Htmovflag

htmovflag has a nonzero value if the sprite is using a move command and it bumps into something (htmovflag is set to the return value of the movesprite function).

Depending if the moving sprite is bumping into another sprite, wall, floor or ceiling, a different value will be substracted to the ID of it. For example, the ID of another sprite will be equal to htmovflag - 16384.