TRACE Use the TRACE command to trace spec1r1ea macn1ne activity and to record the at the terminal, on a virtual spooled printer, or on
both and printer. If you issue more than one TRACE command, t}1e operands 3.re cumulative; that is, operands specified for the first
time activated, whereas those specified with new modifiers are
updated. The RUN and NORUN operands, however, can be specified in
different TRACE commands for different tracing functions and do not
cause 3. The format of the TRACE command is:
r------------ I 1 r ,
\ , TRace SVC 1
1 PRINter I I I/O I r , r , , , PROqram , ITERMi.ngll I NO!!!!!! I , , EXTernal , IBOTH I I RUN , I I PRIV I L .J L J I , SIO I I I ccw I OFf , , BRanch
L .J , INSTruct I I CSW I I END I I than one of these activities may be traced by using a single I TRACE :;ommand. For example: , , TRACE SVC SIO PRINTER
L SVC traces virtual machine SVC interrupts. I/O tra::es virtual machine I/O interrupts. PROGRAM traces virtual machine program interrupts. EXTERN ;\L virtual machine external interrupts. PRIV traces all virtual machine non-I/O privileged instructions. SIO tra::es TIO, eLFIO, HIO, HDV, and TCH instructions to all devices. Also traces SIO and SIOF instructions for
nonconsole and nonspool devices only.
ccw traces virtual and real CCWs for nonspool nonconsole device 110 operations. When CCW tracing is requested, SIO and TIO instructions to all devices are also traced. tra::es virtual machine interrupts, PSi instructions, and
successful branches. INSTRUCT tr3.ces all instructions, virtual machine interrupts, and
successful branches.
section 5. Format of CP Commands 161
ALL traces all instructions, interrupts, successful branches,
privileqe instructions, and virtual machine I/O operations. CSW provides contents of virtual and real channel status words at I/O interrupt.
END terminates all tracinq activity and prints a termination messacre. PRINTER directs tracinq output to PRINTER is specified, RUN is NORUN can be specified.
a virtual spooled printer. If
assumed; however neither RUN nor directs tracing output to the terminal (virtual machine
console). BOTH directs tracing output to both a virtual spooled printer and
the terminal. OFF halts tracing of the specified activities on both the printer
and terminal. RUN stops proqram execution after the trace output to the terminal
and enters the CP command environment. If a Diagnose code X'OOS' is being traced, NORUN has no
effect and program execution does not stop.
continues the program execution after
terminal has completed and does not
environment.
the trace output to the
enter the:P command
1. If vour virtual machine has the virtual=real option and NOTRANS set
on, CP forces CCW translation while tracing either SIO or :CW. When tracing is terminated with the TRACE END command, CCW translation is bypassed again.
2. If hardware assist is enabled on your virtual machine, CP
turns it off while tracing SVC, PRIV, BRANCH, INSTRU:T, or ALL If virtual interval timer support is available on your
processor and is active (that is, SET ASSIST TMR is in effect), CP
turns the timer support off while tracing external interrupts.
After the tracing is terminated with the TRACE END command, CP
turns hardware assist on again.
3. If trace output is beinq recorded at the terminal, the virtual machine stops execution and CP command mode is entered after each
output messaqe. This simulates the instruction step function.
However, all processing associated with "the event being traced is
completej and, therefore, execution may have stopped after an
instruction has executed and the PSW has been updated.
For example, a privileged instruction traced with the PRIV operand stops after the privileged instruction executes, whereas the same
instruction traced with the ALL operand stops before the
instruction executes.
To determine whether the traced instruction has executed, display
the virtual machine PSW. 162 IBM VM/370 CO Command Reference for General Users
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