Available on x86 or x86-64 only.
Expand description
Advanced Bit Manipulation (ABM) instructions
The POPCNT and LZCNT have their own CPUID bits to indicate support.
The references are:
- Intel 64 and IA-32 Architectures Software Developer’s Manual Volume 2: Instruction Set Reference, A-Z.
- AMD64 Architecture Programmer’s Manual, Volume 3: General-Purpose and System Instructions.
Wikipedia provides a quick overview of the instructions available.
Functions§
- _lzcnt_
u32 ⚠lzcnt - Counts the leading most significant zero bits.
- _popcnt32⚠
popcnt - Counts the bits that are set.