[pcwalton]

Just a couple of annoying nitpicks:

> * Most operations on registers, like addition and subtraction, have the side effect of altering status flags, like "the last value computed resulted in zero". There are just a few status flags, and they usually live in a special register.

Note that this is a CISCism. Most RISC designs, like ARM, allow the compiler to specify whether condition codes are to be updated in order to more easily eliminate false dependencies.

> * A CALL is just an unconditional GOTO that pushes the next address on the stack, so a RET instruction can later pop it off and keep going where the CALL left off.

Also a CISCism. Most RISC designs have a "link register" that the return address goes into, and the stack push, if desired, has to be done manually. RET is, in this case, just an unconditional branch to the address in LR.

[tptacek]

These aren't true of MSP430 or AVR, both of which are RISC-ish designs. Also, you still have to save the link register inside functions that call other functions. I also didn't explain SPARC register windows. :)

But hopefully these nitpicks aren't so much "annoying" as they are an example of how little you need to know to follow a discussion about super nitpicky details of different architectures. AVR has a general-purpose programmable condition flag 'T' in its status register. What do you do with the 'T' flag? I'unno, but hopefully the basic idea makes sense after not- too- much reading!