Thanks! Yes I am also impressed by how relatively easy this is to implement at the machine level. One thing I meant to do for that article but didn't get to i

Thanks! Yes I am also impressed by how relatively easy this is to implement at the machine level. One thing I meant to do for that article but didn't get to is implement each of those algorithms in assembly directly and see if the C/C++ solution would compile into the optimal machine code (or something equally efficient). In assembly you have the luxury of no undefined or implementation-defined behavior. This makes things a lot easier, since you can count on things like two's complement. In assembly these checks are probably as easy as (untested): will_u64_overflow_u32: ; If any of the high 32 bits are set. shr rdi, 32 setne al ret will_u64_overflow_i32: ; If any of the high 33 bits are set. shr rdi, 33 setne al ret will_i64_overflow_i32 ; If the high 32 bits are other than all 0 or all 1. shr rdi, 32 add edi, 1 cmp edi, 1 seta al ret I'm not sure if these are exactly right, but I think the right answers are about this simple. Any of these could also be written simply in C/C++ also, the main difference is just that in assembly you can make machine-specific assumptions (like two's complement) since you're already doing something machine-specific.