[JdeBP]

In terms of actual hardware, a general-purpose multiply+adder is actually just a multiplier with one extra row for the addend. NxN multipliers are implemented as an N-row addition (of one multiplicand shifted and masked by the bits of the other). One more row is very cheap compared to running two operations through an ALU that only has separate multiply and add hardware.

In general, outwith ALUs as well as in, it is very cheap to fold any (reasonable) number of additions and subtractions, even ones with constant left/right shifts/rotates to the addends and subtrahends, into multipliers.

[Y_Y]

Are you using the word "outwith" to be funny, or is this really idiomatic in some dialect? I've seen people using "within and without" to mean "inside of and outside of" but not in anything written in the last hundred years.

[bloak]

The word "outwith" is used in Scotland. I'm not Scottish, but I've heard Scots use the word, and Oxford English Dictionary has recent quotations for it from Scottish newspapers.

[Y_Y]

Very interesting, thank you.

> Scottish Twitter users 'shocked' after discovering the word 'outwith' is only used in Scotland [0]

[0] https://www.dailyrecord.co.uk/scotland-now/scottish-twitter-...

[JdeBP]

And Hacker News within just the past 5 days. (-:

* https://news.ycombinator.com/item?id=26438656

* https://news.ycombinator.com/item?id=26399177