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/kbhit.s

@@ -1,16 +1,23 @@
 ;
-; Ullrich von Bassewitz, 06.08.1998
+; Ullrich von Bassewitz, 2003-12-20
 ;
 ; int kbhit (void);
 ;
 
 	.export		_kbhit
+
+        .importzp       sysp0
 	.import		return0, return1
 
 	.include	"cbm610.inc"
 
 .proc	_kbhit
-	lda	KeyIndex      	; Get number of characters
+        ldx     IndReg
+        lda     #$0F
+        sta     IndReg
+        ldy     #$D1            ; Number of keys in kbd buffer
+        lda     (sysp0),y
+        stx     IndReg
 	bne   	L1
 	jmp	return0
 L1:	jmp	return1