Make screensize() fetch the values dynamically instead of using variables

that are set on startup. This is needed to support the C128, which can switch
the screen size at runtime.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2042 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/apple2/_scrsize.s

@@ -4,12 +4,15 @@
 ; Screen size variables
 ;
 
-	.export		xsize, ysize
+	.export	      	screensize
 
-.rodata
+        .include        "apple2.inc"
 
-xsize: 	.byte	40
-ysize:	.byte	24
+.proc   screensize
 
+        ldx     #XSIZE
+        ldy     #YSIZE
+        rts
 
+.endproc
 

libsrc/apple2/apple2.inc

@@ -20,6 +20,12 @@ MEMSIZE	=	$73		; Highest free RAM location
 BRKVec  =       $03F0           ; Break vector
 RESTOR	=	$03D0           ; Goto Dos
 
+; ---------------------------------------------------------------------------
+; Screen size
+
+XSIZE           = 40
+YSIZE           = 24
+
 ;-----------------------------------------------------------------------------
 ; Hardware