Viewing profile — 2102922286

Here's a video made 53 years ago about how we need to tackle pollution: https://www.youtube.com/watch?v=MA45iKHjoGg A lot of it still rings true today. The sad thing is that we _kn…

https://uops.info/uiCA.html it's really cool!!

This is one area where Profile-Guided Optimization (PGO) can help a lot! With PGO, you run your program on some sample input and it logs info like how many times each side of a bra…

For the given assembly from the blog post loop: lea (%rdx,%rax,4),%rcx cmp (%rcx),%esi cmovg %rcx,%rdx shr %rax jne loop Here's a simulated CPU trace on Intel skylake: https://uica…

If what you're saying is (roughly) cmovne rax, rdx jmp rax that is, a cmov followed by an indirect jump to the address contained in rax, "jmp rax" is _always_ an indirect jump. It …

When implementing cryptographic primitives, you want to avoid branching on secret values. The reason why is that the CPU's branch predictor will attempt to predict the value that y…

Cmov doesn't branch. A branch refers specifically to the program counter ending up in more than one possible place after an instruction has executed. It is this behavior that mucks…

A cool related algorithm is https://algorithmica.org/en/eytzinger In addition to being branchless, it also has better cache properties than a standard binary search tree. If you're…

cmov (i.e. conditional move) doesn't branch. By branch here, we mean "at point at which the successor program counter value might be one of two locations." It's true that this _doe…