2 ; Standard joystick driver for the Creativision.
4 ; Christian Groessler, 2017-03-08
7 .include "zeropage.inc"
9 .include "joy-kernel.inc"
10 .include "joy-error.inc"
11 .include "creativision.inc"
16 ; ------------------------------------------------------------------------
17 ; Header. Includes jump table
19 module_header _creativisionstd_joy
23 .byte $6A, $6F, $79 ; "joy"
24 .byte JOY_API_VERSION ; Driver API version number
30 ; Symbolic names for joystick masks (similar names like the defines in joystick.h, but not related to them)
39 ; Joystick state masks (8 values)
47 .byte $00 ; Future expansion
48 .byte $00 ; Future expansion
56 .addr 0 ; IRQ entry not used
58 ; ------------------------------------------------------------------------
61 JOY_COUNT = 2 ; Number of joysticks we support
63 ; ------------------------------------------------------------------------
68 ; ------------------------------------------------------------------------
69 ; INSTALL routine. Is called after the driver is loaded into memory. If
70 ; possible, check if the hardware is present and determine the amount of
72 ; Must return an JOY_ERR_xx code in a/x.
75 INSTALL: lda #JOY_ERR_OK
79 ; ------------------------------------------------------------------------
80 ; UNINSTALL routine. Is called before the driver is removed from memory.
81 ; Can do cleanup or whatever. Must not return anything.
87 ; ------------------------------------------------------------------------
88 ; COUNT: Return the total number of available joysticks in a/x.
91 COUNT: lda #<JOY_COUNT
95 ; ------------------------------------------------------------------------
96 ; READ: Read a particular joystick passed in A.
99 READJOY: and #1 ; fix joystick number
100 bne READJOY_1 ; read right joystick
106 jmp convert ; convert joystick state to cc65 values
108 ; Read right joystick
110 READJOY_1: ldx ZP_JOY1_DIR
114 ;jmp convert ; convert joystick state to cc65 values
117 ; ------------------------------------------------------------------------
118 ; convert: make runtime lib compatible values
128 ; Port values are for the left hand joystick (right hand joystick
129 ; values were shifted to the right to be identical).
130 ; Why are there two bits indicating a pressed trigger?
131 ; According to the "Second book of programs for the Dick Smith Wizard"
132 ; (pg. 88ff), the left hand fire button gives the value of
133 ; %00010001 and the right hand button gives %00100010
134 ; Why two bits? Can there be cases that just one of those bits is set?
135 ; Until these questions have been answered, we only use the lower two
136 ; bits and ignore the upper ones...
138 and #%00000011 ; button status came in in A, strip high bits
139 sta retval ; initialize 'retval' with button status
143 ; CV has a 16-direction joystick
145 ; port values: (compass points)
146 ; N - $49 - %01001001
147 ; NNE - $48 - %01001000
148 ; NE - $47 - %01000111
149 ; ENE - $46 - %01000110
150 ; E - $45 - %01000101
151 ; ESE - $44 - %01000100
152 ; SE - $43 - %01000011
153 ; SSE - $42 - %01000010
154 ; S - $41 - %01000001
155 ; SSW - $40 - %01000000
156 ; SW - $4F - %01001111
157 ; WSW - $4E - %01001110
158 ; W - $4D - %01001101
159 ; WNW - $4C - %01001100
160 ; NW - $4B - %01001011
161 ; NNW - $4A - %01001010
162 ; center - $00 - %00000000
164 ; mapping to cc65 definitions (4-direction joystick with 8 possible directions thru combinations)
165 ; N, E, S, W -> JOY_UP, JOY_RIGHT, JOY_DOWN, JOY_LEFT
166 ; NE, SE, SW, NW -> (JOY_UP | JOY_RIGHT), (JOY_DOWN | JOY_RIGHT), (JOY_DOWN | JOY_LEFT), (JOY_UP | JOY_LEFT)
167 ; NNE, ENE, ESE, SSE, SSW, WSW, WNW, NNW:
168 ; toggle between straight and diagonal direction for every call, e.g.
170 ; call to READJOY: return JOY_UP | JOY_RIGHT
171 ; call to READJOY: return JOY_UP
172 ; call to READJOY: return JOY_UP | JOY_RIGHT
173 ; call to READJOY: return JOY_UP
174 ; call to READJOY: return JOY_UP | JOY_RIGHT
177 txa ; move direction status into A
178 beq done ; center position (no bits are set), nothing to do
180 and #$0F ; get rid of the "$40" bit
181 bit bit0 ; is it a "three letter" direction (NNE, ENE, etc.)?
182 beq special ; yes (bit #0 is zero)
184 lsr a ; create index into table
187 done: ora retval ; include "button" bits
191 ; NNE, ENE, ESE, SSE, SSW, WSW, WNW, NNW
196 lda toggler ; toggle the toggler
199 bne spec_1 ; toggler is 1, use spectable_1 entry
201 lda spectable_0,x ; toggler is 0, use spectable_0 entry
202 bne done ; jump always
204 spec_1: lda spectable_1,x
205 bne done ; jump always
207 ; ------------------------------------------------------------------------
211 ; a mapping table of "port values" to "cc65 values"
212 ; port value had been shifted one bit to the right (range 0..7)
213 dirtable: .byte JOY_DOWN ; S
214 .byte JOY_DOWN | JOY_RIGHT ; SE
216 .byte JOY_UP | JOY_RIGHT ; NE
218 .byte JOY_UP | JOY_LEFT ; NW
220 .byte JOY_DOWN | JOY_LEFT ; SW
222 ; two "special" mapping tables for three-letter directions (NNE, etc.)
223 spectable_0: .byte JOY_DOWN ; SSW
225 .byte JOY_RIGHT ; ESE
226 .byte JOY_RIGHT ; ENE
227 .byte JOY_RIGHT ; NNE
232 spectable_1: .byte JOY_DOWN | JOY_LEFT ; SSW
233 .byte JOY_DOWN | JOY_RIGHT ; SSE
234 .byte JOY_DOWN | JOY_RIGHT ; ESE
235 .byte JOY_UP | JOY_RIGHT ; ENE
236 .byte JOY_UP | JOY_RIGHT ; NNE
237 .byte JOY_UP | JOY_LEFT ; NNW
238 .byte JOY_UP | JOY_LEFT ; WNW
239 .byte JOY_DOWN | JOY_LEFT ; WSW
241 ; ------------------------------------------------------------------------
245 ; ------------------------------------------------------------------------