26-bit computing: Difference between revisions

Revision as of 19:05, 9 February 2006

Revision as of 22:09, 3 March 2007

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In [[ARM Limited|ARM]] [[ARM_architecture|processor architecture]], '''26-bit''' refers to the design used in the original ARM processors, where the [[Program Counter]]('''PC''') and [[Status_register|Processor Status Register]]('''PSR''') were combined into one 32-bit [[Processor_registers|register]] (R15), the Status flags filling the high 6 bits and the Program Counter taking up the lower "26" bits.

''(The Program Counter is always word-aligned, so the lowest two bits are always zero. The designers took advantage of this and used these two bits of the PC to hold the processor's mode bits.)''