In a uniprocessor system there exists only one CPU, and the
    concept of SDA CPU context is not an issue. However for a
    multiprocessor system with more than one active CPU, SDA
    must maintain the concept of CPU context to provide a way of
    displaying information bound to a specific CPU, such as the
    reason for the BUGCHECK exception, the currently executing
    process, the current IPL, the contents of CPU registers, and
    any owned spinlocks. When SDA is first invoked to analyze a crash
    dump, the "SDA current CPU" is the CPU that induced the system
    failure.

    The CPU context can be changed by several different SDA commands.
    When the CPU context is changed, the "SDA current process" is
    changed to the current process on the "SDA current CPU" in order
    to keep CPU context and process context synchronized. If there
    is no current process on the "SDA current CPU", the "SDA current
    process" is undefined, and no process context information will be
    available until SDA process context is set to a specific process.

    Type HELP PROCESS_CONTEXT for specific information about the "SDA
    current process".

    The following SDA commands change the "SDA current CPU":

    SET CPU cpu_id   ! Changes the "SDA current CPU" to CPU cpu_id

    SHOW CPU cpu_id  ! Changes the "SDA current CPU" to CPU cpu_id

    SHOW CRASH       ! Changes the "SDA current CPU" to the CPU
                     ! that induced the system failure

    The following commands define the "SDA current CPU" to be the CPU
    on which the process is current, or the CPU on which the process
    was last executed:

       SET PROCESS process-name
       SET PROCESS/ADDRESS=pcb-address
       SET PROCESS/INDEX=nn
       SET PROCESS/NEXT
       SHOW PROCESS process-name
       SHOW PROCESS/ADDRESS=pcb-address
       SHOW PROCESS/INDEX=nn
       SHOW PROCESS/NEXT
       VALIDATE PROCESS process-name
       VALIDATE PROCESS/ADDRESS=pcb-address
       VALIDATE PROCESS/INDEX=nn
       VALIDATE PROCESS/NEXT

    No other SDA commands affect the "SDA current CPU".

                                   NOTE

       When analyzing the running system, the SET CPU and SHOW CPU
       commands are not allowed, since SDA does not have access to
       all the CPU-specific information on the running system.