公开(公告)号：CA1293821C

公开(公告)日：1991-12-31

申请号：CA558930

申请日：1988-02-15

Applicant: IBM

Inventor： BEALKOWSKI RICHARD ,  DAYAN RICHARD A ,  DORIA DAVID J ,  KINNEAR SCOTT G ,  KRANTZ JEFFREY I ,  LIVERMAN ROBERT B ,  SOTOMAYOR GUY G ,  WILLIAMS DONALD D ,  VAISKAUCKAS GARY A

IPC: G06F9/06 ,  G06F12/02 ,  G06F12/08 ,  G06F12/10 ,  G06F12/14

Abstract: IBM Docket No. BC9-87-003 COMPUTER SYSTEM HAVING MODE INDEPENDENT ADDRESSING A computer system and method for operating a computer system capable of running in mutually incompatible real and protected addressing modes, in which programs written for one mode can be run in the other mode without modification. The BIOS assembles two different common data areas for the two modes, each inclusive of device block pointers, function transfer table pointers, data pointers, and function pointers. The common data area for the real mode is assembled first. To assemble the pointers for the protected mode common data area, the offset values from the real mode area are copied directly, and then selector values are inserted whose physical addresses correspond to the segments of the corresponding pointers in the real mode area. The selector values are derived from a segment descriptor table.