def syscall( int_code , codes)
      codes.append ArmMachine.mov( :r7 ,  int_code )
      codes.append ArmMachine.swi( 0 )
      codes
    end
def syscall( int_code , codes)
      codes.append ArmMachine.mov( :r7 ,  int_code )
      codes.append ArmMachine.swi( 0 )
      codes
    end
syscall is always triggered by swi(0)
 The actual code (ie the index of the kernel function) is in r7