Browse Prior Art Database

Method to Map PowerPC Boot ROM Space to x86 Boot ROM Space

IP.com Disclosure Number: IPCOM000118608D
Original Publication Date: 1997-Apr-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Lam, SH: AUTHOR

Abstract

Disclosed is a method for mapping the PowerPC* ROM space into the x86 ROM space. A PowerPC system can use the x86 PCI-ISA bridge chip when the mapping logic is implemented in the system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 59% of the total text.

Method to Map PowerPC Boot ROM Space to x86 Boot ROM Space

      Disclosed is a method for mapping the PowerPC* ROM space into
the x86 ROM space.  A PowerPC system can use the x86 PCI-ISA bridge
chip when the mapping logic is implemented in the system.

      At present, the PowerPC has not been adopted successfully as
expected.  Besides Apple** and a few Mac** clone companies who
developed the PowerPC system, no other significant IBM PC clones are
planning to  build PowerPC systems.  At times, the IBM PC clone
system was called an  x86 system.  To convince x86 system vendors to
build Mac clone systems,  the Processor Independent (PI) platform is
proposed.  This platform will  support Intel*** processors, as well
as PowerPC processors, and, thus,  reduce the risk for the PC clone
vendors in the event of desired withdrawal from the Mac clone market
later on.  The goals of the PI platform is to limit the changes to
the PC clone chipset as little as possible.  There are many
innovation ideas involved with the PI platform  and this invention is
one of them.

      Typically, in the x86 system the PCI-ISA bridge controls the
boot ROM.  In the PowerPC system, the boot ROM control logic was
either resided in the Host bridge or in the PCI-ISA bridge.  To
preserve the x86 system logic, use its PCI-ISA Bridge (PIB) for the
PI platform. The  problem is PC clone and PowerPC system have
different ROM memory map.  The PC clone ROM address is located at
FFF800...