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/cbm610/cputc.s

@@ -12,7 +12,6 @@
         .import         PLOT
 	.import		_gotoxy
 	.import	     	popa
-	.import	     	xsize
 
 	.include     	"cbm610.inc"
 
@@ -53,7 +52,7 @@ cputdirect:
 
 advance:
         iny
-        cpy     xsize
+        cpy     #XSIZE
         bne     L3
         jsr     newline         ; new line
         ldy     #0              ; + cr
@@ -62,7 +61,7 @@ L3:     sty     CURS_X
 
 newline:
    	clc
-   	lda	xsize
+   	lda	#XSIZE
    	adc	CharPtr
    	sta     CharPtr
    	bcc	L4