On Fri, 20 Jul 2007, gramlich wrote: > Another question along these lines. What's the difference between 32-bit > assembly and 64-bit assembly for x86? Are the 64-bit instructions a > superset or are there other changes I should be aware of? Well, the main difference is that registers now are 64 bits wide, instead of just 32 bits wide. There are also 8 new registers, plus a couple of new addressing modes (to allow you to manipulate 32-bit data in 64-bit more), and some other minor details. But AMD's 64-bit extension is about as unobtrusive as you could have hoped for. At the level you're at, there isn't much of a difference. The ideas are still the same. Brian