33 lines
740 B
ArmAsm
33 lines
740 B
ArmAsm
|
|
;;
|
|
;; Official Kernal routine, described in:
|
|
;;
|
|
;; - [RG64] C64 Programmer's Reference Guide - page 301/302
|
|
;; - [CM64] Compute's Mapping the Commodore 64 - page 223
|
|
;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
|
|
;; - http://www.zimmers.net/anonftp/pub/cbm/programming/serial-bus.pdf
|
|
;;
|
|
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
|
|
;;
|
|
|
|
|
|
talk:
|
|
|
|
;; According to serial-bus.pdf (page 15) this routine flushes the IEC out buffer
|
|
jsr iec_tx_flush
|
|
|
|
;; Check whether device number is correct
|
|
jsr iec_check_devnum
|
|
bcc +
|
|
jmp kernalerror_DEVICE_NOT_FOUND
|
|
*
|
|
;; Encode and execute the command
|
|
ora #$40
|
|
|
|
common_talk_listen: ; common part of TALK and LISTEN
|
|
|
|
sta IEC_TMP2
|
|
jmp iec_tx_command
|
|
|
|
|