GE 68K System Benutzerhandbuch

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CPM

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D20
D20 Base

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D20 ME
D20 Base

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D20/200
CCU Base

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D20/200 ME
CCU Base

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D25

Use this command to activate a breakpoint in a section of code located within RAM.

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.

Below is usage and syntax information for this command

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 

ENTER

.

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.