Jul 182003

In a word: no.

CMOVcc had potential when it was introduced in the Pentium Pro, but it is now completely useless. Based on empirical observation I’m guessing that the Pentium III and Pentium IV chips have shoved CMOVcc off the core processor into glacial pipeline-blocking microcode because the execution performance of CMOVcc on modern processors is *considerably* slower than discreet test and jump sequences.

The x86 instruction set has evolved into being a CISC architecture with a RISC core. Best performance is usually realized by using the fewest and most primitive kinds of instructions you can get away with, since those are the most likely to be implemented efficiently in the RISC core.

K.I.S.S. rules the day.

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