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.

Details

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

Pseudocode Operation

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

Example

BEXT x10, x11, x12

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 0x33
Extension Zbs

Operands

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