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T
3.30 TRACE
T [<count>]
Use the T command to execute one instruction at a time and display the target state after
execution. T starts tracing at the address in the target PC. The optional count field specifies the
number of instructions to be traced before returning control to CPU32Bug. The count field
default is 1. As each instruction is traced, a register display printout is generated.
During tracing, breakpoints in ROM or write protected memory are monitored (but not inserted)
for all trace commands which allow the use of breakpoints in ROM or write protected memory.
Control is returned to CPU32Bug if a breakpoint with 0 count is encountered.
Trace functions are implemented with the trace bits (T0, T1) in the MCU device status register.
Do not modify trace bits (T0, T1) while using the trace commands. Because the trace functions
are implemented using the hardware trace bits in the MCU, code in ROM can be traced. During
trace mode, breakpoints are monitored and their counts decremented when the corresponding
instruction with breakpoint is traced. This allows breakpoints to work in ROM, but only in the
trace mode.
EXAMPLE
The following program resides at location $7000.
CPU32Bug>MD 7000;DI<CR>
00007000 2200
00007002 4282
00007004 D401
00007006 E289
00007008 66FA
0000700A E20A
0000700C 55C2
0000700E 60FE
CPU32Bug>
Initialize PC and D0:
CPU32Bug>RM PC<CR>
PC
=00008000 ? 7000.<CR>
CPU32Bug>RM D0 <CR>
D0
=00000000 ? 8F4IC.<CR>
M68CPU32BUG/D REV 1
Trace
MOVE.L
D0,D1
CLR.L
D2
ADD.B
D1,D2
LSR.L
#$1,D1
BNE.B
$7004
LSR.B
#$1,D2
SCS.B
D2
BRA.B
$700E
3-60
DEBUG MONITOR COMMANDS
T
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