Patches by Greg King to avoid crosstalk between mouse and keyboard.

[cc65] / libsrc / c64 / c64-joymouse.s

diff --git a/libsrc/c64/c64-joymouse.s b/libsrc/c64/c64-joymouse.s
index b264bacef1464f0ac8bec4238a4b92188bcea520..e99adac7a2497730a2d19720b676b5f05c3eeec5 100644 (file)
--- a/libsrc/c64/c64-joymouse.s
+++ b/libsrc/c64/c64-joymouse.s
@@ -2,6 +2,7 @@
 ; Driver for a "joystick mouse".
 ;
 ; Ullrich von Bassewitz, 2004-03-29, 2009-09-26
+; 2010-02-08, Greg King
 ;
 
         .include        "zeropage.inc"
@@ -193,14 +194,12 @@ GETBOX: sta     ptr1
         stx     ptr1+1                  ; Save data pointer
 
         ldy     #.sizeof (MOUSE_BOX)-1
-        sei
 
 @L1:    lda     XMin,y
         sta     (ptr1),y
         dey
         bpl     @L1
 
-        cli
                rts
 
 ;----------------------------------------------------------------------------
@@ -297,12 +296,18 @@ IOCTL:  lda     #<MOUSE_ERR_INV_IOCTL     ; We don't support ioclts for now
 ; MUST return carry clear.
 ;
 
-IRQ:   lda     #$7F
-       sta     CIA1_PRA
-       lda     CIA1_PRB                ; Read joystick #0
-        and     #$1F
-       eor     #$1F                    ; Make all bits active high
-        sta     Temp
+; Avoid crosstalk between the keyboard and a joystick.
+
+IRQ:   ldy     #%00000000              ; Set ports A and B to input
+       sty     CIA1_DDRB
+       sty     CIA1_DDRA               ; Keyboard won't look like joystick
+       lda     CIA1_PRB                ; Read Control-Port 1
+       dec     CIA1_DDRA               ; Set port A back to output
+       eor     #%11111111              ; Bit goes up when switch goes down
+       beq     @Save                   ;(bze)
+       dec     CIA1_DDRB               ; Joystick won't look like keyboard
+       sty     CIA1_PRB                ; Set "all keys pushed"
+@Save:  sta     Temp
 
 ; Check for a pressed button and place the result into Buttons