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

31 lines
742 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:
#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)
ora #$90
jmp common_untlk_tksa
#else
jmp kernalerror_ILLEGAL_DEVICE_NUMBER
#endif