I would assume that bmap_blit creates a bit more overhead instead of copying the raw pixel data, as it needs to do some more checks about the boundaries and such stuff.
Also, 8888 is not a valid bitmap depth wink

MrGuests looks for me also a bit risky, the new bmap couldn't be purged via ptr_remove() and if the source bitmap gets removed, you are probably pretty much fucked. Also: The internal structure might be changed in the future, destroying the memcpy approach completely.

Shitlord by trade and passion. Graphics programmer at Laminar Research.
I write blog posts at feresignum.com