asm mode doesn't recognize gas comments...

[Brendan Miller]

By default it seems that asm mode recognizes MASM style comments
(starting with ;), but not gas style comments (starting with #). A
little weird for a GNU program running on Linux...

Anyway, according to asm modes docs:
http://www.phys.ufl.edu/docs/emacs/emacs_299.html

asm-comment-char can be set. So I added this to my .emacs:

(set 'asm-comment-char "#")

This makes ; stop highlighting like a comment, but doesn't make # do
anything. Am I doing anything obviously wrong? Is there some mode file
somewhere that actually handles the GNU assembler syntax?

Brendan