;
; Standard joystick driver for the Creativision.
;
-; Christian Groessler, 2017-02-06
+; Christian Groessler, 2017-03-08
;
- .include "zeropage.inc"
+ .include "zeropage.inc"
- .include "joy-kernel.inc"
- .include "joy-error.inc"
- .include "creativision.inc"
+ .include "joy-kernel.inc"
+ .include "joy-error.inc"
+ .include "creativision.inc"
- .macpack module
+ .macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
- module_header _creativisionstd_joy
+ module_header _creativisionstd_joy
; Driver signature
- .byte $6A, $6F, $79 ; "joy"
- .byte JOY_API_VERSION ; Driver API version number
+ .byte $6A, $6F, $79 ; "joy"
+ .byte JOY_API_VERSION ; Driver API version number
; Library reference
- .addr $0000
+ .addr $0000
-; Button state masks (8 values)
+; Symbolic names for joystick masks (similar names like the defines in joystick.h, but not related to them)
- .byte $10 ; JOY_UP
- .byte $04 ; JOY_DOWN
- .byte $20 ; JOY_LEFT
- .byte $08 ; JOY_RIGHT
- .byte $01 ; JOY_FIRE (button #1)
- .byte $02 ; JOY_FIRE2 (button #2)
- .byte $00 ; Future expansion
- .byte $00 ; Future expansion
+JOY_UP = $10
+JOY_DOWN = $04
+JOY_LEFT = $20
+JOY_RIGHT = $08
+JOY_FIRE = $01
+JOY_FIRE2 = $02
+
+; Joystick state masks (8 values)
+
+ .byte JOY_UP
+ .byte JOY_DOWN
+ .byte JOY_LEFT
+ .byte JOY_RIGHT
+ .byte JOY_FIRE
+ .byte JOY_FIRE2
+ .byte $00 ; Future expansion
+ .byte $00 ; Future expansion
; Jump table.
- .addr INSTALL
- .addr UNINSTALL
- .addr COUNT
- .addr READJOY
- .addr 0 ; IRQ entry not used
+ .addr INSTALL
+ .addr UNINSTALL
+ .addr COUNT
+ .addr READJOY
+ .addr 0 ; IRQ entry not used
; ------------------------------------------------------------------------
; Constants
-JOY_COUNT = 2 ; Number of joysticks we support
+JOY_COUNT = 2 ; Number of joysticks we support
; ------------------------------------------------------------------------
; Code
- .code
+ .code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; Must return an JOY_ERR_xx code in a/x.
;
-INSTALL:
- lda #JOY_ERR_OK
- ldx #0
-; rts ; Fall through
+INSTALL: lda #JOY_ERR_OK
+ ldx #0
+; rts ; Fall through
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
-UNINSTALL:
- rts
+UNINSTALL: rts
; ------------------------------------------------------------------------
; COUNT: Return the total number of available joysticks in a/x.
;
-COUNT:
- lda #<JOY_COUNT
- ldx #>JOY_COUNT
- rts
+COUNT: lda #<JOY_COUNT
+ ldx #>JOY_COUNT
+ rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
-READJOY:
- and #1 ; fix joystick number
- bne READJOY_1 ; read right joystick
+READJOY: and #1 ; fix joystick number
+ bne READJOY_1 ; read right joystick
; Read left joystick
- ldx ZP_JOY0_DIR
- lda ZP_JOY0_BUTTONS
- jmp convert ; convert joystick state to sane cc65 values
+ ldx ZP_JOY0_DIR
+ lda ZP_JOY0_BUTTONS
+ jmp convert ; convert joystick state to cc65 values
; Read right joystick
-READJOY_1:
-
- ldx ZP_JOY1_DIR
- lda ZP_JOY1_BUTTONS
- lsr a
- lsr a
- ;jmp convert ; convert joystick state to sane cc65 values
- ; fall thru...
+READJOY_1: ldx ZP_JOY1_DIR
+ lda ZP_JOY1_BUTTONS
+ lsr a
+ lsr a
+ ;jmp convert ; convert joystick state to cc65 values
+ ; fall thru...
; ------------------------------------------------------------------------
; convert: make runtime lib compatible values
-; A - buttons
-; X - direction
+; inputs:
+; A - buttons
+; X - direction
;
convert:
- ldy #0
- sty retval ; initialize return value
; ------
; buttons:
- ; Port values are for the left hand joystick (right hand joystick
- ; values were shifted to the right to be identical).
- ; Why are there two bits indicating a pressed trigger?
- ; According to the "Second book of programs for the Dick Smith Wizard"
- ; (pg. 88ff), the left hand fire button gives the value of
- ; %00010001 and the right hand button gives %00100010
- ; Why two bits? Am I missing something? Can there be cases that just
- ; one of those bits is set?
- ; We just test if any of those two bits is not zero...
-
- tay
- and #%00010001
- beq cnv_1
-
- inc retval ; left button pressed
-
-cnv_1: tya
- and #%00100010
- beq cnv_2
-
- lda #$02
- ora retval
- sta retval ; right button pressed
+; Port values are for the left hand joystick (right hand joystick
+; values were shifted to the right to be identical).
+; Why are there two bits indicating a pressed trigger?
+; According to the "Second book of programs for the Dick Smith Wizard"
+; (pg. 88ff), the left hand fire button gives the value of
+; %00010001 and the right hand button gives %00100010
+; Why two bits? Can there be cases that just one of those bits is set?
+; Until these questions have been answered, we only use the lower two
+; bits and ignore the upper ones...
+
+ and #%00000011 ; button status came in in A, strip high bits
+ sta retval ; initialize 'retval' with button status
; ------
; direction:
-cnv_2: txa
- ; tested with https://sourceforge.net/projects/creativisionemulator
- ; $49 - %01001001 - up
- ; $41 - %01000001 - down
- ; $4D - %01001101 - left
- ; $45 - %01000101 - right
- ;
- ; are these correct? "Second book of programs for the Dick Smith Wizard" pg. 85 says something different
- ; ignored for now...
- ; $85 - %10000101 - up + right
- ; $8D - %10001101 - down + left
- ; $89 - %10001001 - up + left
- ; $85 - %10000101 - down + right (emulator bug?)
-
- bit testbit ; bit #0 set?
- beq done ; no, no direction
-
- and #%00001100 ; mask out other bits
- lsr a
- lsr a
- tax
- lda #%00000100 ; init bitmask
-loop: dex
- bmi done2
- asl a
- bne loop
-
-done2: ora retval
- rts
-
-done: lda retval
- rts
+; CV has a 16-direction joystick
+;
+; port values: (compass points)
+; N - $49 - %01001001
+; NNE - $48 - %01001000
+; NE - $47 - %01000111
+; ENE - $46 - %01000110
+; E - $45 - %01000101
+; ESE - $44 - %01000100
+; SE - $43 - %01000011
+; SSE - $42 - %01000010
+; S - $41 - %01000001
+; SSW - $40 - %01000000
+; SW - $4F - %01001111
+; WSW - $4E - %01001110
+; W - $4D - %01001101
+; WNW - $4C - %01001100
+; NW - $4B - %01001011
+; NNW - $4A - %01001010
+; center - $00 - %00000000
+;
+; mapping to cc65 definitions (4-direction joystick with 8 possible directions thru combinations)
+; N, E, S, W -> JOY_UP, JOY_RIGHT, JOY_DOWN, JOY_LEFT
+; NE, SE, SW, NW -> (JOY_UP | JOY_RIGHT), (JOY_DOWN | JOY_RIGHT), (JOY_DOWN | JOY_LEFT), (JOY_UP | JOY_LEFT)
+; NNE, ENE, ESE, SSE, SSW, WSW, WNW, NNW:
+; toggle between straight and diagonal direction for every call, e.g.
+; NNE:
+; call to READJOY: return JOY_UP | JOY_RIGHT
+; call to READJOY: return JOY_UP
+; call to READJOY: return JOY_UP | JOY_RIGHT
+; call to READJOY: return JOY_UP
+; call to READJOY: return JOY_UP | JOY_RIGHT
+; etc...
+
+ txa ; move direction status into A
+ beq done ; center position (no bits are set), nothing to do
+
+ and #$0F ; get rid of the "$40" bit
+ bit bit0 ; is it a "three letter" direction (NNE, ENE, etc.)?
+ beq special ; yes (bit #0 is zero)
+
+ lsr a ; create index into table
+ tax
+ lda dirtable,x
+done: ora retval ; include "button" bits
+ ldx #0
+ rts
+
+; NNE, ENE, ESE, SSE, SSW, WSW, WNW, NNW
+
+special: lsr a
+ tax
+
+ lda toggler ; toggle the toggler
+ eor #$01
+ sta toggler
+ bne spec_1 ; toggler is 1, use spectable_1 entry
+
+ lda spectable_0,x ; toggler is 0, use spectable_0 entry
+ bne done ; jump always
+
+spec_1: lda spectable_1,x
+ bne done ; jump always
; ------------------------------------------------------------------------
;
- .data
-testbit:.byte $01
+ .rodata
+
+ ; a mapping table of "port values" to "cc65 values"
+ ; port value had been shifted one bit to the right (range 0..7)
+dirtable: .byte JOY_DOWN ; S
+ .byte JOY_DOWN | JOY_RIGHT ; SE
+ .byte JOY_RIGHT ; E
+ .byte JOY_UP | JOY_RIGHT ; NE
+ .byte JOY_UP ; N
+ .byte JOY_UP | JOY_LEFT ; NW
+ .byte JOY_LEFT ; W
+ .byte JOY_DOWN | JOY_LEFT ; SW
+
+ ; two "special" mapping tables for three-letter directions (NNE, etc.)
+spectable_0: .byte JOY_DOWN ; SSW
+ .byte JOY_DOWN ; SSE
+ .byte JOY_RIGHT ; ESE
+ .byte JOY_RIGHT ; ENE
+ .byte JOY_RIGHT ; NNE
+ .byte JOY_UP ; NNW
+ .byte JOY_LEFT ; WNW
+ .byte JOY_LEFT ; WSW
+
+spectable_1: .byte JOY_DOWN | JOY_LEFT ; SSW
+ .byte JOY_DOWN | JOY_RIGHT ; SSE
+ .byte JOY_DOWN | JOY_RIGHT ; ESE
+ .byte JOY_UP | JOY_RIGHT ; ENE
+ .byte JOY_UP | JOY_RIGHT ; NNE
+ .byte JOY_UP | JOY_LEFT ; NNW
+ .byte JOY_UP | JOY_LEFT ; WNW
+ .byte JOY_DOWN | JOY_LEFT ; WSW
; ------------------------------------------------------------------------
;
- .bss
-retval: .res 0
+bit0: .byte $01
+
+; ------------------------------------------------------------------------
+;
+ .bss
+toggler: .res 1
+retval: .res 1
+
+ .end
projects / cc65 / commitdiff