Files
open-roms/c64/kernal/tksa.s
T

27 lines
633 B
ArmAsm

;;
;; 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 OPEN/CLOSE/TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
;; allowed channels are 0-15; report error if out of range
cmp #$10
bcc +
jmp kernalerror_DEVICE_NOT_FOUND ; XXX find a better error message for wrong channel (create new one?)
*
ora #$F0
jmp common_untlk_tksa