// #LAYOUT# STD *        #TAKE
// #LAYOUT# *   KERNAL_0 #TAKE
// #LAYOUT# *   *        #IGNORE

//
// Official Kernal routine, described in:
//
// - [RG64] C64 Programmers Reference Guide   - page 296
// - [CM64] Computes Mapping the Commodore 64 - page 223/224
// - https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
//
// CPU registers that has to be preserved (see [RG64]): .X, .Y
//


// XXX cleanup: iec_cmd_open and iec_cmd_close should just do ORA and jump directly here


SECOND:

#if ROM_LAYOUT_M65

	jsr m65dos_check
	bcc_16 m65dos_second                 // branch if device is handeld by internal DOS

#endif

#if CONFIG_IEC

	// Due to OPEN/CLOSE/TKSA/SECOND command encoding, allowed channels are 0-15; it is the caller
	// responsibility, hovewer, to provide value ORed with $60
	// - https://www.lemon64.com/forum/viewtopic.php?t=57694&sid=531ba3592bcffadef2ac8b9162f2e529
	// - https://www.pagetable.com/?p=1031 (Kernal API description)

	jmp common_open_close_unlsn_second

#else

	jmp kernalerror_ILLEGAL_DEVICE_NUMBER

#endif