HP 3000 Manuals

HP Transact Reference Manual

DATA BREAK REGISTER 

Sets a breakpoint at the specified register.

Syntax 

{DATA BREAK REGISTER} register [,count [,{cmdlist}]]
{DBR                }
Parameters 

register         The name of the Transact/iX register at which you want
                 the data breakpoint set.  Breakpoints can be set at the
                 input, key, match, status, statusin, or update
                 registers.  When a register value changes, a data
                 breakpoint occurs and control returns to TRANDEBUG.

count            A number indicating how often you want to stop at the
                 data breakpoint, that is, every n times it is reached.
                 The default for this parameter is 1.  To stop at a data
                 breakpoint every third time the register changes in
                 value, specify 3 for count.

cmdlst           A set of commands executed every time the breakpoint is
                 reached.  The cmdlist parameter must consist of valid
                 TRANDEBUG commands separated by semicolons.  It
                 cannot consist of NMDEBUG commands.  For example,
                 {AUTORPT;STEP;;;;MODIFY STATUS -15;CONTINUE}.  (Each of
                 the semicolons following STEP acts like a carriage
                 return if AUTORPT is turned on.)  The entire DATA BREAK
                 REGISTER command, including the cmdlst parameter, can be
                 up to 80 characters long.

Discussion 

This command allows you to set a data breakpoint at a specified register.
Any time the register value changes, a data breakpoint occurs, and the
control returns to TRANDEBUG. This command determines which instruction
is modifying a specified register.  The data breakpoint always occurs at
the instruction after the one that modified the register.

To determine the specific instruction that modified the value, just look
at the instruction previous to the current one.  If the data breakpoint
is successfully set, a message is displayed showing information about the
breakpoint.  You can only set register breakpoints in the current system.

Example 

The following example shows how to set data breakpoints at registers.

     TRANDEBUG> data break register match,,{DISPLAY MATCH} 

                  DATA BREAKPOINT SET:

                    SYSTEM  ITEM NAME     LENGTH COUNT                  TYPE
                    --------------------------------------------------------
                0. CHILD   MATCH REGISTER           1                CHANGE
                       CMD LIST >>>>> DISPLAY MATCH

     TRANDEBUG> continue 

                DATA BREAKPOINT ENCOUNTERED, EXECUTION STOPPED
                ---> MATCH REGISTER CHANGED

                Match Register:
                item1      EQ   :  123        AND
                item2      EQ   :  ABC        OR
                item2      EQ   :  DEF

MPE/iX 5.0 Documentation