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 …
Why did the Z80 with 4-bit ALU out-perform the fully 8-bit Intel …
Feb 16, 2020 · Looking at the development and architecture of the Z80, it appears to be a scaled-down, cost-reduced (in terms of total system cost), clone of the Intel 8080. It only used a 4-bit …
Comparing raw performance of the Z80 and the 6502
May 21, 2022 · It is said the Z80 has a typical 4 clock ticks per instruction, while the 6502 has typically 1 clock tick per instruction and a rudimentary pipeline. It is said the Z80 ALU …
Did underclocking the early Z80 chips improve yield?
Nov 16, 2022 · On the Z80, a complete M1 cycle takes two clock periods for a code fetch and two cycles for a refresh, while other accesses take three clock periods. If one subtracts out …
Did anyone ever use the extra set of registers on the Z80?
Oct 1, 2018 · The Z80 design was quite focused on a more flexible, configurable and faster interrupt handling than the 8080. though I think if I were programming a Z80 retro computer, I …
z80 - What is the relative code density of 8-bit microprocessors ...
Aug 13, 2017 · Z80 code to copy e.g. 57 bytes from one fixed address to another will take 11 bytes. 6502 code to do likewise will also take 11 bytes. The Z80's 11-byte copy technique will …
When did the Z80 compatibles reach very high clock speed?
Considering that it got about 4 times the thruput per clock as a genuine Z80, this would set it at a 200 MHz equivalent. As a (more or less) seperate CPU, that'S the top notch Z80 code can run …
z80 - How did 8 bit processors perform 16 bit arithmetic ...
Jun 5, 2018 · The Z80 includes two ALUs: a 4-bit general-purpose one, and a 16-bit increment/decrement circuit. Having recently found out about that, I find myself curious how …
history - In the original Z80 layout, where are the "traps" located ...
May 29, 2019 · According to Zilog Oral History, Zilog only had a tight schedule to design the Z80.Facing the potential competition, Federico Faggin and Masatoshi Shima were worrying …
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 …