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Monday, April 22, 2013

x86/x64 CMOV Instruction vs ARM Conditional Instruction Execution

If you've been programming in x86/x64 assembler for a while now, you'll know the CMOV (Conditional Move) instruction. This instruction was introduced in P6 (Pentium Pro) for compiler optimization.

It seems that the conditional instruction execution in ARM (32-bit only?) predates the P6 CMOV instruction debut. Conditional instruction execution of course speeds up comparison statements in many occasions in our code. 

Now, did Intel "copied" the technique from the RISC world and applied it to x86 back then? 
IIRC, P6 (Pentium Pro) was the first Out-Of-Order CPU core from Intel. I recall that this architecture was more RISC-like on the inside.

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1 comment:

Anonymous said...

*snort*. The SPARC had them.