! DDROP + DDUP +! DNEGATE - DROP 0 DSWAP 0< DUP 0= I 0BRANCH I' 1+ J 1- LEAVE 2* LIT 2/ NEGATE < NOP PICK NOT ROLL OR = OVER >R R> ?DUP R@ @ ROT ABS S->D AND SWAP BRANCH U* D! U/MOD D+ XOR D@