Updated the mouse module

git-svn-id: svn://svn.cc65.org/cc65/trunk@440 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/c64/mouse.s b/libsrc/c64/mouse.s
index 206901e7cb1ea69ea6d13f3adb19e35b58c27734..64c442865d214b3cb3f6d15a6e49cf4fa08febc8 100644 (file)
--- a/libsrc/c64/mouse.s
+++ b/libsrc/c64/mouse.s
@@ -9,8 +9,9 @@
        .export         _mouse_hide, _mouse_show
        .export         _mouse_box, _mouse_info
        .export         _mouse_x, _mouse_y
-       .export         _mouse_move
-
+       .export         _mouse_move, _mouse_buttons
+                                                  
+       .import         _readjoy
                .import         popa, popsreg, addysp1
        .importzp       sp, sreg
 
@@ -22,7 +23,9 @@
 
 ; --------------------------------------------------------------------------
 ;
-; void __fastcall__ mouse_init (unsigned char port, unsigned char sprite, unsigned char type);
+; unsigned char __fastcall__ mouse_init (unsigned char port,
+;                                       unsigned char sprite,
+;                                       unsigned char type);
 ;
 
 _mouse_init:
@@ -31,7 +34,7 @@ _mouse_init:
        jsr     popa                    ; Get the port number
 
                ldy     OldIRQ+1                ; Already initialized?
-               bne     Done                    ; Jump if yes
+               bne     AlreadyInitialized      ; Jump if yes
 
        stx     MouseSprite             ; Remember the sprite number
        sta     MousePort               ; Remember the port number
@@ -66,11 +69,18 @@ _mouse_init:
        lda     IRQVec+1
        sta     OldIRQ+1
 
-; Set our own IRQ vector
+; 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
+; zweo, we will return just this byte.
+
+       ldx     #<MouseIRQ
+       lda     #>MouseIRQ
+       bne     SetIRQ                  ; Branch always
 
-       lda     #<MouseIRQ
-       ldx     #>MouseIRQ
-       bne     SetIRQ
+AlreadyInitialized:
+       lda     #0                      ; Error
+       rts
 
 ; --------------------------------------------------------------------------
 ;
@@ -78,14 +88,14 @@ _mouse_init:
 ;
 
 _mouse_done:
-               lda     OldIRQ                  ; Initialized?
-       ldx     OldIRQ+1
-       beq     Done                    ; Jump if no
+               ldx     OldIRQ                  ; Initialized?
+       lda     OldIRQ+1
+       beq     Done                    ; Jump if no
        ldy     #0
        sty     OldIRQ+1                ; Reset the initialized flag
 SetIRQ:        sei                             ; Disable interrupts
-       sta     IRQVec                  ; Set the new/old vector
-       stx     IRQVec+1
+       stx     IRQVec                  ; Set the new/old vector
+       sta     IRQVec+1
        cli                             ; Enable interrupts
 Done:  rts
 
@@ -229,6 +239,16 @@ _mouse_move:
 @L9:   cli                             ; Enable interrupts
        rts
 
+
+; --------------------------------------------------------------------------
+;
+; unsigned char mouse_buttons (void);
+;
+
+_mouse_buttons:
+       lda     MousePort               ; Get the port 
+       jmp     _readjoy                ; Same as joystick
+
 ; --------------------------------------------------------------------------
 ;
 ; Mouse interrupt handler