System Debug Reference Manual (32650-90888)
112 Chapter4
System Debug Command Specifications :-Exit
DATAB
Data breakpoints "break" when the indicated address is written to. The debugger stops at
the instruction that is about to perform the write operation.
The DATAB command is used to set process-local and global (system-wide) data
breakpoints.
Setting a breakpoint for another process is implemented so that it appears the target
process set the breakpoint itself. Therefore, when the target process encounters the
breakpoint, it enters Debug with its output directed to the LDEV associated with that
process.
Parameters
virtaddr
The virtual address at which to set the data breakpoint.
Virtaddr
can be a short pointer, a long pointer, or a full logical code
pointer.
pin
|
@
The process identification number (PIN) of the process for which the
breakpoint is to be set. If omitted, the breakpoint is set for the current
process. The character "@" can be used to set a global breakpoint at which
all processes stop.
byte_count Byte_count
specifies the number of bytes to "protect" with the data
breakpoint. If no value is given, one byte is assumed.
count Count
has a twofold meaning: it specifies to break every
n
th time the
breakpoint is encountered, and it is used to set permanent/temporary
breakpoints.
count
is positive, the breakpoint is permanent. If
count
is negative, the
breakpoint is temporary and is deleted as soon as the process attempts to
modify the protected address. For example, a
count
of 4 means break
every fourth time the protected address range is modified; a
count
of -4
means break on the fourth time, and immediately delete the breakpoint. If
count
is omitted, +1 is used, which breaks every time the address range is
written to, permanently.
loudness
Either LOUD or QUIET.IfQUIET is selected the debugger does not print out
a message that the breakpoint has been hit. This is useful for performing a
command list a great number of times before stopping without being
inundated with screen after screen of breakpoint messages. These
keywords may be abbreviated as desired. The default value is LOUD.
cmdlist
A single Debug command or a list of Debug commands that are executed
immediately when the breakpoint is encountered. Command lists for
breakpoints are limited to 80 characters. (If this is too few characters,
write a macro and have the command list invoke the macro).
Cmdlist
has
the form:
CMD1
{ CMD1; CMD2; CMD3; ... }