The PowerPC is an architecture of microprocessors developed jointly by Apple, IBM and Freescale (ex- Motorola Semiconducteurs). It uses a model RISC, privileging pipeline and reduced Instruction set. The architecture of PowerPC is directly derived from architecture POWER ( Performance Optimization with Enhanced RISC ) of IBM.
An high degree of parallelism makes it possible to carry out sometimes up to four or five operations simultaneously, for example multiplication and office plurality, test, and conditional connection.
Also known under the name of PPC , this architecture is used nowadays, in particular in onboard computing, because of its low fuel consumption and sound high parallelism which allows processing capability equal to work with frequencies of clock much lower (the technicians indicate by joke PowerPC like an athlete in the middle slow ). It equips for example certain products Cisco.
In microprocessing, it is especially used by the Macintosh of Apple (certain models of Macintosh: Power Mac, PowerBook, IMac, IBook, EMac, mini Mac). It is also used in the waiters of IBM and Apple. Several models of PowerPC followed one another in the computers of the firm apple, the PowerPC 601 made the first its entry, follow-up of the PowerPC 603, PowerPC 604, PowerPC G3, PowerPC G4 and of the PowerPC G5. AmigaOne and Pegasos, two machines new generation succeeding the Amiga of origin, are them also equipped with processors PowerPC G3 or PowerPC G4.
Since June 2005, Apple turned to the processors of mark Intel. According to Steve Jobs (chairman from Apple), IBM does not manage any more to produce sufficiently powerful and less greedy processors in energy compared to the competition of which Intel in particular. The PowerPC transition towards Intel began beginning 2006 to finish at the time of the WWDC of August 2006. Apple thus puts fine at a very long collaboration between Big Blue (IBM) and the Apple (Apple). However, that should not generate large changes for IBM since the section microprocessors intended for Apple represents less than 5% of the production of IBM. According to other semi-official sources, Steve Jobs refused to pay at IBM the expenses of technological research to create new PowerPC
PowerPC also are very much used in the game consoles. In 1995, a PowerPC 602 equipped a prototype with the game console Pippin of Apple, then replaced by one 603 given rhythm with 66MHz on the final version. Indeed PowerPC 602 is especially planned for the embarked Systèmes. A PowerPC Gekko, derived from the G4, is used in the console GameCube. But it is mainly in the nearest consoles generation that PowerPC will be much used (Xbox 360 and Nintendo Wii in particular). The Ps3 using a processor CONCEALMENT alliance of IBM and Sony, rather different from architecture PPC.
It is disadvised programming PowerPC in Assembleur if one wants to obtain a code which is at the same time powerful and easy to maintain. The experiment shows indeed that the programming in High-level language associated with the options of optimization of the Compilateur (equipped with a Algorithme of chromatic allowance of the registers) does always better than more tried out programmers.
The reason is that for using well the pipeline of PowerPC, it is necessary to gather in sequence the of the same instructions codes (load, or blind, or multiply and add) and that if that largely improves the speed of execution that hardly helps with legibility, and less still with the debugging !
Performance
PowerPC are very much used in the supercomputers. Thus, in June 2005, among the 9 most powerful computers of planet, 6 are containing PowerPC processors. (source: top500.org)
(Apple to Use Intel Microprocessors Beginning in 2006)
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