INC and DEC Instructions

The instruction adds 1 to a single operand, and the instruction subtracts 1 from a single operand.

INC — Increment

Usage: INC dest

Flag O D I S Z A P C
Result *     * * * *  

Adds one to destination unsigned binary operand.

Clocks
Operand 286 386 486 Size Bytes
reg8 2 2 1 2
reg16/32 2 2 1 1
mem 7 6 3 2-4

DEC — Decrement

Usage: DEC dest

Flag O D I S Z A P C
Result *     * * * *  

Unsigned binary subtraction of one from the destination.

Clocks
Operand 286 386 486 Size Bytes
reg8 2 2 1 2
reg16/32 2 2 1 1
mem 7 6 3 2-4


INC X+1 ADD X+1, 1 DEC [OFFSET X] 
 INCLUDE Irvine32.inc
 .data
  X   WORD  1234h
 .code
 main PROC
  inc    X+1
  movzx  eax, X
  call   WriteHex
  exit
 main ENDP
 END main
 
 INCLUDE Irvine32.inc
 .data
  X   WORD  1234h
 .code
 main PROC
  add    X+1, 1
  movzx  eax, X
  call   WriteHex
  exit
 main ENDP
 END main
 
 INCLUDE Irvine32.inc
 .data
  X   WORD  1234h
 .code
 main PROC
  mov    ebx, OFFSET X
  dec    [ebx]
  movzx  eax, X
  call   WriteHex
  exit
 main ENDP
 END main
Output Output Output

 

 

 

 

 

 






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      ― Unknown