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|
;
; Ullrich von Bassewitz, 2002-12-20
;
; Common functions of the joystick API.
;
.import joy_libref
.importzp ptr1
.include "joy-kernel.inc"
.include "joy-error.inc"
;----------------------------------------------------------------------------
; Variables
.bss
_joy_drv: .res 2 ; Pointer to driver
; Jump table for the driver functions.
.data
joy_vectors:
joy_install: jmp $0000
joy_uninstall: jmp $0000
joy_count: jmp $0000
joy_read: jmp $0000
; Driver header signature
.rodata
joy_sig: .byte $6A, $6F, $79, JOY_API_VERSION ; "joy", version
.code
;----------------------------------------------------------------------------
; unsigned char __fastcall__ joy_install (void* driver);
; /* Install the driver once it is loaded */
_joy_install:
sta _joy_drv
sta ptr1
stx _joy_drv+1
stx ptr1+1
; Check the driver signature
ldy #.sizeof(joy_sig)-1
@L0: lda (ptr1),y
cmp joy_sig,y
bne inv_drv
dey
bpl @L0
; Set the library reference
ldy #JOY_HDR::LIBREF
lda #<joy_libref
sta (ptr1),y
iny
lda #>joy_libref
sta (ptr1),y
; Copy the jump vectors
ldy #JOY_HDR::JUMPTAB
ldx #0
@L1: inx ; Skip the JMP opcode
jsr copy ; Copy one byte
jsr copy ; Copy one byte
cpy #(JOY_HDR::JUMPTAB + .sizeof(JOY_HDR::JUMPTAB))
bne @L1
jmp joy_install ; Call driver install routine
; Driver signature invalid
inv_drv:
lda #JOY_ERR_INV_DRIVER
ldx #0
rts
; Copy one byte from the jump vectors
copy: lda (ptr1),y
iny
sta joy_vectors,x
inx
rts
;----------------------------------------------------------------------------
; unsigned char joy_uninstall (void);
; /* Uninstall the currently loaded driver. Note: This call does not free
; ** allocated memory.
; */
_joy_uninstall:
jsr joy_uninstall ; Call the driver routine
_joy_clear_ptr: ; External entry point
lda #0
sta _joy_drv
sta _joy_drv+1 ; Clear the driver pointer
tax ; Return zero
rts
|
