Technical data

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172Bug Firmware
3
172Bug includes:
❏ Commands for display and modification of memory
❏ Breakpoint and tracing capabilities
❏ A powerful assembler/disassembler useful for patching programs
❏ A “self-test at power-up” feature which verifies the integrity of the
system
In addition, the TRAP #15 system calls make various 172Bug routines that
handle I/O, data conversion, and string functions available to user
programs.
172Bug consists of three parts:
❏ A command-driven user-interactive software debugger, described
in this chapter. It is referred to here as “the debugger” or “172Bug”.
❏ A command-driven diagnostic package for the MVME172LX
hardware, referred to here as “the diagnostics”.
❏ A user interface or debug/diagnostics monitor that accepts
commands from the system console terminal.
When using 172Bug, you operate out of either the debugger directory or
the diagnostic directory.
❏ If you are in the debugger directory, the debugger prompt 172-Bug>
is displayed and you have all of the debugger commands at your
disposal.
❏ If you are in the diagnostic directory, the diagnostic prompt 172-
Diag> is displayed and you have all of the diagnostic commands at
your disposal as well as all of the debugger commands.
Because 172Bug is command-driven, it performs its various operations in
response to user commands entered at the keyboard. When you enter a
command, 172Bug executes the command and the prompt reappears.
However, if you enter a command that causes execution of user target code
(for example, GO), then control may or may not return to 172Bug,
depending on the outcome of the user program.