Assembly Optimization Tips by Mark Larson

Re:Assembly Optimization Tips by Mark Larson by Findecanor on Friday November 15, 2024 @06:19AM (#42145886)

Of course not. It is multiplication with a reciprocal in fixed-point representation. You'd first have to compute the reciprocal as 2**32 / divisor. Therefore it is most often done with constant divisors.

A longer tutorial that goes into more depth: https://homepage.cs.uiowa.edu/~jones/bcd/divide.html

[ Parent | on HN ]

Re:Assembly Optimization Tips by Mark Larson by 0xf00ff00f on Friday November 15, 2024 @06:38AM (#42146009)

Also, x86 has an instruction that multiplies two 32-bit registers and stores the 64-bit result in two 32-bit registers. So you get the result of the division in the register with the high part of the multiplication result, and don't need to do a shift.

[ Parent | on HN ]