| 摘要 |
A multi-address space control for use in a information processing system includes accessing a plurality of address spaces produced by different address translation table based on a selection command for a plurality of first address registers, and comparing a program status word key with a main storage key in a main storage to protect the main storage. The multi-address space control between different address spaces includes a PSW key register for holding the program status word key, a work access key register capable of arbitrarily designating an access key in accordance with a data transfer instruction, access apparatus for allowing an access to the main storage irrespective of the value of a main storage key when the value of the key selected by a selector as an access key from the work access key register and the PSW key register is a predetermined value, and setting apparatus for accessing the different address spaces by changing-over the plurality of leading address registers and the work access key register and PSW register, detecting an access exception, and setting the predetermined value in the work access key register to judge the work access key as an access key if an access exception is not detected.
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