Patent ID: 8103851
Filing Date: 2012-01-24
Classification: G06F

Abstract:
1. A computer program product for translation of a virtual address into a translated address of a desired block of main storage in a computer system of a machine architecture, the computer program product comprising: a storage medium readable by said computer system, said computer readable medium storing instructions for performing: obtaining the virtual address to be translated; obtaining an initial origin address of a translation table of a hierarchy of translation tables, said hierarchy of translation tables comprising a segment table; based on the obtained initial origin address, obtaining a segment table entry from said segment table, said segment table entry configured to contain a format control field; in response to an enhanced Dynamic Address Translation (eDAT facility being enabled, wherein said segment table entry comprises a format control field, determining whether said format control field consists of an enabled value or a not-enabled value, wherein the not-enabled value of the format control field indicates the segment table entry consists of a first set of functional fields and an origin address of a page table, wherein the enabled value of the format control field indicates the segment table entry consists of the first set of functional fields, a second set of functional fields and a segment-frame absolute address of a large block of main storage; and in response to said format control field having the enabled value, performing: combining said segment-frame absolute address with a page index portion of said virtual address and a byte index portion of said virtual address to form the translated address of the desired block of main storage within said large block of main storage the formed translated address consisting of said segment-frame absolute address, said page index portion of said virtual address, and said byte index portion of said virtual address, said desired block of main storage consisting of one or more bytes of data; and accessing said desired block of main storage addressed by said translated virtual address.