FFIV?

Just a simlpe question: is FFIV advance a port of snes FFII or a port of FFC?

It's more of a remake. It's the same game as it's SNES and Playstation versions, but the GBA version has better graphics, has an ATB bar in battle, the difficulty has been toned down a bit, and two new dungeons have been added

It is not the same as the SNES version. It is much more similar to the Chronicles version, but it's closest to a port from the WSC with some significant enhancements.
Overworld, monster, and background graphics are now updated. The sound is updated-particularly percussion and strings. It has all of the abilities and items that were dummied out from the FFIIUS version.
The plot is clear, crisp, and comprehendable.
You can now change party members near the end of the game-hurray.
There are lots of new weapons and armors found in the two new (and pretty long) dungeons.

Thanks for the answers guys. That actualy helps me out.