IA Instructions Vary in Length and Are Complex
The IA32 instruction set is cumbersome to deal with. A single instruction can be anywhere from one to 15 bytes in length. Attempting to decode and dispatch such instructions at a very high clock rate is counter productive. The Pentium® Pro was the first IA32 processor to translate legacy x86 IA Instructions into primitive, fixed-length μops prior to dispatch and execution.
IA instructions are prefetched from memory and are placed into the unified L2 Cache. As blocks (i.e., lines) of IA instructions are obtained from the L2 Cache, the processor parses them to identify the boundaries between instructions. It then decodes each of the variable-length IA instructions into fixed-length μops. Decoding and ...
Get The Unabridged Pentium 4 IA32 Processor Genealogy now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
