Polished the mouse routines

git-svn-id: svn://svn.cc65.org/cc65/trunk@899 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/c64/mouse.s b/libsrc/c64/mouse.s
index da297475271141000651e69b9192020e5c980d4b..5886fc8c10120489f15d511d84e84e4fc516a5fd 100644 (file)
--- a/libsrc/c64/mouse.s
+++ b/libsrc/c64/mouse.s
@@ -42,13 +42,14 @@ XCORR               = SPRITE_WIDTH
 _mouse_init:
        jsr     popa                    ; Ignore type and port
 
-               ldy     OldIRQ+1                ; Already initialized?
+               lda     OldIRQ+1                ; Already initialized?
                bne     AlreadyInitialized      ; Jump if yes
 
 ; Initialize variables
 
                ldx     #0
-       stx     XPos
+       lda     #XCORR
+               sta     XPos
        stx     XPos+1
        stx     YPos
        stx     YPos+1
@@ -56,8 +57,10 @@ _mouse_init:
        stx     OldPotY
                stx     XMin
        stx     XMin+1                  ; XMin = 0
-       lda     #50                     ; ## FIXME: This is the PAL value
+       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
@@ -79,14 +82,13 @@ _mouse_init:
        lda     IRQVec+1
        sta     OldIRQ+1
 
-; Set our own IRQ vector. We cheat here to save a few bytes of code:
-; The function is expected to return a value not equal to zero on success,
-; and since we know that the high byte of the IRQ handler address is never
-; zero, we will return just this byte.
+; Set our own IRQ vector.
 
-       ldx     #<MouseIRQ
-       lda     #>MouseIRQ
-       bne     SetIRQ                  ; Branch always
+               ldx     #<MouseIRQ
+       ldy     #>MouseIRQ
+       jsr     SetIRQ                  ; Set our IRQ vector, disable sprite 0
+       lda     #1                      ; Mouse successfully initialized
+       rts
 
 AlreadyInitialized:
        lda     #0                      ; Error
@@ -98,17 +100,21 @@ AlreadyInitialized:
 ;
 
 _mouse_done:
-               ldx     OldIRQ                  ; Initialized?
-       lda     OldIRQ+1
+       ldx     OldIRQ
+               ldy     OldIRQ+1                ; Initialized?
        beq     Done                    ; Jump if no
-       ldy     #0
-       sty     OldIRQ+1                ; Reset the initialized flag
-SetIRQ:        sei                             ; Disable interrupts
+       lda     #0
+       sta     OldIRQ+1                ; Reset the initialized flag
+SetIRQ:        sei                             ; Disable interrupts
        stx     IRQVec                  ; Set the new/old vector
-       sta     IRQVec+1
-       cli                             ; Enable interrupts
+               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);