BEXT

Bit Extract

BEXT rd, rs1, rs2

Extracts the value of a single bit (0 or 1) at the index specified by rs2. The result is placed in the LSB of rd.

Encoding

Binary Layout

0100100

31:25

rs2

24:20

rs1

19:15

101

14:12

rd

11:7

0110011

6:0

 

Format R-Type

Opcode 0x48005033

Extension Zbs

Operands

• rd
  Dest (0 or 1)
• rs1
  Source
• rs2
  Index

Example

BEXT x10, x11, x12

// x10 = (x11 >> x12) & 1

Related

More in Zbs

Reference

View in RISC-V Unprivileged ISA Specification ↗ RISC-V ISA Manual

Description

BEXT extracts the single bit of rs1 selected by the lower log2(XLEN) bits of rs2, zero-extending to XLEN and writing to rd.

Operation

R[rd] = (R[rs1] >> (R[rs2] & (XLEN-1))) & 1;