Key concepts to learn in Assembly

Question

I am a firm believer in the idea that one of the most important things you get from learning a new language is not how to use a new language, but the knowledge of concepts that you get from it. I am not asking how important or useful you think Assembly is, nor do I care if I never use it in any of my real projects.

What I want to know is what concepts of Assembly do you think are most important for any general programmer to know? It doesn't have to be directly related to Assembly - it can also be something that you feel the typical programmer who spends all their time in higher-level languages would not understand or takes for granted, such as the CPU cache.

Answer 1

Register allocation and management

Assembly gives you a very good idea of how many variables (machine-word-sized integers) the CPU can juggle simultaneously. If you can break your loops down so that they involve only a few temporary variables, they'll all fit in registers. If not, your loop will run slowly as things get swapped out to memory.

This has really helped me with my C coding. I try to make all loops tight and simple, with as little spaghetti as possible.

x86 is dumb

Learning several assembly languages has made me realize how lame the x86 instruction set is. Variable-length instructions? Hard-to-predict timing? Non-orthogonal addressing modes? Ugh.

The world would be better if we all ran MIPS, I think, or even ARM or PowerPC :-) Or rather, if Intel/AMD took their semiconductor expertise and used it to make multi-core, ultra-fast, ultra-cheap MIPS processors instead of x86 processors with all of those redeeming qualities.