On 4/22/24 12:18, Chuck Guzis via cctalk wrote:
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.
16-bit INC and DEC are indeed handled by a separate block, which also gets used to increment PC and decrement SP at the appropriate times.  Ken's page on the 4-bit ALU has a 'mapped' dieshot showing it. Ken covers it operation in the blog article https://www.righto.com/2013/11/the-z-80s-16-bit-incrementdecrement.html

Reply via email to