; ; Driver for the Inkwell Systems 170-C and 184-C lightpens. ; ; 2014-04-26, Christian Groessler ; 2014-05-01, Greg King ; .include "zeropage.inc" .include "mouse-kernel.inc" .include "c128.inc" .macpack generic ; ------------------------------------------------------------------------ ; Header. Includes jump table. .segment "HEADER" 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 ; This driver is for the 40-column screen. XSIZE = 40 YSIZE = 25 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 INIT_save: .res 1 ; Keyboard buffer fill level at start of interrupt old_key_count: .res 1 ; Original IRQ vector old_irq: .res 2 .data ; Default Inkwell calibration. ; The first number is the width of the left border; ; the second number is the actual calibration value. 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: ; Disable the BASIC interpreter's interrupt-driven sprite-motion code. ; That allows direct access to the VIC-IIe's sprite registers. lda INIT_STATUS sta INIT_save lda #%11000000 sta INIT_STATUS ; Initiate some 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 ; Initiate our IRQ magic. ; Remember the ROM IRQ continuation address. ldx IRQInd+2 lda IRQInd+1 stx old_irq+1 sta old_irq lda libref ldx libref+1 sta ptr3 ; Point to mouse_adjuster stx ptr3+1 ; Set the ROM IRQ continuation address to point to the provided routine. ldy #2 lda (ptr3),y iny sei sta IRQInd+1 lda (ptr3),y sta IRQInd+2 ; Set the address of our IRQ callback routine. ; Because it's called via "rts", we must use "address-1". iny lda #<(callback-1) sta (ptr3),y iny lda #>(callback-1) sta (ptr3),y ; Set the ROM entry-point vector. ; Because it's called via "rts", we must decrement it by one. iny lda old_irq sub #<1 sta (ptr3),y iny lda old_irq+1 sbc #>1 sta (ptr3),y cli ; Call a calibration function through the library-reference. ldy #1 lda (ptr3),y bze @L1 ; Don't call pointer if it's NULL sta Calibrate+2 ; Point to function dey lda (ptr3),y sta Calibrate+1 lda #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: lda old_irq ldx old_irq+1 sei sta IRQInd+1 stx IRQInd+2 ;cli ; This will be done at end of HIDE jsr HIDE ; Hide cursor on exit lda INIT_save sta INIT_STATUS rts ;---------------------------------------------------------------------------- ; 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 #>0 ; 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 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 lda KEY_COUNT sta old_key_count ; 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 #%01111111 ; (Keyboard scan leaves this in port A) ;sta CIA1_PRA 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 ; Read the VIC-II lightpen registers. 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 #>0 ; 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 #>0 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 .define OLD_BUTTONS Buttons ; Tells callback.inc where the old port status is stored .include "callback.inc"