SwTPc logoS-Bug Monitor ROM

In a 2K EPROM residing at addresses $F800 to $FFFF lives the S-Bug monitor program. In most machines, its main purpose in life is to hold the boot program, which knows just enough about the disk drive to read its boot sector, which in turn is smart enough to load an operating system. It also necessarily has subroutines for simple I/O, which may (or may not) be used by whatever O/S is loaded.

However, it can be used without any O/S or disk drives, letting you examine and alter the contents of memory and run machine-code, "programming on the bare metal". This was important in the good old days, since not every hobbyist could afford disk drives.

      Examine/change registers: ^A ^B ^C ^D ^P ^U ^X ^Y
      Others: B D E G L M P Q R S U X

Coming soon: command syntax and summaries

(remove all "x"s to get a valid address)