decimal adjust after addition instruction of
- I’ve been looking at the DAA machine instruction on x86 processors, a special instruction for binary-coded decimal arithmetic. Intel’s manuals document each instruction in detail, but the DAA description doesn’t make much sense. I ran an extensive assembly-language test of DAA on a real machine to determine exactly how the instruction behaves. In this blog post, I explain how the instruction works, in case anyone wants a better understanding.
- XOR (chiark.greenend.org.uk)
So I collected some thoughts together and gave a lecture on XOR. Slightly to my own surprise, I was able to spend a full hour talking about it – and then over the course of the next couple of weeks I remembered several other things I could usefully have mentioned.