CODE DUP 1 chkPS, AX POPx, AX PUSHx, AX PUSHx, ;CODE
CODE ?DUP 1 chkPS, AX POPx, AX AX ORxx, AX PUSHx,
    IFNZ, AX PUSHx, THEN, ;CODE
CODE DROP 1 chkPS, AX POPx, ;CODE
CODE SWAP AX POPx, BX POPx, AX PUSHx, BX PUSHx, ;CODE
CODE OVER ( a b -- a b a ) 2 chkPS,
    DI SP MOVxx, AX [DI] 2 MOVx[]+, AX PUSHx, ;CODE
CODE PICK
    DI POPx, DI SHLx1, ( x2 )
    CX DI MOVxx, CX 2 ADDxi, CALLn, lblchkPS @ RPCn,
    DI SP ADDxx, DI [DI] MOVx[], DI PUSHx,
;CODE