Using the Debugger
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5-3
5
Using the Debugger
PPCBug is command-driven; it performs its various operations in response
to commands that you enter at the keyboard. When the
PPC1-Bug
prompt
appears on the screen, the debugger is ready to accept debugger
commands. When the
PPC1-Diag
prompt appears on the screen, the
debugger is ready to accept diagnostics commands. To switch from one
mode to the other, enter SD.
What you key in is stored in an internal buffer. Execution begins only after
you press the Return or Enter key. This allows you to correct entry errors,
if necessary, with the control characters described in the PPCBug
Firmware Package User’s Manual.
After the debugger executes the command, the prompt reappears.
However, if the command causes execution of user target code (for
example, GO) then control may or may not return to the debugger,
depending on what the user program does. For example, if a breakpoint has
been specified, then control returns to the debugger when the breakpoint is
encountered during execution of the user program. Alternately, the user
program could return to the debugger by means of the System Call Handler
routine RETURN (described in the PPCBug Firmware Package User’s
Manual). For more about this, refer to the GD, GO, and GT command
descriptions in the PPCBug Firmware Package User’s Manual.
A debugger command is made up of the following parts:
❏
The command name, either uppercase or lowercase (for example,
MD or md).
❏
Any required arguments, as specified by command.
❏
At least one space before the first argument. Precede all other
arguments with either a space or comma.
❏
One or more options. Precede an option or a string of options with
a semicolon (;). If no option is entered, the command’s default
option conditions are used.
