Browse Prior Art Database

Virtual Region Mapping Disclosure Number: IPCOM000064893D
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19

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Related People

Childs, AD Mustain, RG Rader, HA [+details]


Providing extended addressability for programs limited to 64K bytes by a 16-bit architecture requires a method of altering the address space definition. Hardware registers called address translation registers (ATRs) control address-space definition. Programs need a generalized mechanism, independent of the physical ATRs, that allows extended addressability without compromising system integrity. Virtual region mapping (VRM) provides a generalized address management facility with: - A single instruction to alter any part or all of the address space. - Multiple distinct storage elements addressable within a single region. - Implicit mapping using transfer of control Supervisor Call (SVC). VRM provides a microcode instruction called the MAP instruction.