51 votes
Accepted

Did any processor implement an integer square root instruction?

Yes. The Harris RTX 2000 Forth CPU offered a multi-step square root instruction, as did its military-grade sibling, the RTX 2010. There may have been others, but that is the one I know of. See: ...
RichF's user avatar
  • 9,336
42 votes

Did any processor implement an integer square root instruction?

Is 1946 retro enough? From Wikipedia: ENIAC used four of the accumulators (controlled by a special multiplier unit) to perform up to 385 multiplication operations per second; five of the accumulators ...
John Doty's user avatar
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17 votes

Did any processor implement an integer square root instruction?

It's not that easy. The most efficient method to calculate square root is to calculate inverse/reciprocal of the square root using Newton-Raphson iterations, and then multiply it with the original. ...
user3528438's user avatar
  • 1,395
8 votes

Did any processor implement an integer square root instruction?

The claim in another answer of the Quake trick being the most efficient has not been true for a long time, and was only true regarding low-quality results for floats on specific hardware. On pretty ...
Chris Lomont's user avatar

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