Indirect Space Id in an Extended Address Mode
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
A technique is described whereby a computer's extended address feature provides a control to access a user's space which is mapped by a different segment table. To provide this function, an indirect Space Identifier (SID) is implemented as an extension to the format of a set segment table entry. The figure shows how the set segment table entry functions. When the register 9 is specified by an R1 instruction, the address specifies the target SID and the segment address. The target SID is controlled by address space array 10 so that the target SID may be added by adder 11 with the segment address 12. When the information is combined with the address from segment table cache 13, the indirect SID is entered into target segment table 14, so as to provide the mapping from different segment tables.