PURPOSE: To curtail a simulation overhead of a virtual machine control program VMCP by executing directly a privileged instruction for controlling a control register, and deciding an interruption to the VMCP by a hardware.
CONSTITUTION: When a privileged instruction issued from a virtual machine VM3 and decided to be a direct executing mode by an actual computer 1, occupies a control register of the actual computer 1 by an actual computer use microprogram 12, and in other case, it is processed by a firmware assist VMA microprogram 13. In case it is processed by the actual computer use microprogram 12, whether it is necessary to execute an interruption to a VMCP or not is decided by a decision use hardware 14, but the decision processing as to whether a submask is changed or not, and whether the submask is "1" or not is executed by a hardware at a high speed. In case the condition is formed, the interruption is executed to the VMCP, and if it is not formed, the control is returned to the VM3.
UMENO HIDENORI
KUBO TAKASHIGE
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