TRACE - the timesharing trace package.

TRACE is a debugging package normally used in conjunction with LODT or the "+Trace" option of the GO command. Under TRACE, the user is allowed to execute his subsystem or program in a controlled environment where all instructions can be checked for validity before execution.

The TRACE package can also be loaded with your program from the standard library by symref'ing the external name "TRACE". If this is done, initial control is passed to the package by executing

TSX1 TRACE
  or
XED TRACE

In Fortran-66, the statement "CALL TRACE" will accomplish this.

How do you tell if you are in TRACE? Well, whenever you enter TRACE, TRACE will print:

<address>?

where <address> will be the starting address of your program in octal (or symbolically if symbol tables are present), and wait for you to type in TRACE commands. The number in front is the location from where TRACE was called (normally this is the starting location of your program).

Using TRACE, the user has the ability to:

Print out each instruction before it executes.
Print out specified instruction before they execute.
Print out instruction that modify specified registers.
Print out instructions that modify specified locations in
     memory.
Print out various contents of his memory.
Print out the contents of his registers.
Change the contents of his memory or registers.
Insert and remove breakpoints.
Obtain an execution profile of the program.
Perform oct to decimal and decimal to octal conversions.
Search memory for specified data patterns.
Find the starting locations of his routines.

Notes:

At some sites, the enhanced TRACE may only be invoked via the GO command.

Index to TRACE commands

• ABORt - terminate execution via drl abort.
• ALLOcate - allocate some patch space.
• AT or ATA - set action breakpoint.
• B or BA - establish breakpoint.
• BC - call a B function and print the returned (octal) value
• C - enable control via break key.
• CALL - call a TSS command.
• COMMANDS - summary of trace commands.
• D or DA - delete breakpoint
• DEC - convert from decimal to octal
• DISPlay - display trace-related information
• Trace Display Index
• DONE - terminate execution via drl return
• E - execute instructions
• EF - Execute Force.
• ERROR - error messages and their meanings.
• EVAL - evaluate an expression.
• EXPRESSIONS - Symbolic expressions accepted by trace.
• F or FA - find data pattern in memory
• I - initialize or reset various things.
• Index for "expl trace"
• L - look up symbols or address.
• LP - search for PL/1 entry points.
• M - MA,MQ,ME,MI,MXn,MARn modify register
• N - disengage trace mechanism
• NOPAuse - discontinue pause mode
• NOTRace - disengage trace mechanism
• O - establish offset
• OCT - octal to decimal conversion
• P or PA - patch memory
• PASS - pass an input string into the DRL KIN buffer
• PAUS - pause before instruction execution
• Q - queue trace output.
• R or RA - run (i.e., resume execution)
• RESTORE - restore program state from last SAVE command.
• S - snap memory
• SAVE - save current program state
• SH, SHA, SHOW - show breakpoint locations
• SHOW - Show breakpoints.
• SOFF - symbol table off
• SON - cause the trace package to use the symbol table
• TRACE - syntax of trace commands.
• T - engage trace mechanism
• TC - trace continue.
• TERMinate - terminate execution via DRL RETURN
• TRACE - engage the trace mechanism.
• Trace Trace Index
• USE - user automatic commands for trace package.
• X,XA,XQ,XE,XEA,XEAQ,XI,XB,XN,XF,ARn - display registers.

See Also:

expl go

for the syntax required to specify the "+Trace" option.

expl trace index

for pointers to more information.

Copyright © 1996, Thinkage Ltd.