bt

Bit Test

BT r/m, r

Selects a bit and stores it in CF.

Details

The Bit Test instruction selects a bit and stores it in CF.

Pseudocode Operation

CF <- bit(SRC, offset)

Example

BT rbx, rax

Encoding

Binary Layout
0F
+0
A3
+1
 
Format Legacy
Opcode 0F A3
Extension Base

Operands

  • dest
    Register or memory operand
  • src
    General-purpose register