The PowerPC®, also known by the acronym PPC, is a processor architecture created in 1991 by a group of computer manufacturers. It is basically a Reduced Instruction Set Computing (RISC) processor that can alternate its data orientation. From 1994 to 2006, Apple® Incorporated's line of Macintosh® computers used the PPC as the central processor. It is also frequently used in video games and embedded controllers, including network devices and automotive applications.
The single-chip PowerPC® is based on the Power Architecture® developed in 1990 by International Business Machines Corporation (IBM®). This high-performance, multiple-chip RISC architecture evolved into the PPC with the help of Apple® Incorporated and Motorola Incorporated. The PPC was designed for performance superior to the Complex Instruction Set Computing (CISC) processors in personal computers. Despite being embraced by most operating systems, the PPC didn't gain much of that market. Outside of the Macintosh® line, very few software applications were developed for PPC-based personal computers.
Most PowerPC® chips include the ability to alternate between little-endian and big-endian orientation. This byte order switch can occur while the processor is running. Some PowerPC® chips allow each page of memory to utilize a different orientation. Others allow the operating system to use one orientation while the rest of the system utilizes the other. When switching orientation, large amounts of byte swapping may be needed to ensure the proper order is used with motherboard devices and external hardware.
Several enhancements to the original Power Architecture® are provided by the PowerPC®. These include a unique memory management architecture and many math-related instructions. There is also a 64-bit version of the PPC that is backward-compatible with the more common 32-bit chip. Some complex Power Architecture® instructions were also removed from the original PPC design for efficiency reasons.
After the initial PowerPC® was released, IBM® continued to develop the Power Architecture® line. Later processors were compatible with the original PPC instruction set and are often used in large servers. Several mass-market video game systems utilize PowerPC® processors as well.
Application-Specific Integrated Circuits (ASICs) sometimes include a PPC processor core in their design. This has led to a great variety of embedded systems based on the PowerPC®. Vehicle control systems frequently use them, including cars and at least one jet fighter. PPCs are also common in some types of networking equipment such as routers. Most real-time embedded operating system kernels and tools support the PPC, making system development straightforward.
