* Programmed I/O: READ
* ==============  ^^^^
* CPU is doing the I/O operation...
* - basically, the CPU runs a program that achieves transfer of
* - the data from I/O device <--> memory
*

* I/O device is termin0 (keyboard), memory mapped as follows:
*
*    $1400 = command register - 0 = read, 1 = write
*    $1404 = length register 
*    $1408 = address register
*    $140C = status register 
*
	xdef start, stop
	xdef buf, len

start:
        move.l #-1, $140C       ; Clobber status
        move.l #buf, $1408      ; Set buffer address
        move.l #0, $1400;       ; Read

* -------------------------------------------- Now termin0 is reading from file

rloop:  cmpi.l #-1, $140c       ; Test if status is still -1
        beq         rloop       ; Repeat testing until status changes

* ------------------------------ Now termin0 has transfered one line to `buf'

normal: move.l $1404, len        ; get length of string read

stop:   bra stop

buf:    ds.b 80
len:    ds.l 1

        end