BMI

Bit Manipulation Instructions (BMI) is an interesting extension for the x86-64 architecture, introduced by Intel in Haswell processors (early 2010s). Its main purpose is, as the name suggests, increasing the speed of the most common bit operations by replacing manual calculation with dedicated instructions (which means hardware support). This article will focus on the performance of three example instructions: BLSI (reads the lowest bit), BLSR (resets the lowest bit) and TZCNT (counts the number of trailing non-set bits).