dec

Decrement

DEC r/m

Decrements the operand by 1.

Details

The Decrement instruction decrements the operand by 1.

Pseudocode Operation

DEST <- DEST - 1
// Flags: OF, SF, ZF, AF, PF (CF unchanged)

Example

DEC rbx

Encoding

Binary Layout
FF
+0
ModRM
+1
 
Format Legacy
Opcode FF /1
Extension Base

Operands

  • dest
    Register or memory operand