PPC
       PowerPC (Apple)

	

	PPC
       Program to Program Communication (Apple)

	

	PowerPC
PPC

    (PPC) A RISC microprocessor designed
   to meet a standard which was jointly designed by Motorola,
   IBM, and Apple Computer (the PowerPC Alliance).  The
   PowerPC standard specifies a common instruction set
   architecture (ISA), allowing anyone to design and fabricate
   PowerPC processors, which will run the same code.  The PowerPC
   architecture is based on the IBM POWER architecture, used in
   IBM's RS/6000 workstations.  Currently IBM and
   Motorola are working on PowerPC chips.

   The PowerPC standard specifies both 32-bit and 64-bit data
   paths.  Early implementations were 32-bit (e.g. PowerPC
   601); later higher-performance implementations were 64-bit
   (e.g. PowerPC 620).  A PowerPC has 32 integer registers (32-
   or 64 bit) and 32 floating-point (IEEE standard 64 bit)
   floating-point registers.

   The POWER CPU chip and PowerPC have a (large) common core, but
   both have instructions that the other doesn't.  The PowerPC
   offers the following features that POWER does not:

   Support for running in little-endian mode.

   Addition of single precision floating-point operations.

   Control of branch prediction direction.

   A hardware coherency model (not in Book I).

   Some other floating-point instructions (some optional).

   The real time clock (upper and lower) was replaced with the
   time base registers (upper and lower), which don't count in
   sec/ns (the decrementer also changed).

   64-bit instruction operands, registers, etc. (in 64 bit
   processors).

   See also PowerOpen, PowerPC Platform (PReP).

   IBM PPC info
   (http://fnctsrv0.chips.ibm.com/products/ppc/index.html).

   (gopher://info.hed.apple.com/), "Apple Corporate News/"
   (press releases), "Apple Technologies/" and "Product
   Information/".  (gopher://ike.engr.washington.edu/), "IBM
   General News/", "IBM Product Announcements/", "IBM Detailed
   Product Announcements/", "IBM Hardware Catalog/".

   Usenet newsgroups: news:comp.sys.powerpc,
   news:comp.sys.mac.hardware.

   ["Microprocessor Report", 16 October 1991].

   (1994-09-30)