anchor.diff:    :encoding (modrm imm)
     :rex.w t)
   
  -;;; Add imm32 to mem64
  +;;; To a 32-bit memory location (destination), add an immediate 32-bit
  +;;; sign-extended value (source), and store the result in the
  +;;; destination.
   (define-instruction "ADD"
     :modes (64)
     :operands ((memory 64) (simm 32))
  
positive.code: 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Add imm to reg/mem, 16/32/64
  ;;; Opcodes: 81
  ;;; Opcode extension 0
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Add imm16 to reg/mem16
  
  ;;; Add imm16 to reg16
  (define-instruction "ADD"
    :modes (32 64)
    :operands ((gpr 16) (imm 16))
  
negative.code: 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; To a 32-bit GPR or memory location (destination), add an immediate
  ;;; 32-bit value (source), and store the result in the destination.
  ;;; Add imm32 to reg/mem32
  
  ;;; To a 32-bit GPR (destination), add an immediate 32-bit value
  ;;; (source), and store the result in the destination.
  (define-instruction "ADD"
    :modes (32 64)
    :operands ((gpr 32) (imm 32))
  