Using Cpu32Bug Target Vector Table - Motorola M68CPU32BUG User Manual

EXAMPLE
CPU32Bug>RD<CR>
PC =00003000
SFC =5=SD
D0 =00000000
D4 =00000000
A0 =00000000
A4 =00000000
00003000 203900100000
CPU32Bug>T<CR>
PC =00003006
SFC =5=SD
D0 =12345678
D4 =00000000
A0 =00000000
A4 =00000000
00003006 D280
CPU32Bug>
Notice that the value of the target stack pointer register (A7) has not changed even though a trace
exception has taken place. The user program may use the exception vector table provided by
CPU32Bug or it may create a separate exception vector table of its own.

2.5.2.1 Using CPU32Bug Target Vector Table

CPU32Bug initializes and maintains a vector table area for target programs. A target program is
any user program started by the CPU32Bug with GO or Trace commands. The starting address of
this target-vector table area is the base address of the BCC, described in paragraph 1.6. This
address is loaded into the target-state-vector base register at power-up or during a cold-start reset.
For verification use the RD command immediately after power-up to display the target-state
registers.
CPU32Bug loads the target-vector table with the debugger vectors (listed in Table 2-2) and the
other vector locations with the address of a generalized exception handler (refer to paragraph
2.5.2.3). The target program allocates as many vectors as required by simply writing its own
exception vectors into the table. If the vector locations listed in Table 2-2 are over-written, then
the accompanying debugger functions will be lost.
CPU32Bug maintains a separate vector table for its own use in a 1k byte space in the reserved
memory space. The debugger vector table is completely transparent to the user and no
modifications should ever be made to it.
M68CPU32BUG/D REV 1
Trace one instruction using debugger.
SR =2700=TR:OFF_S_7_.....
DFC =5=SD
D1 =00000000
D5 =00000000
A1 =00000000
A5 =00000000
SR =2700=TR:OFF_S_7_.....
DFC =5=SD
D1 =00000000
D5 =00000000
A1 =00000000
A5 =00000000
ADD.L
USP =00003830
D2 =00000000
D6 =00000000
A2 =00000000
A6 =00000000
MOVE.L ($100000).L,D0
USP =00003830
D2 =00000000
D6 =00000000
A2 =00000000
A6 =00000000
D0,D1
2-9
DEBUG MONITOR DESCRIPTION
VBR =00000000
SSP* =00004000
D3 =00000000
D7 =00000000
A3 =00000000
A7 =00004000
VBR =00000000
SSP* =00004000
D3 =00000000
D7 =00000000
A3 =00000000
A7 =00004000