mouse.s
;
; Ullrich von Bassewitz, 24.04.1999
;
; Routines for the 1351 proportional mouse. Parts of the code are from
; the Commodore 1351 mouse users guide.
;
.export _mouse_init, _mouse_done
.export _mouse_hide, _mouse_show
.export _mouse_box, _mouse_info
.export _mouse_move, _mouse_pos
.export _mouse_buttons, _mouse_info
.import _readjoy
.import popax, addysp1
.importzp ptr1, sp
.include "c64.inc"
.macpack generic
.code
; --------------------------------------------------------------------------
;
; Constants
;
SPRITE_HEIGHT = 21
SPRITE_WIDTH = 24
SCREEN_HEIGHT = 200
SCREEN_WIDTH = 320
XCORR = SPRITE_WIDTH
; --------------------------------------------------------------------------
;
; unsigned char __fastcall__ mouse_init (unsigned char type);
;
_mouse_init:
lda OldIRQ+1 ; Already initialized?
bne AlreadyInitialized ; Jump if yes
; Initialize variables
ldx #0
lda #XCORR
sta XPos
stx XPos+1
stx YPos
stx YPos+1
stx OldPotX
stx OldPotY
stx XMin
stx XMin+1 ; XMin = 0
lda #50 ; ## FIXME: This is the PAL value
sta YCorr
sta YPos
stx YPos+1
sec
sbc #SPRITE_HEIGHT ; Sprite height in pixels
sta YMin
stx YMin+1 ; YMin = 29
lda #SCREEN_HEIGHT ; Vertical screen res
add YCorr ; Add correction factor
sta YMax
stx YMax+1
inx ; X = 1
stx Invisible ; Mouse *not* visible
lda #<(SCREEN_WIDTH + SPRITE_WIDTH)
sta XMax
stx XMax+1 ; XMax = 320 + sprite width
; Remember the old IRQ vector
lda IRQVec
sta OldIRQ
lda IRQVec+1
sta OldIRQ+1
; Set our own IRQ vector.
ldx #<MouseIRQ
ldy #>MouseIRQ
jsr SetIRQ ; Set our IRQ vector, disable sprite 0
lda #1 ; Mouse successfully initialized
rts
AlreadyInitialized:
lda #0 ; Error
rts
; --------------------------------------------------------------------------
;
; void mouse_done (void);
;
_mouse_done:
ldx OldIRQ
ldy OldIRQ+1 ; Initialized?
beq Done ; Jump if no
lda #0
sta OldIRQ+1 ; Reset the initialized flag
SetIRQ: sei ; Disable interrupts
stx IRQVec ; Set the new/old vector
sty IRQVec+1
lda VIC_SPR_ENA ; Get sprite enable register
and #$FE ; Disable sprite #0
sta VIC_SPR_ENA ; Write back
cli ; Enable interrupts
Done: rts
; --------------------------------------------------------------------------
;
; void mouse_hide (void);
;
_mouse_hide:
lda Invisible ; Get the flag
bne @L1 ; Jump if already invisible
lda #$FE ; Clear bit for sprite #0
sei ; Disable interrupts
and VIC_SPR_ENA
sta VIC_SPR_ENA ; Disable sprite
cli ; Enable interrupts
@L1: inc Invisible ; Set the flag to invisible
rts
; --------------------------------------------------------------------------
;
; void mouse_show (void);
;
_mouse_show:
lda Invisible ; Mouse invisible?
beq @L1 ; Jump if no
dec Invisible ; Set the flag
bne @L1 ; Jump if still invisible
sei ; Disable interrupts
jsr MoveSprite1 ; Move the sprite to it's position
lda VIC_SPR_ENA ; Get sprite enable register
ora #$01 ; Enable sprite #0
sta VIC_SPR_ENA ; Write back
cli ; Enable interrupts
@L1: rts
; --------------------------------------------------------------------------
;
; void __fastcall__ mouse_box (int minx, int miny, int maxx, int maxy);
;
_mouse_box:
ldy #0 ; Stack offset
add YCorr ; Adjust the Y value
bcc @L1
inx
clc
@L1: sei ; Disable interrupts
sta YMax
stx YMax+1 ; maxy
lda (sp),y
adc #XCORR
sta XMax
iny
lda (sp),y
adc #$00
sta XMax+1 ; maxx
iny
lda (sp),y
add YCorr
sta YMin
iny
lda (sp),y
adc #$00
sta YMin+1 ; miny
iny
lda (sp),y
add #XCORR
sta XMin
iny
lda (sp),y
adc #$00
sta XMin+1 ; minx
cli ; Enable interrupts
jmp addysp1 ; Drop params, return
; --------------------------------------------------------------------------
;
; void __fastcall__ mouse_pos (struct mouse_pos* pos);
; /* Return the current mouse position */
;
_mouse_pos:
sta ptr1
stx ptr1+1 ; Remember the argument pointer
ldy #0 ; Structure offset
sec ; Needed for the SBC later
sei ; Disable interrupts
lda XPos ; Transfer the position
sbc #XCORR
sta (ptr1),y
lda XPos+1
sbc #$00
iny
sta (ptr1),y
lda YPos
ldx YPos+1
cli ; Restore initial interrupt state
sub YCorr ; Apply the Y correction value
bcs @L1
dex
@L1: iny
sta (ptr1),y ; Store YPos
txa
iny
sta (ptr1),y
rts ; Done
; --------------------------------------------------------------------------
;
; void __fastcall__ mouse_info (struct mouse_info* info);
; /* Return the state of the mouse buttons and the position of the mouse */
;
_mouse_info:
; 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 will just
; call _mouse_pos to initialize the struct pointer and fill the position
; fields.
jsr _mouse_pos
; Fill in the button state
jsr _mouse_buttons ; Will not touch ptr1
ldy #4
sta (ptr1),y
rts
; --------------------------------------------------------------------------
;
; void __fastcall__ mouse_move (int x, int y);
;
_mouse_move:
add YCorr ; Add Y coordinate correction
bcc @L1
inx
clc
@L1: sei
sta YPos
stx YPos+1
cli
jsr popax ; Get X
adc #XCORR ; Adjust X coordinate
bcc @L2
inx
@L2: sei
sta XPos
stx XPos+1 ; Set new position
jsr MoveSprite ; Move the sprite to the mouse pos
cli ; Enable interrupts
rts
; --------------------------------------------------------------------------
;
; unsigned char mouse_buttons (void);
;
_mouse_buttons:
lda #$00 ; Use port #0
jmp _readjoy ; Same as joystick
; --------------------------------------------------------------------------
;
; Mouse interrupt handler
;
MouseIRQ:
cld
lda SID_ADConv1 ; Get mouse X movement
ldy OldPotX
jsr MoveCheck ; Calculate movement vector
sty OldPotX
; Calculate the new X coordinate (--> a/y)
add XPos
tay ; Remember low byte
txa
adc XPos+1
tax
; Limit the X coordinate 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: sty XPos
stx XPos+1
; Calculate the Y movement vector
lda SID_ADConv2 ; Get mouse Y movement
ldy OldPotY
jsr MoveCheck ; Calculate movement
sty OldPotY
; Calculate the new Y coordinate (--> a/y)
sta OldValue
lda YPos
sub OldValue
tay
stx OldValue
lda YPos+1
sbc OldValue
tax
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: sty YPos
stx YPos+1
; Move the mouse sprite if it is enabled
jsr MoveSprite ; Move the sprite
; Jump to the next IRQ handler
jmp (OldIRQ)
; --------------------------------------------------------------------------
;
; Move check routine, called for both coordinates.
;
; Entry: y = old value of pot register
; a = current value of pot register
; Exit: y = value to use for old value
; x/a = delta value for position
;
MoveCheck:
sty OldValue
sta NewValue
ldx #$00
sub OldValue ; a = mod64 (new - old)
and #%01111111
cmp #%01000000 ; if (a > 0)
bcs @L1 ;
lsr a ; a /= 2;
beq @L2 ; if (a != 0)
ldy NewValue ; y = NewValue
rts ; return
@L1: ora #%11000000 ; else or in high order bits
cmp #$FF ; if (a != -1)
beq @L2
sec
ror a ; a /= 2
dex ; high byte = -1 (X = $FF)
ldy NewValue
rts
@L2: txa ; A = $00
rts
; --------------------------------------------------------------------------
;
; Move the mouse sprite to the current mouse position. Must be called
; with interrupts off. MoveSprite1 is an entry without checking.
;
MoveSprite:
lda Invisible ; Mouse visible?
bne MoveSpriteDone ; Jump if no
; Set the high X bit
MoveSprite1:
lda VIC_SPR_HI_X ; Get high X bits of all sprites
and #$FE ; Clear bit for sprite #0
ldy XPos+1 ; Test Y position
beq @L1
ora #$01 ; Set high X bit
@L1: sta VIC_SPR_HI_X ; Set hi X sprite values
; Set the low X byte
lda XPos
sta VIC_SPR0_X ; Set low byte
; Set the Y position
ldy YPos+1 ; Negative or too large?
bne MoveSpriteDone ; Jump if yes
lda YPos
sta VIC_SPR0_Y ; Set Y position
; Done
MoveSpriteDone:
rts
; --------------------------------------------------------------------------
; Data
.bss
OldIRQ: .res 2 ; Old IRQ vector
OldValue: .res 1 ; Temp for MoveCheck routine
NewValue: .res 1 ; Temp for MoveCheck routine
YCorr: .res 1 ; Correction for Y coordinate
Invisible: .res 1 ; Is the mouse invisible?
OldPotX: .res 1 ; Old hw counter values
OldPotY: .res 1
XPos: .res 2 ; Current mouse position, X
YPos: .res 2 ; Current mouse position, Y
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
mouse.s.html; generated on Sat Oct 13 22:41:32 2001 by ca65html
uz@cc65.org