Retro1.org codex

SYSTEM                                                   CP Privilege Class:  G

Use the SYSTEM command to simulate the action of the RESET and RESTART buttons
on the real computer console, and to clear storage.  The format of the SYSTEM
command is:
+----------+------------------------------------------------------------------+
| SYStem   | CLEAR|RESET|RESTART                                              |
+----------+------------------------------------------------------------------+
where:

CLEAR    clears virtual storage and virtual storage keys to binary zeros.

RESET    clears all pending interrupts and conditions in the virtual machine.

RESTART  simulates the hardware system RESTART function by storing the current
         PSW at virtual location eight and loading, as the new PSW, the
         doubleword from virtual location zero.  Interrupt conditions and
         storage remain unaffected.


Usage notes:

1.  The CLEAR, RESET, and RESTART functions leave the virtual machine in a
    disabled wait state.  Both CLEAR and RESET clear pending interrupts, and
    load a PSW of all zeros with only the WAIT bit set on
    (X'0002000000000000').

2.  After issuing the SYSTEM command with RESET or CLEAR specified, either
    STORE a PSW and issue BEGIN or issue BEGIN with a hexadecimal storage
    location specified, to resume operation.  The virtual machine automatically
    restarts at the location specified in the new PSW (which is loaded from the
    doubleword at location zero) after the SYSTEM RESTART command is processed.

Responses:

STORAGE CLEARED - SYSTEM RESET
   is the response given if the command SYSTEM CLEAR is entered.

SYSTEM RESET
   is the response given if the command SYSTEM RESET is entered.

If the command SYSTEM RESTART is entered, no response is given; the virtual
machine resumes execution at the address in the virtual PSW loaded from virtual
storage location X'0'.