6800     EXORsim

EXORsim

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EXORsim simulates a Motorola EXORciser, which was a development system that Motorola sold in the late 1970s and early 1980s for the 8-bit 6800 microprocessor. Some pictures of this development system can be found at Pekka Tanskanen's website here.

EXORsim also simulates a SWTPC 6800 Computer System, which allows you to run the TSC FLEX operating system.

EXORsim provides these features:

  • Linux or Cygwin console-based emulation allows you to use terminal emulator features such as scroll-back. I find this to be more useful than some emulators which run under MS-Windows, but provide only a very rudimentary terimnal.
  • Simulates 6800 CPU and the following peripherals:
    • ACIA serial port.
    • Line printer port.
    • Floppy disk controller:
      • EXORdisk-II floppy diskette controller emulated by intercepting calls to the controller ROM
      • FD1771 hardware emulation for MF68 with DC_1 controller floppy drive
  • Provides a separate command, MDOS, which allows you to read and write files to MDOS diskette images.
  • Provides a stand-alone 6800 disassembler.
  • Includes a powerful debug monitor which allows you to:
    • Assemble 6800 directly to memory. The assembler is symbolic and powerful enough to assemble programs in the Motorola User's Group Library. One way is to select the entire source listing from the web-browser and paste into the monitor after starting the "a" command.
    • Disassemble memory to the screen.
    • Load and save Motorola S19 files / tapes.
    • Load and save binary images.
    • Trace program execution.
    • Single step and continue until breakpoint. A trace buffer is provided, so you can see the instructions which led up to the breakpoint.
    • Call a 6800 subroutine and return to debug monitor when it returns.
    • Hex dump and memory/register modifiction.
  • The output from the disassembler and the tracing features of the debug monitor are annotated with a information from a "facts" file. For example, this file will have known hardware addresses, MDOS system calls, etc. It's not as powerful as IDA, but it works well enough for small programs.