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If you are mapping the vector table to a target ROM area and are not able to
modify location 24H, you can map the vector table area to emulation RAM,
copy the contents of your target ROM to emulation RAM, then modify
location 24H. Here are the steps needed to do this:
1
2
3
Note
The Utilities→Image... (ALT, -, U, I) command allows you map a section of
memory as emulation RAM or ROM and copy the contents of your target
memory to that section. In this example, it is used to read all locations 0
through 3FFH from your target ROM, then write those values to emulation
memory. This is a convenient way of making changes to your target ROM
without having to burn new ROMs.
If You Need Interrupts Serviced While Running in the Monitor
By default, the foreground monitor leaves the Interrupt Mask of the 68302 at
7 after a "break" into the monitor. If you wish to have any interrupts other
than level 7 interrupts serviced while the monitor is running, you must
modify the monitor source code. The monitor source has the following
instructions commented out:
Simply uncomment the instructions shown above and reassemble and relink
the monitor; then, reload your configuration.
Note that the monitor is not reentrant. This means that you should be
careful not to cause a "break" into the monitor at a time when your program
may have interrupted the monitor. An example of this would be a case where
you set a breakpoint inside one of your interrupt service routines, and that
interrupt service routine gets called as a result of an interrupt to the monitor
program.
Map 0 through 3FFH as emulation RAM.
From the Memory window's control menu, choose the Utilities→Image...
(ALT, -, U, I) command. Enter a start address of 0, an end address of
03ffh, and choose the OK button.
Modify the long word of memory at address 24H to the address of
TRACE_ENTRY.
;
MOVE.W
;
OR
;
MOVE.W
;
AND
;
MOVE.W
Chapter 4: Plugging the Emulator into Target Systems
Configuring the Emulator for In-Circuit Operation
PSTAT,D0
#0F8FFH,D0
SR,D1
D1,D0
D0,SR
111
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