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A leap year check in three instructions

(hueffner.de)
420 points gnabgib | 1 comments | 15 May 25 21:57 UTC | HN request time: 0.231s | source
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drewg123 ◴[15 May 25 22:47 UTC] No.44000124[source]▶
I tend to be of the opinion that for modern general purpose CPUs in this era, such micro-optimizations are totally unnecessary because modern CPUs are so fast that instructions are almost free.

But do you know what's not free? Memory accesses[1]. So when I'm optimizing things, I focus on making things more cache friendly.

[1] http://gec.di.uminho.pt/discip/minf/ac0102/1000gap_proc-mem_...

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1. timewizard ◴[16 May 25 04:59 UTC] No.44001975[source]▶
They're not free at all. They're unlikely to create noticeable latency; however, CPU clock speeds and thus power consumption haven't been constant for years now. You are paying for that lack of optimization and mobile users would thank you to do it.

There is no silver bullet.