msichert

3 ms·

1.
by msichert 5mo ago
Vector instructions usually don't have overflow flags, so a compiler can't easily vectorize loops containing overflow checks. However, detecting overflows in integer operations requires only a bit of bitwise arithmetic. In my expe
2.
by msichert 6mo ago
That's very interesting, I'm only familiar with the C++ standard where bit shifts are defined in terms of multiplications and divisions by powers of 2: https://eel.is/c++draft/expr.shift So it seems in regard
3.
by msichert 9mo ago
That's a good point. We just use pointer tagging in many different places (e.g. for pointer swizzling in our buffer pages), so including a few bits of information in a pointer just seemed obvious.
4.
by msichert 9mo ago
If you want to improve equality matching for longer strings, you could even store a 4B hash of the entire string instead of the prefix. I guess that should work well if you equality match on URLs since their prefix is always "http&quot
5.
by msichert 9mo ago
We chose 4B because that was the maximum number of bytes that would be unused otherwise (4B for the length, 8B for the pointer leaves 4B), the UTF8 encoding doesn't really matter. Also, for UTF8 specifically, cutting code points in hal
6.
by msichert 2y ago
I would tend to refuse such an offer but not because of an irrational fear of crypto. Rather, I would have very real concerns about the value of the tokens: How do I know they will be worth anything when the company exits? I probably won&#x
7.
by msichert 2y ago
Hey, I'm the author of the blog post! I had planned to write about the Kahan summation, but I didn't want to overload the blog post with too many different concepts. I'm definitely considering writing about it in a follow-up