tzcnt

Count Trailing Zeros

TZCNT r32, r/m32

Counts the number of trailing zeros.

Details

The Count Trailing Zeros instruction counts the number of trailing zeros.

Pseudocode Operation

DEST <- count of trailing zero bits in SRC

Example

TZCNT eax, ebx

Encoding

Binary Layout
F3
+0
0F
+1
BC
+2
 
Format Legacy
Opcode F3 0F BC
Extension BMI1

Operands

  • dest
    32-bit general-purpose register (e.g. EAX)
  • src
    32-bit register or memory