Squeezed bytes and cycles out of the kbhit functions for almost all platforms.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4480 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/atari/kbhit.s

@@ -1,17 +1,23 @@
 ;
 ; Christian Groessler, 19-Feb-2000
 ;
-; int kbhit (void);
+; unsigned char kbhit (void);
 ;
 
 	.export		_kbhit
-	.import		return0, return1
+	.import	       	return1
 
 	.include	"atari.inc"
 
-_kbhit:
-	ldx	CH		; last pressed key
-	inx			; 255 means "no key"
-	bne	L1
-	jmp	return0
-L1:	jmp	return1
+.proc   _kbhit
+
+	ldx   	CH		; last pressed key
+	inx   			; 255 means "no key"
+	bne   	L1
+        txa                     ; X = A = 0
+        rts
+L1:	jmp   	return1
+
+.endproc
+
+