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## xperm4

# Function xperm4

Source

    pub fn xperm4(rs1: usize, rs2: usize) -> usize

🔬This is a nightly-only experimental API. (`riscv_ext_intrinsics` #114544)
Available on target feature `zbkx` and (RISC-V RV32) and (RISC-V RV32 or RISC-V RV64) only.
Expand description

Nibble-wise lookup of indicies into a vector.

The xperm4 instruction operates on nibbles. The rs1 register contains a vector of XLEN/4 4-bit elements. The rs2 register contains a vector of XLEN/4 4-bit indexes. The result is each element in rs2 replaced by the indexed element in rs1, or zero if the index into rs2 is out of bounds.

Source: RISC-V Cryptography Extensions Volume I: Scalar & Entropy Source Instructions

Version: v1.0.1

Section: 3.48