From: "Chuck Guzis" <cclist at sydex.com> It's a problem with instruction sets that implement result codes as a simple condition code register. The same arithmetic that couints interations affects the condition codes that one might also need for searching or computation. That's probably the reason that the increment and decrement instructions don't bother the carry flag and that the 16-bit increments and decrements on the 8080 didn't bother any of the condition codes. Inspection of the 808x instruction set can be very illuminiating, particularly when it comes to arcana like which instructions modify (and how) the half-carry flag, for example. Cheers, Chuck