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cc65/libsrc/c64/mou/c64-inkwell.s

446 lines
13 KiB
ArmAsm

;
; Driver for the Inkwell Systems 170-C and 184-C lightpens.
;
; 2014-09-10, Greg King
;
.include "zeropage.inc"
.include "mouse-kernel.inc"
.include "c64.inc"
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table.
module_header _c64_inkwell_mou
HEADER:
; Driver signature
.byte $6d, $6f, $75 ; ASCII "mou"
.byte MOUSE_API_VERSION ; Mouse driver API version number
; Library reference
LIBREF: .addr $0000
; Jump table
.addr INSTALL
.addr UNINSTALL
.addr HIDE
.addr SHOW
.addr SETBOX
.addr GETBOX
.addr MOVE
.addr BUTTONS
.addr POS
.addr INFO
.addr IOCTL
.addr IRQ
; Mouse driver flags
.byte MOUSE_FLAG_EARLY_IRQ
; Callback table, set by the kernel before INSTALL is called.
CHIDE: jmp $0000 ; Hide the cursor
CSHOW: jmp $0000 ; Show the cursor
CPREP: jmp $0000 ; Prepare to move the cursor
CDRAW: jmp $0000 ; Draw the cursor
CMOVEX: jmp $0000 ; Move the cursor to X co-ord.
CMOVEY: jmp $0000 ; Move the cursor to Y co-ord.
;----------------------------------------------------------------------------
; Constants
SCREEN_WIDTH = XSIZE * 8
SCREEN_HEIGHT = YSIZE * 8
;----------------------------------------------------------------------------
; Global variables. The bounding box values are sorted so that they can be
; written with the least effort in the SETBOX and GETBOX routines; so, don't
; re-order them.
.rodata
; Default values for below variables
; (We use ".proc" because we want to define both a label and a scope.)
.proc DefVars
.word 0 ; XMin
.word 0 ; YMin
.word SCREEN_WIDTH - 1 ; XMax
.word SCREEN_HEIGHT - 1 ; YMax
.byte %00000000 ; Buttons
.endproc
.bss
Vars:
XMin: .res 2 ; X1 value of bounding box
YMin: .res 2 ; Y1 value of bounding box
XMax: .res 2 ; X2 value of bounding box
YMax: .res 2 ; Y2 value of bounding box
Buttons: .res 1 ; Button status bits
XPos: .res 2 ; Current lightpen position, X
YPos: .res 2 ; Current lightpen position, Y
OldPenX: .res 1 ; Previous HW-counter values
OldPenY: .res 1
.data
; Default Inkwell calibration.
; The first number is the width of the left border;
; the second number is the actual calibration value.
; See a comment below (at "Calculate the new X co-ordinate")
; for the reason for the third number.
XOffset: .byte (24 + 24) / 2 ; x-offset
; Jump to a function that puts a new calibration value into XOffset.
Calibrate: jmp $0000
.code
;----------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present.
; Must return a MOUSE_ERR_xx code in .XA.
INSTALL:
; Initiate variables. Just copy the default stuff over.
ldx #.sizeof (DefVars) - 1
@L0: lda DefVars,x
sta Vars,x
dex
bpl @L0
ldx VIC_LPEN_X
ldy VIC_LPEN_Y
stx OldPenX
sty OldPenY
; Call a calibration function through the library-reference.
lda LIBREF
ldx LIBREF+1
sta ptr1 ; Point to mouse_adjuster
stx ptr1+1
ldy #1
lda (ptr1),y
bze @L1 ; Don't call pointer if it's NULL
sta Calibrate+2 ; Point to function
dey
lda (ptr1),y
sta Calibrate+1
lda #<XOffset ; Function will set this variable
ldx #>XOffset
jsr Calibrate
; Be sure that the lightpen cursor is invisible and at the default location.
; It needs to be done here because the lightpen interrupt handler doesn't
; set the lightpen position if it hasn't changed.
@L1: sei
jsr CHIDE
lda #<(SCREEN_HEIGHT / 2)
ldx #>(SCREEN_HEIGHT / 2)
jsr MoveY
lda #<(SCREEN_WIDTH / 2)
ldx #>(SCREEN_WIDTH / 2)
jsr MoveX
cli
; Done, return zero.
lda #MOUSE_ERR_OK
tax
rts
;----------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; No return code required (the driver is removed from memory on return).
UNINSTALL := HIDE ; Hide cursor on exit
;----------------------------------------------------------------------------
; HIDE routine. Is called to hide the lightpen pointer. The mouse kernel manages
; a counter for calls to show/hide, and the driver entry point is called only
; if the mouse is currently visible, and should get hidden. For most drivers,
; no special action is required besides hiding the lightpen cursor.
; No return code required.
HIDE: sei
jsr CHIDE
cli
rts
;----------------------------------------------------------------------------
; SHOW routine. Is called to show the lightpen pointer. The mouse kernel manages
; a counter for calls to show/hide, and the driver entry point is called only
; if the mouse is currently hidden, and should become visible. For most drivers,
; no special action is required besides enabling the lightpen cursor.
; No return code required.
SHOW: sei
jsr CSHOW
cli
rts
;----------------------------------------------------------------------------
; SETBOX: Set the lightpen bounding box. The parameters are passed as they come
; from the C program, that is, a pointer to a mouse_box struct in .XA.
; No checks are done if the lightpen is currently inside the box, that is the job
; of the caller. It is not necessary to validate the parameters; trust the
; caller; and, save some code here. No return code required.
SETBOX: sta ptr1
stx ptr1+1 ; Save data pointer
ldy #.sizeof (MOUSE_BOX) - 1
sei
@L1: lda (ptr1),y
sta XMin,y
dey
bpl @L1
cli
rts
;----------------------------------------------------------------------------
; GETBOX: Return the lightpen bounding box. The parameters are passed as they
; come from the C program, that is, a pointer to a mouse_box struct in .XA.
GETBOX: sta ptr1
stx ptr1+1 ; Save data pointer
ldy #.sizeof (MOUSE_BOX) - 1
@L1: lda XMin,y
sta (ptr1),y
dey
bpl @L1
rts
;----------------------------------------------------------------------------
; MOVE: Move the mouse to a new position. The position is passed as it comes
; from the C program, that is: X on the stack and Y in .XA. The C wrapper will
; remove the parameter from the stack on return.
; No checks are done if the new position is valid (within the bounding box or
; the screen). No return code required.
;
MOVE: sei ; No interrupts
jsr MoveY
ldy #$01
lda (sp),y
tax
dey
lda (sp),y
jsr MoveX ; Move the cursor
cli ; Allow interrupts
rts
;----------------------------------------------------------------------------
; BUTTONS: Return the button mask in .XA.
BUTTONS:
lda Buttons
ldx #>$0000
; Make the lightpen buttons look like a 1351 mouse.
asl a
asl SID_ADConv2 ; PotY
rol a
eor #MOUSE_BTN_RIGHT
and #MOUSE_BTN_LEFT | MOUSE_BTN_RIGHT
rts
;----------------------------------------------------------------------------
; POS: Return the lightpen position in the MOUSE_POS struct pointed to by ptr1.
; No return code required.
POS: ldy #MOUSE_POS::XCOORD ; Structure offset
sei ; Disable interrupts
lda XPos ; Transfer the position
sta (ptr1),y
lda XPos+1
iny
sta (ptr1),y
lda YPos
iny
sta (ptr1),y
lda YPos+1
cli ; Enable interrupts
iny
sta (ptr1),y ; Store last byte
rts
;----------------------------------------------------------------------------
; INFO: Returns lightpen position and current button mask in the MOUSE_INFO
; struct pointed to by ptr1. No return code required.
;
; We're cheating here, to keep the code smaller: The first fields of the
; mouse_info struct are identical to the mouse_pos struct; so, we'll just
; call _mouse_pos to initiate the struct pointer, and fill the position
; fields.
INFO: jsr POS
; Fill in the button state
jsr BUTTONS ; Will not touch ptr1
ldy #MOUSE_INFO::BUTTONS
sta (ptr1),y
rts
;----------------------------------------------------------------------------
; IOCTL: Driver-defined entry point. The wrapper will pass a pointer to ioctl-
; specific data in ptr1, and the ioctl code in .A.
; Must return an error code in .XA.
;
IOCTL: lda #<MOUSE_ERR_INV_IOCTL ; We don't support ioctls, for now
ldx #>MOUSE_ERR_INV_IOCTL
rts
;----------------------------------------------------------------------------
; IRQ: IRQ handler entry point. Called as a subroutine, but in the IRQ context
; (so, be careful). The routine MUST return carry set if the interrupt has been
; 'handled' -- which means that the interrupt source is gone. Otherwise, it
; MUST return carry clear.
;
IRQ: jsr CPREP
; Record the state of the buttons.
; Try to avoid crosstalk between the keyboard and the lightpen.
ldy #%00000000 ; Set ports A and B to input
sty CIA1_DDRB
sty CIA1_DDRA ; Keyboard won't look like buttons
lda CIA1_PRB ; Read Control-Port 1
dec CIA1_DDRA ; Set port A back to output
eor #%11111111 ; Bit goes up when button goes down
sta Buttons
bze @L0
lda #%11101111 ; (Don't change bit that feeds VIC-II)
sta CIA1_DDRB ; Buttons won't look like keyboard
sty CIA1_PRB ; Set "all keys pushed"
; Read the VIC-II lightpen registers.
@L0: lda VIC_LPEN_Y
cmp OldPenY
; Skip processing if nothing has changed.
beq @SkipY
sta OldPenY
; Subtract the height of the top border, so that the lightpen co-ordinate
; will match the TGI co-ordinate.
sub #50
tay ; Remember low byte
ldx #>$0000
; Limit the Y co-ordinate to the bounding box.
txa
cpy YMin
sbc YMin+1
bpl @L3
ldy YMin
ldx YMin+1
jmp @L4
@L3: txa
cpy YMax
sbc YMax+1
bmi @L4
ldy YMax
ldx YMax+1
@L4: tya
jsr MoveY
@SkipY: lda VIC_LPEN_X
cmp OldPenX
; Skip processing if nothing has changed.
beq @SkipX
sta OldPenX
; Adjust the value by the calibration offset.
sub XOffset
; Calculate the new X co-ordinate.
; The VIC-II register is eight bits; but, the screen co-ordinate is nine bits.
; Therefore, the VIC-II number is doubled. Then, it points to every other pixel;
; but, it can reach across the screen.
asl a
tay ; Remember low byte
lda #>$0000
rol a
tax ; Remember high byte
; Limit the X co-ordinate to the bounding box.
cpy XMin
sbc XMin+1
bpl @L1
ldy XMin
ldx XMin+1
jmp @L2
@L1: txa
cpy XMax
sbc XMax+1
bmi @L2
ldy XMax
ldx XMax+1
@L2: tya
jsr MoveX
; Done
@SkipX: jsr CDRAW
clc ; Interrupt not "handled"
rts
; Move the lightpen pointer to the new Y pos.
MoveY: sta YPos
stx YPos+1
jmp CMOVEY
; Move the lightpen pointer to the new X pos.
MoveX: sta XPos
stx XPos+1
jmp CMOVEX