Db - Define Breakpoint - GE 68K System User Manual

68K System Monitor
User's Guide

DB - Define Breakpoint

þ
CPM
Platform
Use this command to activate a breakpoint in a section of code located within RAM.
Description
At the specified address, the command saves 68000 family instruction in the
breakpoint table and replaces it with a TRAP instruction. When a process reaches the
TRAP instruction, it traps into a breakpoint handling routine, which displays a
message indicating that it encountered a breakpoint.
The 68K Monitor allows up to ten active breakpoints.
Syntax Below is usage and syntax information for this command
Command Format
Variables
Parameters
Example
Special
Considerations
General
Full Release
þ o
D20 D20 ME
D20 Base D20 Base
db address [#loops]
None
address = hexadecimal address for the breakpoint.
#loops = number of times to execute the specified address
(in decimal) before stopping; default is zero
Type db 103648 and press
This defines a breakpoint at hexadecimal address 103648,
which stops before the first execution of the instruction at that
address.
Results: The system responds with the breakpoint number
assigned to this breakpoint and the prompt. Each time
it encounters the breakpoint, the system displays the
breakpoint number, loop count, and register values. If
the loop count is greater than zero, it is decremented.
Otherwise, the process is suspended.
You may define only one breakpoint at a single address, to a
maximum of ten breakpoints per system. An attempt to define
a breakpoint in read only or non-existent memory results in a
bus error.
SWM0023-1.00 -2
o þ
D20/200 D20/200 ME
CCU Base CCU Base
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ENTER
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D25
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