;;
;; Official Kernal routine, described in:
;;
;; - [RG64] C64 Programmer's Reference Guide   - page 302
;; - [CM64] Compute's Mapping the Commodore 64 - page 224
;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;


tksa:

	;; Due to TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
	;; allowed channels are 0-15; report error if out of range
	cmp #$10
	bcs kernalerror_FILE_NOT_INPUT

	ora #$F0
	sta BSOUR
	jsr iec_tx_command
	bcs + ; branch if error
	;; XXX - is it really the right place to do a turnaround? I've got some doubts
	;; (it forces us to send the TKSA command 'manually' sometimes), but
	;; Luigi Di Fraia (https://luigidifraia.wordpress.com/2017/06/27/codebase64-on-the-kernal-behaviour/)
	;; claims TKSA Kernal routine actually does the turnaround
	jmp iec_turnaround_to_listen
*
	rts