Normally, the Port_B_Data or Port_A_Data address is used to directly access RR8 or WR8, but setting the register pointer in Port_B_Cmd or Port_A_Cmd to RR8/WR8 is another option.
Update write_regs[WR8] and read_regs[RR8] for possible debugging purposes.
Update write_regs[WR9] even though most or all of the bits are in master_int_cntrl.
Fix hardware reset for WR9. It's supposed to leave WR9_NO_VECTOR | WR9_VECTOR_INCLUDES_STATUS unchanged.
Fix channel reset for WR9. It's supposed to clear WR9_INTERRUPT_MASKING_WITHOUT_INTACK.
With the option --serial_backend=socket, input and output to a serial port will use a SOCK_STREAM type UNIX domain socket. This allows you to do Open Firmware in one window, while the first window can be used for dingusppc debugger.
Other fixes:
- Added SIGTERM handler so that if the user force quits dingusppc, the terminal settings are properly restored. A user needs to force quit when --serial_backend=stdio and Open Firmware is taking input from ttya. If terminal settings are not restored, then running dingusppc after a force quit will cause Control-C to not work when --serial_backend is not stdio.
- Added a couple numbers to rcv_char_available - 15 is the number of consecutive characters that can processed. 400 is the total number of calls to rcv_char_available after 15 consecutive characters have been read before additional characters can be read. This delay in processing additional characters allows pasting arbitrarily large amounts of text into Open Firmware. A real serial port terminal app might have a text pacing option to limit the number of output characters per second but that is not an option since the emulator is not limiting character data to a baud rate.
Related Notes:
The socket file is created when dingusppc starts.
The socket file is named dingusppcsocket and is created in the current working directory (usually where the executable is located and where the dingusppc.log, nvram.bin, and pram.bin files are created).
The socket file is not visible in the Finder. You can see it in the terminal using the ls command.
The socket file can be used with the following command in a new terminal window:
socat UNIX-CLIENT:dingussocket -,cs8,parenb=0,echo=0,icanon=0,isig=0,icrnl=0
When dingusppc quits, the socat command ends.
Other notes:
The dingusppc --debugger option causes dingusppc to enter the debugger before Open Firmware outputs anything. You can connect to the socket while dingusppc is in the debugger. Then enter the go command to leave the debugger and start Open Firmware. However, since the startup sound takes a long time, you can probably connect to the socket before Open Firmware starts even without the --debugger option. It's like with a real Power Mac - you have a few seconds to hold Command-Option-O-F except in this case you have a few seconds to press the up arrow and press enter (for executing the last command from the terminal command history) and if you do it too late you'll still get into Open Firmware if auto-boot? was previously set to false using the dingusppc debugger which is actually the only way to get into Open Firmware since a keyboard is currently not emulated?).
To set ttya as the input and output device in Open Firmware, you can use the setenv command in the dingusppc debugger. The device path needs to be longer than the current device path (because code for handling shortening of the paths is currently not implemented). For example, ttya can replace kbd for the input-device, but to replace screen for the output-device you need to add some extra characters like this: ttya,11 (I think the number is for baud but we're not using a real serial port so baud doesn't matter).
Future ideas:
- Have dingusppc execute the socat command for you so that it opens a terminal window before Open Firmware starts.
- Add another --serial_backend for the printer port (ttyb) since now we have more than one type of serial backend. If both serial ports use socket backend, then a different name for the second socket is required.
- Have an option to make dingusppc block until something connects to the socket (this means calling accept after listen instead of after select).
- Test compatibility with serial port socket created by Parallels Desktop virtual machines in macOS.
- Find a solution that works with Windows.
- Test with Linux.
- Create a serial_backend type for tty devices. I suppose maybe socat can pipe the file socket to tty but a direct connection might be easier to setup.
- Allow using a socket created by some other app (for example, socat UNIX-LISTEN). This means dingusppc will assume the client role and will call connect instead of accept.
