device.aii

	include 'gsos.equ'


device_rw proc

	; inputs: a = call num
	; outputs: carry, a

	with dev_parms

	sta dev_callnum

loop
	jsl dev_dispatcher
	bcc exit
	cmp #drvr_disk_sw
	beq loop
	cmp #drvr_busy
	beq loop
	sec

exit
	rts
	endp

device_read proc export

	lda #drvr_read
	bra device_rw
	endp

device_write proc export
	lda #drvr_write
	bra device_rw
	endp


	;
	; inputs: a = block number. (1024 byte block)
	;
	;
read_data_block proc export
	with dev_parms
	; reads a data block.
	; block 0 -> all zeros (sparse support)

	cmp #0
	bne read_it

	; a = 0!
	ldy #1024-2
loop
	sta [dev_buff],y
	dey
	dey
	bpl loop

	clc
	rts

read_it
	; a = block num (1024-byte).
	; multiply x 2 for 512-byte blocks.
	asl a
	sta dev_blk_num
	lda #0
	rol a
	sta dev_blk_num+2

	lda #1024
	;sta dev_blk_size
	sta dev_req_cnt
	stz dev_req_cnt+2

	bra device_read
	endp

	end