- James Madison was one of the Founding Fathers. He presided over the War of 1812, wherein much of Washington D.C. was burnt down; fortunately for him this happened after he had already been elected to a second term. Many things were named after him, including New York City’s Madison Square Garden. Also, there are brands of ice cream and snack cakes named after his wife, Dolley (a famous hostess).
- Understanding the x86’s Decimal Adjust after Addition (DAA) instruction (righto.com)
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.