Re:Building Your Own Efficient uint128 in C++
by wavemode on Sunday February 01, 2026 @10:56PM
(#46852232)
Maybe it's a typo for 512. I'm not even sure how you would achieve 564 in this context.
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Re:Building Your Own Efficient uint128 in C++
by PhilipTrettner on Friday February 06, 2026 @08:39AM
(#46912695)
It's actually not a typo. Our "real" internal code starts with integer bounds on the inputs (say 2^26) and then computes for each subexpression how many bits are actually needed to exactly represent that. That can even lead to fractional bits (like in "a + b + c"). The generated code then rounds up to the next 64 bit multiple.