocking_message ; load loading message
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@ -50,23 +50,19 @@ mockingboard_found:
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;============================
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jsr mockingboard_init
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jsr reset_ay_left
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jsr reset_ay_right
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jsr clear_ay_left
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jsr clear_ay_right
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jsr reset_ay_both
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jsr clear_ay_both
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;===========================
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; load pointer to the music
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; init pointer to the music
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;===========================
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; lda #<ksp_theme
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; sta INL
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; lda #>ksp_theme
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; sta INH
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; lda (INL),Y ; read in frame delay
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; sta MB_FRAME_DIFF
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; inc INL ; FIXME: should check if we oflowed
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lda #$40
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sta INH
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lda #$00
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sta INL
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lda #$0
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sta MB_CHUNK
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;=========================
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; Setup Interrupt Handler
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@ -105,7 +101,7 @@ mockingboard_found:
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; Enable 6502 interrupts
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;============================
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;
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; cli ; clear interrupt mask
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cli ; clear interrupt mask
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;============================
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@ -147,8 +143,7 @@ done_play:
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sei ; disable interrupts
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jsr clear_ay_left
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jsr clear_ay_right
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jsr clear_ay_both
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lda #0
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sta CH
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@ -179,100 +174,53 @@ interrupt_handler:
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pha ; save A
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; Should we save X and Y too?
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inc $0404 ; debug
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bit $C404 ; can clear 6522 interrupt by reading T1C-L
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inc $0401 ; DEBUG: increment text char
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ldy MB_FRAME_DIFF
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dec MB_FRAME_DIFF
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bne done_interrupt
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ldx #0
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mb_write_loop:
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lda (INL),y
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cpx #13
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bne mb_not_13
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cmp #$ff
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beq skip_r13
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ldy #0
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bottom_regs:
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lda (INL),Y ; load low reg bitmask
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sta MASK
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ldx #$ff ; init to -1
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bottom_regs_loop:
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inx ; increment X
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cpx #$8 ; if we reach 8, done
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beq top_regs ; move on to top
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ror MASK
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bcc bottom_regs_loop ; if bit not set in mask, skip reg
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stx XX ; save X
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iny ; get next output value
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lda (INL),Y ; read in value
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sty YY ; save Y
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tax ; value in X
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ldy XX ; register# in Y
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; reg in Y, value in X
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jsr write_ay_left ; assume 3 channel (not six)
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jsr write_ay_right ; so write same to both left/write
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ldx XX ; restore X
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ldy YY ; restore Y
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jmp bottom_regs_loop ; loop
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top_regs:
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iny ; point to next value
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lda (INL),Y ; load top reg bitmask
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sta MASK
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ldx #$7 ; load X as 7 (we increment first)
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top_regs_loop:
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inx ; increment
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cpx #16
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beq done_with_masks ; exit if done
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ror MASK
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bcc top_regs_loop ; loop if not set
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stx XX ; save X value
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iny ; point to value
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lda (INL),Y ; read in output value
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sty YY ; save Y value
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tax ; value in X
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ldy XX ; register in Y
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; reg in Y, value in X
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jsr write_ay_left ; assume 3 channel (not six)
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jsr write_ay_right ; so write same to both left/write
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ldx XX
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ldy YY
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jmp top_regs_loop
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done_with_masks:
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new_frame_diff:
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iny
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lda (INL),Y ; read in frame delay
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cmp #$ff ; see if end
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bne not_done ; if so, done
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inc DONE_PLAYING ; set done playing flag
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jmp done_interrupt
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not_done:
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sta MB_FRAME_DIFF
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iny
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mb_not_13:
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sta MB_VALUE
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; INLINE?
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jsr write_ay_both ; assume 3 channel (not six)
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; so write same to both left/write
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clc
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tya
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adc INL
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sta INL
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lda #0
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adc INH
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lda INH
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adc #$4
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sta INH
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inx
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cpx #14
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bmi mb_write_loop
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skip_r13:
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lda MB_CHUNK
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clc
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adc #$40
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sta INH
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inc MB_FRAME_DIFF
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bne done_interrupt
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wraparound:
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inc MB_CHUNK
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lda MB_CHUNK
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cmp #$4
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bne chunk_good
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lda #0
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sta MB_CHUNK
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chunk_good:
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done_interrupt:
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pla
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rti
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@ -286,7 +234,7 @@ done_interrupt:
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;=========
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.include "../asm_routines/gr_offsets.s"
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.include "../asm_routines/text_print.s"
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.include "../asm_routines/mockingboard.s"
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.include "../asm_routines/mockingboard_a.s"
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.include "../asm_routines/lzss_decompress.s"
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.include "../asm_routines/gr_fast_clear.s"
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.include "../asm_routines/pageflip.s"
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Binary file not shown.
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@ -100,6 +100,8 @@ KEY_OFFSET EQU $8D
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DRAW_BLUE_SKY EQU $8E
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RANDOM_POINTER EQU $8F
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FRAME_COUNT EQU $90
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MB_VALUE EQU $91
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MB_CHUNK EQU $92
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MB_ADDRL EQU $91
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MB_ADDRH EQU $92
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DONE_PLAYING EQU $93
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