Sum of Digits.

[Didier Lachieze]

Nice programs, here is a shorter version that keeps the stack unchanged excepted for X replaced by it's sum of digits.

Code:

001 LBL'SD'
002 LocR 001
003 SDR 001
004 STO+ .00
005 IP
006 STO- .00
007 x[!=]0?
008 BACK 005
009 x<> .00
010 SDL 001
011 END

Notes: Local registers allocated by LocR are initialized to 0, so no need to clear them. Division and multiplication by a power of 10 can be replaced by the single step instructions SDR and SDL.