CAW                                                            DEBUG subcommand

Use the CAW subcommand to display at the terminal the contents of the CAW
(channel address word) as it existed at the time the debug environment was
entered.

The format of the CAW subcommand is:
+----------+------------------------------------------------------------------+
| CAW      |                                                                  |
+----------+------------------------------------------------------------------+


Usage Notes:

1.  Issue the CAW subcommand to check that the command address field contains a
    valid CCW address, or to find the address of the current CCW so you can
    examine it.

2.  The three low-order bits of the command address field must be zeros in
    order for the CCW to be on a doubleword boundary.  If the CCW is not on a
    doubleword boundary or if the command address specifies a location
    protected from fetching or outside the storage of a particular user, the
    Start I/O instruction causes the status portion of the CSW (channel status
    word) to be stored with the program check or protection check bit on.  In
    this event, the I/O operation is not initiated.

Responses:  The CAW, located at storage location X'48', is displayed.  Its
format is:

Bits     Contents

0-3      The protection key for all commands associated with Start I/O.  The
         protection key in the CAW is compared to a key in  storage whenever a
         reference is made to storage.

4-7      This field is not used and must contain binary zeros.

8-31     The command address field contains the storage address (in hexadecimal
         representation) of the first CCW (channel command word) associated
         with the next or most recent Start I/O.