Advanced Micro Devices Inc (AMD)

[dacaw]

Parallel execution


"The second example has to execute sequentially as they all
modify EAX."


Accessing memory is much slower than a register dependancy, by factors of 10. By increasing code size you are creating memory accesses. I think you'll find that the load unit can queue these accesses anyway.

Download CodeAnalyst and look at the (simulated) code execution.

If you want a real speedup think about the ja opcode - tests the CF and ZF in one instruction. One of my favorite tricks!