Thread:IAmAPersson/@comment-5106053-20131201015654/@comment-1595298-20131201025756

I think this is a slightly more accurate rendition (does the condition check before first execution of the loop body and handles negative values of S properly):

I=J

@LOOP

IF I*SGN(S)>T*SGN(S) GOTO @BREAK

'loop

I=I+S:GOTO @LOOP

@BREAK