How to build ATC Carousel in linuxcnc ?

[RS274NGC]
...
REMAP= M6  modalgroup=6  prolog=change_prolog ngc=toolchange epilog=change_epilog

o<toolchange> sub

M19 R0  ;align the spindle

; only unload the tool if there is a tool in the spindle
; This assumes that the carousel is already aligned correctly. 
; It is important to unload the tool before shutting down the machine. 

O100 IF [#<tool_in_spindle> GT 0]
    G53 G0 Z -100
    
    M64 P2 ; move arm in
    M66 P2 L3 Q5 ; wait for arm-in = true
    O104 if [#5399 LT 0]
        (abort, failed to move arm in)
    O104 endif

    M64 P3 ; release tool
    M66 P3 L3 Q2 ; wait for tool-released = true
    O105 if [#5399 LT 0]
        (abort, failed to release tool)
    O105 endif

O100 ENDIF

    G53 G0 Z0

O200 IF [#<selected_tool> GT 0]

    M65 P1 ; unlock carousel
    M66 P1 L4 Q1 ; wait for locked=false
    O106 if [#5399 LT 0]
        (abort, failed to unlock carousel)
    O106 endif

    M68 E0 Q#<selected_pocket> ;set the carousel to move to the right pocket

    M64 P0 ; start carousel
    G4 P2
    M66 P0 L3 Q60 ; wait for carousel finished
    O107 if [#5399 LT 0]
        (abort, failed to align carousel)
    O107 endif
    M65 P0; stop carousel
    M64 P1 ; lock carousel
    M66 P1 L3 Q1 ; wait for locked=true
    O108 if [#5399 LT 0]
        (abort, failed to lock carousel)
    O108 endif

    M64 P2 ; move arm in (might already be in)
    M66 P2 L3 Q5 ; wait for arm-in = true
    O109 if [#5399 LT 0]
        (abort, failed to move arm in)
    O109 endif

    G53 G0 Z-100 ; pick up the tool

O200 ENDIF 

M65 P3 ; clamp tool
M66 P3 L4 Q2 ; wait for tool-released = false
O110 if [#5399 LT 0]
    (abort, failed to clamp tool)
O110 endif

M65 P2 ; move arm back out
M66 P4 L3 Q5 ; wait for arm-out = true
O111 if [#5399 LT 0]
    (abort, failed to move arm in)
O111 endif


o<toolchange> endsub [1]


M2