.byte $04 ; JOY_LEFT
.byte $08 ; JOY_RIGHT
.byte $10 ; JOY_FIRE
- .byte $00 ; Future expansion
+ .byte $00 ; JOY_FIRE2 unavailable
.byte $00 ; Future expansion
.byte $00 ; Future expansion
; Jump table.
- .word INSTALL
- .word DEINSTALL
- .word COUNT
- .word READ
+ .addr INSTALL
+ .addr UNINSTALL
+ .addr COUNT
+ .addr READ
+ .addr IRQ
; ------------------------------------------------------------------------
; Constants
;
INSTALL:
- sei
- lda $0314
- sta irqjmp+1
- lda $0315
- sta irqjmp+2
- lda #<pollirq
- sta $0314
- lda #>pollirq
- sta $0315
- cli
-
lda #<JOY_ERR_OK
ldx #>JOY_ERR_OK
- rts
+; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
-; DEINSTALL routine. Is called before the driver is removed from memory.
+; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
-DEINSTALL:
- sei
- lda irqjmp+1
- sta $0314
- lda irqjmp+2
- sta $0315
- cli
+UNINSTALL:
rts
; ------------------------------------------------------------------------
-; we must use an irq here since we need timers
-; which otherwhise would conflict with system-irq
-pollirq:
- ; cia 2 setup
-
- ldy #$00 ; port b direction
- sty $dd03 ; => input
-
- sty $dd05 ; cia2 timer a highbyte
- sty $dc05 ; cia1 timer a highbyte
- iny
- sty $dd04 ; cia2 timer a lowbyte
- sty $dc04 ; cia1 timer a lowbyte
-
- lda #%00010001
- sta $dd0e ; control register a
- ; timer: start
- ; continous
- ; forced load
- ; serial port: input
-
- ; cia 1 setup
- lda #%01010001
- sta $dc0e ; control register a
- ; timer: start
- ; continous
- ; forced load
- ; serial port: output
-
-
- ; read directions 3
- lda $dd01 ;read cia 2 port b
- and #$0f
- sta temp3
-
- ; read button 3
- lda $dd02 ;cia 2 port a
- and #%11111011 ;data direction
- sta $dd02 ;=> bit 2 input
-
- lda $dd00 ;read cia 2 p.A
- and #%00000100 ;check bit 2
- asl a
- asl a
- ora temp3
- sta temp3
-
- ; read directions 4
- lda $dd01 ;read cia 2 port b
- lsr a
- lsr a
- lsr a
- lsr a
- sta temp4
-
- ; read button 4
- ldx #$ff ;serial data register
- stx $dc0c;=> writing $ff causes
- ;cia to output some
- ;count signals at cnt1
-
- ldx $dd0c ;read cia 2 serial in
- beq fire ;button press if zero
-
- lda temp4
- ora #%00010000
- sta temp4
+; IRQ entry point. Is called from the C layer as a subroutine in the
+; interrupt.
+
+IRQ: ; cia 2 setup
+
+ ldy #$00 ; port b direction
+ sty $dd03 ; => input
+
+ sty $dd05 ; cia2 timer a highbyte
+ sty $dc05 ; cia1 timer a highbyte
+ iny
+ sty $dd04 ; cia2 timer a lowbyte
+ sty $dc04 ; cia1 timer a lowbyte
+
+ lda #%00010001
+ sta $dd0e ; control register a
+ ; timer: start
+ ; continous
+ ; forced load
+ ; serial port: input
+
+ ; cia 1 setup
+ lda #%01010001
+ sta $dc0e ; control register a
+ ; timer: start
+ ; continous
+ ; forced load
+ ; serial port: output
+
+ ; read directions 3
+ lda $dd01 ;read cia 2 port b
+ and #$0f
+ sta temp3
+
+ ; read button 3
+ lda $dd02 ;cia 2 port a
+ and #%11111011 ;data direction
+ sta $dd02 ;=> bit 2 input
+
+ lda $dd00 ;read cia 2 p.A
+ and #%00000100 ;check bit 2
+ asl a
+ asl a
+ ora temp3
+ sta temp3
+
+ ; read directions 4
+ lda $dd01 ;read cia 2 port b
+ lsr a
+ lsr a
+ lsr a
+ lsr a
+ sta temp4
+
+ ; read button 4
+ ldx #$ff ;serial data register
+ stx $dc0c ;=> writing $ff causes
+ ;cia to output some
+ ;count signals at cnt1
+
+ ldx $dd0c ;read cia 2 serial in
+ beq fire ;button press if zero
+
+ lda temp4
+ ora #%00010000
+ sta temp4
fire:
+ ; Default Value: $40/64 on PAL
+ ; $42/66 on NTSC
+ lda #$41
+ sta $dc05
+ ; Default Value: $25/37 on PAL
+ ; $95/149 on NTSC
+ lda #0
+ sta $dc04
- ; Default Value: $40/64 on PAL
- ; $42/66 on NTSC
- lda #$41
- sta $dc05
- ; Default Value: $25/37 on PAL
- ; $95/149 on NTSC
- lda #0
- sta $dc04
-
-irqjmp: jmp $dead
+ rts
; ------------------------------------------------------------------------
; COUNT: Return the total number of available joysticks in a/x.
;
-COUNT:
- lda #<JOY_COUNT
+COUNT: lda #<JOY_COUNT
ldx #>JOY_COUNT
rts
; READ: Read a particular joystick passed in A.
;
-READ:
- tax ; Joystick number into X
+READ: tax ; Joystick number into X
bne joy2
- ; Read joystick 1
-joy1:
- lda #$7F
+; Read joystick 1
+
+joy1: lda #$7F
sei
sta CIA1_PRA
lda CIA1_PRB
eor #$1F
rts
- ; Read joystick 2
-joy2:
- dex
+; Read joystick 2
+
+joy2: dex
bne joy3
; ldx #0
; Read joystick 3
-joy3:
- dex
- bne joy4
+joy3: dex
+ bne joy4
- lda temp3
+ lda temp3
eor #$1F
- ldx #0
rts
; Read joystick 4
-joy4:
- lda temp4
+joy4: lda temp4
eor #$1F
- ldx #0
+ ldx #0
rts
.byte $20 ; JOY_LEFT "4"
.byte $08 ; JOY_RIGHT "6"
.byte $04 ; JOY_FIRE "5" ENTER
- .byte $00 ; Future expansion
+ .byte $00 ; JOY_FIRE2 unavailable
.byte $00 ; Future expansion
.byte $00 ; Future expansion
; Jump table.
- .word INSTALL
- .word UNINSTALL
- .word COUNT
- .word READ
+ .addr INSTALL
+ .addr UNINSTALL
+ .addr COUNT
+ .addr READ
+ .addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; Constants
;
INSTALL:
- lda VIC_CLK_128
- cmp #$FF
- bne @C128
- lda #JOY_ERR_NO_DEVICE
- .byte $2C
-@C128: lda #JOY_ERR_OK
- ldx #0
+ lda #JOY_ERR_OK ; Assume we have a joystick
+ ldx VIC_CLK_128 ; Test for a C128
+ cpx #$FF
+ bne @C128 ; Jump if we have one
+ lda #JOY_ERR_NO_DEVICE ; No C128 -> no numpad
+@C128: ldx #0 ; Set high byte
; rts ; Run into UNINSTALL instead
projects / cc65 / commitdiff