On 4/22/24 08:36, Lamar Owen via cctalk wrote: > Die real estate forced the design to do without a full 8-bit ALU. When > you have a 4-bit ALU, and you are doing 16-bit math, you will need 4 > cycles through the ALU.
I don't know if this applies to the Z80, but on the 8080, 16-bit increment/decrement is handled by a separate increment block (also used to advance the P-counter and stack operations). Probably one of the reasons that INX/DCX doesn't set any flags. --Chuck
