* STEPFAST.ASM - Set step interval bits to zero. Gives 12ms step
*    interval with the 1771, 6ms with the 2797 (e.g., FD-2).
*    This only works with disk drivers that support this feature.

PSTRNG	equ	$AD1E		;FLEX display string
WARMS	equ	$AD03		;FLEX warm start
STPRATE	equ	$BEB3		;1771 step rate in disk driver

	org	$A100		;FLEX command space

stpFast	ldx	#mNotSup	;assume not supported
	ldaa	STPRATE		;see if valid rate already there
	anda	#$FC		;ignore rate bits
	bne	exit		;invalid value - wrong driver

	staa	STPRATE		;set rate bits to aero
	ldx	#mStep		;display "SET" message

exit	jsr	PSTRNG		;display message
	jmp	WARMS		;exit

* Messages

mStep	fcc	'FAST STEPPING ENABLED'
	fcb	4

mNotSup	fcc	'FAST STEPPING NOT SUPPORTED BY THIS DISK DRIVER'
	fcb	4

	end	stpFast
