   0 ;;  test extended instruction
   0 .s
   0 inc 14
   0 ldd 15
   0 addx 16
   0 addx2 17
   0 .a 10
  10 .c
  10 	xd inc r1 r2 1	;; new instruction D-format
  11 	xl ldd r7 data  ;; L-format
  12 	xx addx r3 r4 r5 addx2  ;; X-format
  13 	.w 48230	;; raw 32-bit
  14 	.c		;; back to code
  14 	add r1 r3 #4	
  15 	add r1 r2 r3
  16 :data			;; data segment
  16 .w 11 22 33		;; size word
  19 .e
