Function Name: STOP

Purpose: Scan STOP key
Call address: $FFE1 (hex) 65505 (decimal)
Preparation:

	Registers:	none
	Memory:		system map
	Flags:		none
	Calls:		none

	Registers:	.A = last keyboard row
			.X = used (if STOP key)
	Memory:		none
	Flags:		status valid

Description: STOP checks a Kernal variable STKEY ($91), which is updated by UDTIM during normal IRQ processing and contains the last scan of keyboard column C7. The STOP key is bit 7, which will be 0 if the key is down. If it is, default I/O channels are restored via CLRCH and the keyboard queue is flushed by resetting NDX ($D0). The keys on keyboard line C7 are:

Bit:	7	6	5	4	3	2	1	0
Key:	STOP	Q	C=	SPACE	2	CTRL	<-	1

The path to STOP is through an indirect RAM vector at $328. Applications may therefore provide their own STOP procedures or supplement the system's by redirecting this vector to their own routine.

EXAMPLE:

	JSR	$FFE1	;scan STOP key
	BEQ	stop	;branch if down