Inline assembly

/me checks optimizations bookmarks
THE book on ASM(Art of assembly)

SSE/3dnow instruction set documented really well

Ok for asm, but don''t take everything at face value

The first two are the best. I don''t have anything on inline asm in particular, but all you have to do is:
__asm {
insert cool asm code here
}

You can reference variables in your inline asm block.

Anyway, hope those help

Oh yeah, and lemme point out some things ANYONE that wants to optimize should look at before asm:

You did profile, right? If you''re using c++, make sure that object allocations are about what you were expecting. Don''t do stupid stuff like pass by value for non-trivial structs. Pull common definitions out of loops(don''t recompute a value in each iteration if it is constant for all the iterations). Make sure you''ve turned on compiler optimizations =)

Use display lists or glDrawElements rather than glVertex calls if you use OpenGL.

You did profile right? Profile, profile, profile. This is very important!