Portable Bitwise Manipulation Intrinsics

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The intrinsics are named after their CPU instruction and organized in modules named after their instruction set: bitintr::{instruction_set}::{intrinsic_name}.

They are implemented for all integer types except u128/i128. Whether a fallback software implementation is used depends on the integer types involved and the instruction sets supported by the target.

The following instruction sets are implemented:

• ABM: Advanced Bit Manipulation instructions.
• TBM: Trailing Bit Manipulation instructions.
• BMI: Bit Manipulation Instruction Set 1.0.
• BMI2: Bit Manipulation Instruction Set 2.0.

Example

extern crate bitintr;
use bitintr::bmi2::*;

fn main() {
    let x = 1;
    let y = 0;
    // Intrinsics can be used as methods:
    let method_call = x.pdep(y);
    // And as free function calls:
    let free_call = pdep(x, y);
    assert_eq!(method_call, free_call);
}

Supported compilers

The minimum requires rustc version is >= 1.4.0.

When compiled with a rust stable compiler the intrinsics are implemented using the software fallback. In release builds LLVM often generates the corresponding CPU instruction.

When compiled with a rust nightly compiler the following features are used to generate the corresponding CPU instruction in all cases:

• cfg_target_feature for target-dependent behavior,
• platform_intrinsics for using the bitwise manipulation intrinsics, and
• u128 support for efficient 64bit multiplication.