bdi
GDB
for GNU Debugger, BDI2000 (ARM)
User Manual
29
© Copyright 1997-2005 by ABATRON AG Switzerland
V 1.17
BREAKMODE mode [opc]This parameter defines how breakpoints are implemented and optional
the GDB breakpoint opcode (See also 3.3.3 Breakpoint Handling).
mode = SOFT This is the normal mode. Breakpoints are implemented
by replacing code with a special pattern.
mode = HARDIn this mode, the breakpoint hardware is used. Only 2
breakpoints at a time are supported.
opc
The BDI needs to know which opcode GDB uses to set
a breakpoint. By default a pattern of 0xE7FFDEFE is as-
sumed. If a GDB build uses a different pattern the cor-
rect opcode patter has to be specified here. If your GDB
version supports Z-packets then it is recommended to
define the pattern 0xDFFFDFFF. This pattern allows to
debug mixed ARM/Thumb applications.
Note: For ARM9E cores, the BKPT instruction is always
used for software breakpoints.
Example: BREAKMODE
HARD
BREAKMODE SOFT 0xdfffdfff
STEPMODE mode
This parameter defines how single step (instruction step) is implemented.
The alternate step mode (HWBP) may be useful when stepping instruc-
tions should not enter exception handling.
JTAG
This is the default mode. For ARM9 targets, the JTAG
single step feature is used. For ARM7 targets, a range
breakpoint that excludes the current instruction is used.
HWBP
In this mode, a hardware breakpoint on the next instruc-
tion(s) is used to implement single stepping.
Example: STEPMODE
HWBP
WORKSPACE address
If a workspace is defined, the BDI uses a faster download mode via the
ARM’s Debugger Communications Channel (DCC). The workspace is
used for a short code sequence that reads from the DDC and writes to
memory. There must be at least 32 bytes of RAM available for this code.
There is no handshake between the BDI and the code consuming the data
transferred via DCC. If the helper code on the target executes to slow, this
download mode may fail and you have to disable it.
address
the address of the RAM area
Example:
WORKSPACE 0x00000020