How did the Z80 instruction set differ from the 8080?
Oct 26, 2016 · The Zilog Z80 microprocessor, known for its use in the ZX Spectrum, was designed to be a backwards-compatible extension to the Intel 8080 processor. It introduced several new instructions …
Comparing raw performance of the Z80 and the 6502
May 21, 2022 · The Z80's fastest memory fetch — the first half of an operation fetch — takes two cycles. That's always paired with another two cycles for refresh though, so the shortest instructions are four …
How do Z80 Block Transfer instructions work?
Jan 12, 2018 · The Z80 already had quite a high transistor count for the time. Implementing the ***R instructions the efficient way would have required implementing looping and/or branching logic in the …
z80 - What is R register and DRAM refresh internal operation ...
Apr 14, 2024 · The Z80 CPU has a built-in feature to support refreshing DRAM memory, by keeping a 7-bit refresh counter in the register R. The refresh counter is increased by 1 after every instruction …
z80 - Decoding Logic and Memory Systems for 8-bit computer - 64K ...
Apr 27, 2020 · I am creating a minimal Z80 computer with serial output on a breadboard. I have kind of moved up from the last question, where I was executing instructions on Z80 using specific …
Why do C to Z80 compilers produce poor code?
Mar 29, 2018 · The Z80 has 6 (ish), and 2 of those basically have to be reserved for use as a pointer for almost all nontrivial code. This gives compilers for those architectures a lot more scope to optimize.
What was the last commercial Z80-based computer sold?
Jul 13, 2025 · AFAICT, the last Z80 desktop computer sold was the TRS-80 Model 4, in production until late 1991. If you include notebook computers, the Amstrad NC200 was released in 1993.
Did underclocking the early Z80 chips improve yield?
Nov 16, 2022 · The Z80, one of the most successful and well-known of the 8-bit microprocessors, was released in July 1976 at an initial clock speed of 2.5 MHz. The TRS-80 Model I, released the …
Managing registers/memory effectively on the Z80
Feb 17, 2023 · The Z80 assembler unified the mnemonics to a great extent. Its rather abstract angle simplifies first steps. In contrast 8080 mnemonics are more diverse, if not chatty, presenting more of …
Why is Z80 called a 8-bit CPU? - Retrocomputing Stack Exchange
Mar 17, 2024 · The Z80 fetches, processes and stores 8 bit at a time. Z80 has a 16-bit address bus If address bus would be a relevant measure to classify a CPU, then 8088 would be not 16 but 20 bit …