; DCPU-16 example: memory copy loop and subroutine call
; From the original DCPU-16 specification by Notch (Markus Persson)

              SET I, 10               ; set loop counter to 10
              SET A, 0x2000           ; set A to base address
:loop         SET [0x2000+I], [A]     ; copy memory word at [A] to [0x2000+I]
              SUB I, 1                ; decrement counter
              IFN I, 0                ; if I != 0
                SET PC, loop          ; jump back to loop

; Call a subroutine
              SET X, 0x4              ; set X to 4
              JSR testsub             ; call subroutine testsub
              SET PC, crash           ; jump to crash if subroutine returns normally

; Subroutine: shifts X left by 4
:testsub      SHL X, 4               ; X = X << 4 (should become 0x40)
              SET PC, POP             ; return from subroutine

; Hang forever (X should be 0x40 if everything went right)
:crash        SET PC, crash           ; infinite loop