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A comment on JITs are un-ergonomic. Parent comment

Re:JITs are un-ergonomic by im3w1l on Sunday March 29, 2020 @09:27AM (#22718817)
A fast memcpy used to be complicated to implement but these days I heard a simple

    rep movsb
will do the trick. This assumes that the source register points to source, destination register points to destination and counter register is set to number of bytes to copy.
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Re:JITs are un-ergonomic by pizlonator on Sunday March 29, 2020 @03:25PM (#22721835)
I wish that was true but my data says it isn't:

- A verbose SIMD copy loop is often faster even on modern Intel CPUs that have the more modern rep implementation.

- A simple byte copy loop will beat both SIMD and rep when you're copying smaller amounts at a time.

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