Complete redesign of the CBM610 support.

Use wrappers to call the kernal in bank 15 instead of implementing kernal
functionality within the cc65 libs (eats performance but is much smaller and
simpler).
Improved startup/shutdown code allows a return to the system bank without
calling the BASIC cold start vector.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2793 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/cbm610/crtc.s

@@ -5,7 +5,7 @@
 ;
 
  	.export	       	write_crtc, read_crtc
-	.importzp	crtc
+	.importzp	crtc, ktmp
 
 	.include      	"cbm610.inc"
 
@@ -13,7 +13,7 @@
 ; Write a value to the CRTC. The index is in Y, the value in A
 
 .proc	write_crtc
-	sta	sedt1
+	sta	ktmp
 	lda	IndReg
 	pha
 	lda	#$0F
@@ -23,23 +23,23 @@
 	sei
 	sta	(crtc),y
 	iny
-	lda	sedt1
+	lda	ktmp
 	sta	(crtc),y
 	cli
 	pla
 	sta	IndReg
-	lda	sedt1
+	lda	ktmp
 	rts
 .endproc
 
 
 .proc	read_crtc
-	sty    	sedt1
+	sty    	ktmp
 	lda	IndReg
 	pha
 	lda	#$0F
 	sta	IndReg
-	lda    	sedt1
+	lda    	ktmp
 	ldy	#$00
 	sei
 	sta	(crtc),y
@@ -50,7 +50,7 @@
 	pla
 	sta	IndReg
 	tya
-	ldy    	sedt1
+	ldy    	ktmp
 	rts
 .endproc