Thats right.

bmap_purge is seldom used.
It is mostly for memory minimisation by 'freeing' video memory used by
'seldom' access bmaps.

BMAP_remove is for 'truely' removing a bmap. I it does a bmap_purge during the remove process.

PTR_remove is for removing any object. I BELIEVE it will do a bmap_purge as I understand it...
I THINK the ptr_remove checks what type the object is, and then performs the
appropriate '???_remove' process. (ie bmap_remove, str_remove, ent_remove, etc)