1
0
mirror of https://github.com/cc65/cc65.git synced 2024-11-19 06:31:31 +00:00
cc65/libsrc/pet/joy/pet-ptvjoy.s
Oliver Schmidt 2c975d3642 Create static drivers directly from source files.
Up to now static drivers were created via co65 from dynamic drivers. However there was an issue with that approach:

The dynamic drivers are "o65 simple files" which obligates that they start with the 'code' segment. However dynamic drivers need to start with the module header - which is written to. For dynamic drivers this isn't more than a conceptual issue because they are always contain a 'data' segment and may therefore only be loaded into writable memory.

However when dynamic drivers are converted to static drivers using co65 then that issue becomes a real problem as then the 'code' segment may end up in non-writable memory - and thus writing to the module header fails.

Instead of changing the way dynamic drivers work I opted to rather make static driver creation totally independent from dynamic drivers. This allows to place the module header in the 'data' segment (see 'module.mac').
2014-06-04 23:50:18 +02:00

128 lines
3.4 KiB
ArmAsm

;
; PTV-2 Player joystick driver for the PET
;
; Stefan Haubenthal, 2005-05-25
; Groepaz/Hitmen, 2002-12-23
; obviously based on Ullrichs driver :)
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _pet_ptvjoy_joy
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Button state masks (8 values)
.byte $01 ; JOY_UP
.byte $02 ; JOY_DOWN
.byte $04 ; JOY_LEFT
.byte $08 ; JOY_RIGHT
.byte $10 ; JOY_FIRE
.byte $00 ; JOY_FIRE2 unavailable
.byte $00 ; Future expansion
.byte $00 ; Future expansion
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READ
.addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 2 ; Number of joysticks we support
VIA_PRA := $E841 ; Port register A
VIA_DDRA := $E843 ; Data direction register A
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present and determine the amount of
; memory available.
; Must return an JOY_ERR_xx code in a/x.
;
INSTALL:
lda #<JOY_ERR_OK
ldx #>JOY_ERR_OK
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; COUNT: Return the total number of available joysticks in a/x.
;
COUNT:
lda #<JOY_COUNT
ldx #>JOY_COUNT
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READ: lda #%10000000 ; via port A Data-Direction
sta VIA_DDRA ; bit 7: out bit 6-0: in
tax ; Joystick number into X
bne joy2
; Read joystick 1
joy1: lda #$80 ; via port A read/write
sta VIA_PRA ; (output one at PA7)
lda VIA_PRA ; via port A read/write
and #$1f ; get bit 4-0 (PA4-PA0)
eor #$1f
rts
; Read joystick 2
joy2: lda #$00 ; via port A read/write
sta VIA_PRA ; (output zero at PA7)
lda VIA_PRA ; via port A read/write
and #$0f ; get bit 3-0 (PA3-PA0)
sta tmp1 ; joy 4 directions
lda VIA_PRA ; via port A read/write
and #%00100000 ; get bit 5 (PA5)
lsr
ora tmp1
eor #$1f
ldx #0
rts