This is a modified version of MEGA65 Open ROMs (https://github.com/MEGA65/open-roms),
forked at upstream commit ad178dbe4d48cd6a317737a8e0e7e662f7e33d32.

Modified by Christian Werner, 2026-10-14, 2026-10-15, 2026-10-17, and 2026-10-18, for the mc64
computers of arnitech, a set of Minecraft mods (https://git.susdog.de/chris/arnitech). The
fork lives at https://git.susdog.de/chris/open-roms, branch mc64.

Changes:

- src/,,config_mc64.s: a new build configuration, copied from src/,,config_c64.s, with its
  own config ID ($6D), the brand "MC64", and BCD_SAFE_INTERRUPTS turned off.
- Makefile: targets for that configuration, build/kernal_mc64.rom and build/basic_mc64.rom,
  made the same way as the c64 ones.
- src/kernal/iec/ciout.s (2026-10-15): CIOUT buffers its byte in TBTCNT, where the send
  routine takes it from, not in BSOUR (upstream PR #113).
- src/kernal/iec/close_iec.s (2026-10-15): CLOSE sends LISTEN, $E0 plus the secondary
  address, and UNLISTEN; it sent a command ORed with zero page $E0 and no LISTEN.
- src/kernal/iec/chkin_iec.s, ckout_iec.s (2026-10-15): CHKIN and CHKOUT take the secondary
  address from SAT, not from LAT, the logical file numbers.
- src/kernal/iec/tksa.s (2026-10-15): TKSA sends the secondary address it is given, without
  ORing $90 into it (upstream issue #116).
- src/kernal/iec/iec_tx_byte.s (2026-10-15): a data byte that no listener holds DATA for
  sets ST to $80 (device not present) and returns, instead of waiting forever.
- src/kernal/iec/close_iec.s (2026-10-15): a CLOSE that finds no device sets ST to $80
  (device not present), and still frees the file number.
- src/kernal/iec/unlsn.s, untlk.s (2026-10-15): UNLSN and UNTLK end with CLK, DATA, and ATN
  released; UNLSN left CLK pulled, and UNTLK waited for a talker to pull CLK, which after
  UNTALK none does, and then left CLK pulled.
- src/kernal/iec/iec_return.s (2026-10-15): a serial routine that finds no device releases
  CLK, DATA, and ATN; it left CLK pulled.
- src/,,config_mc64.s, src/aliases/,aliases_hardware_arnitech.s, src/kernal/arnitech/
  (new), Makefile, src/kernal/init/fda3.ioinit.s, CONFIG.md (2026-10-17): a new option,
  ARNITECH_CONTROLLER, on in the mc64 configuration only. IOINIT sets CIA #1's TOD on 50 Hz
  and, if the Arnitech controller's signature is at $DE80, from the controller's clock. The
  Arnitech jump table at $FF00 wraps the controller's registers: "ARNI", a version, an entry
  count, and JMPs from $FF06 to find a Card by its type and to set the TOD.
- assets/8x8font.png (2026-10-18): the first character set draws screen code 35, '#', as the
  second does; it was blank, and its reverse (163) not its inverse.
- src/kernal/screen/chrout_to_screen_code.s (2026-10-18): CHROUT prints PETSCII $E0-$FE as
  screen codes $60-$7E and $FF (pi) as $5E, as a C64 does; it printed $A0-$BF.
- src/kernal/init/e5a0.vicii_init.s, vicii_init_registers.s (new),
  src/kernal/keyboard/e5b4.* (new), src/kernal/screen/ea24.*, ecf0.* (new),
  src/kernal/screen/screen_calculate_pnt_user.s (2026-10-18): routines at $E5B4 (take a key
  from the keyboard buffer) and $EA24 (USER from PNT), and the screen lines' low bytes at
  $ECF0, where cc65's runtime and ip65 call and read them; vicii_init's work moves out of
  $E5A0-$E5C8 to make room.
- src/,,config_mc64.s (2026-10-18): DOS_WEDGE on, TRANSCENDENTAL_FUNCTIONS off.
- src/basic/wedge/wedge_dos.s (2026-10-18): a DOS command sent with @ prints the status the
  drive gives for it; closing every file first had reset it to OK.
- src/kernal/iec/iec_tx_byte.s, iec_tx_command.s (2026-10-18): IRQs are disabled before CLK
  is released to send a byte; an IRQ in between could hide the listener's EOI
  acknowledgement and hang the transfer.
- src/aliases/,aliases_hardware_arnitech.s, src/kernal/arnitech/arnitech_net.s (new),
  src/kernal/arnitech/ff00.arnitech_jumptable.s, CONFIG.md (2026-10-18): version 2 of the
  Arnitech jump table, with JMPs from $FF0C that reset a Network Card's CS8900A at the
  RR-Net socket, copy its MAC address, and send and receive Ethernet frames through it.
- src/,,config_mc64blade.s (new), Makefile (2026-10-18): a second configuration, mc64blade,
  the Firmware of arnitech's Blades: the mc64 one with its own config ID ($6E), the brand
  "MC64 BLADE", no tape, programmable keys, joystick cursor, panic screen, or feature list, and
  ARNITECH_BLADE on; targets build/kernal_mc64blade.rom and build/basic_mc64blade.rom.
- src/aliases/,aliases_hardware_arnitech.s, src/kernal/arnitech/arnitech_terminal.s,
  arnitech_native.s, arnitech_autoboot.s (new), src/kernal/screen/*, src/kernal/keyboard/*,
  src/kernal/init/*, src/kernal/iostack/e50a.plot.s, f157.chrin.s, f1ca.chrout.s,
  src/kernal/interrupts/*, src/kernal/time/udtim.s, src/kernal/iec/iec_wait1ms.s,
  src/basic/init/basic_cold_start_internal.s, src/basic/,imports.s, CONFIG.md (2026-10-18): a
  new option, ARNITECH_BLADE, on in the mc64blade configuration only. It leaves out the screen
  editor, the keyboard matrix scan, the VIC-II set-up, PAL detection, and the Cartridge checks;
  the screen and the keyboard are an Arnitech Terminal Card, the serial bus's 1 ms wait counts
  on CIA #1's timer B, CINT puts handlers for a 65816's native-mode interrupts under the KERNAL,
  and BASIC's cold start loads and runs the first program on device 8.
- NOTICE: this file.

The licence terms are unchanged; see LICENSE, COPYING, and COPYING.LESSER.