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cc65/libsrc/pce/joy/pce-stdjoy.s
2023-02-26 20:03:41 +01:00

144 lines
3.0 KiB
ArmAsm

;
; Standard joystick driver for the PCEngine
;
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "pce.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _pce_stdjoy_joy
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READJOY
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 4 ; Number of joysticks we support
.bss
padbuffer: .res JOY_COUNT
.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 a JOY_ERR_xx code in a/x.
;
INSTALL:
lda #JOY_ERR_OK
.assert JOY_ERR_OK = 0, error
tax
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; DEINSTALL 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.
;
;unsigned char __fastcall__ joy_count (void);
COUNT:
lda #<JOY_COUNT
clx ; ldx #>JOY_COUNT
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
;unsigned char __fastcall__ joy_read (unsigned char joystick);
READJOY:
pha
jsr read_joy
pla
tax ; Joystick number into X
; return value from buffer
joy1:
lda padbuffer,x
rts
read_joy:
; Reset Multitap counter.
lda #$01
sta JOY_CTRL
pha
pla
nop
nop
lda #$03
sta JOY_CTRL
pha
pla
nop
nop
cly
nextpad:
lda #$01
sta JOY_CTRL ; sel = 1
pha
pla
nop ; some delay is required
nop
lda JOY_CTRL
asl a
asl a
asl a
asl a
sta padbuffer,y ; store new value
stz JOY_CTRL
pha
pla
nop ; some delay is required
nop
lda JOY_CTRL
and #$0F
ora padbuffer,y ; second half of new value
eor #$FF
sta padbuffer,y ; store new value
iny
cpy #.sizeof(padbuffer)
bcc nextpad
rts