Due to its simplicity it's a fun little processor to program. Hacking on some assembly on a ZX spectrum emulator is a nice way to stay sane in this high abstraction LLM age.
"Simple" is really not a word I would associate with the Z80 ;)
The ISA is quite messy because of the backward compatibility requirement with the Intel 8080 (e.g. the Z80 had to fill undocumented gaps in the 8080 opcode encoding map with new instructions, four of which were prefix instructions to unlock additional instruction 'subsets' (DD/FD for replacing instructions involving the HL register pair with indexed addressing modes via the IX/IY registers, and ED/CB prefixes for adding two entirely new opcode blocks).
If the Zilog engineers would have been free to design their own ISA I'm sure they would have been able to come up with a much more elegant design.
Also the Z80 had more than twice as many transistors as the 6502 (8500 for the Z80 vs 3500 for 6502).
I still prefer programming the Z80 over the 6502 though :)
I am simplifying a lot since there were much more chips involved... but 3500 transistors to have countless hours of fun to play NES games really puts things into perspective
My 5090 has 92 billion transistors (I dont say they dont bring fun)
Z80 was the choice of a microprocessor for then home computers such as Radio Shack TRS-80, SORD M23P, M5, Sinclair ZX81, ZX Spectrum, KayPro II, and many other manufacturers.3 It was capable of running the CP/M operating system in most Z80-based PCs. Z80 had a reasonable share in the PC market until Intel revealed its 16-bit microprocessor in the mid-1980s. Z80 was very popular as a microprocessor not only in PC applications, but also in industrial embedded applications, and some of the big manufacturers have Z80 core inside their ASIC chips still today or use enhanced versions of Z80 in consumer electronic devices.4–7 Zilog still manufactures ez80, an enhanced version of the original Z80, which is still being used by Texas Instruments in its TI-84 and TI-84 Plus calculators.7 It is among the few silicon chips that made a remarkable impact on the electronic device industry.8 To this day, Zilog produces a range of Z80-based microprocessors and intelligent peripheral controllers, and they are available from reputed electronics component suppliers.2,9,10 This microprocessor is one of the longest living microprocessors of all time.
Tom Jennings, the creator of fidenet, is producing a nice modern Z80 computer[0]
0. https://www.ebay.ie/itm/206496219323
(emulated)
interesting to be reminded that an 8080 (8 bit datapath) took 4,800 transistors
an Apple M5 Max is 100,000,000,000 transistors (ok it’s 18 CPU + 40 GPU cores) by comparison so 17 million 8080 equivalents
This is understandable, considering that the M5 is the Ultimate Computer, powered by Dr. Richard Daystrom's very own engrams
excellent point
Yup and Moore's law about transistors doubling every 18 to 24 months did basically hold, which is even more impressive.
Foreseen it was.
The ARM 1 only had 25,000 or so.
wonders how ARM did that - the MIPS R2000 came in at ~115k and the 80286 ~134k
anyway - say you want 50% of the transistors for on chip RAM these days, then thats
100 billion / 50 thousand = 2 million ARM 1s
clocking at say 3GHz
6e15 MIPS = 6 peta MIPS
so if you could run code on it, you would get a 10,000x speed up ;-)
A fairly deep dive into it
https://www.righto.com/2015/12/reverse-engineering-arm1-ance...
Due to its simplicity it's a fun little processor to program. Hacking on some assembly on a ZX spectrum emulator is a nice way to stay sane in this high abstraction LLM age.
"Simple" is really not a word I would associate with the Z80 ;)
The ISA is quite messy because of the backward compatibility requirement with the Intel 8080 (e.g. the Z80 had to fill undocumented gaps in the 8080 opcode encoding map with new instructions, four of which were prefix instructions to unlock additional instruction 'subsets' (DD/FD for replacing instructions involving the HL register pair with indexed addressing modes via the IX/IY registers, and ED/CB prefixes for adding two entirely new opcode blocks).
If the Zilog engineers would have been free to design their own ISA I'm sure they would have been able to come up with a much more elegant design.
Also the Z80 had more than twice as many transistors as the 6502 (8500 for the Z80 vs 3500 for 6502).
I still prefer programming the Z80 over the 6502 though :)
I am simplifying a lot since there were much more chips involved... but 3500 transistors to have countless hours of fun to play NES games really puts things into perspective
My 5090 has 92 billion transistors (I dont say they dont bring fun)
A paragrap from the linked articale
Z80 was the choice of a microprocessor for then home computers such as Radio Shack TRS-80, SORD M23P, M5, Sinclair ZX81, ZX Spectrum, KayPro II, and many other manufacturers.3 It was capable of running the CP/M operating system in most Z80-based PCs. Z80 had a reasonable share in the PC market until Intel revealed its 16-bit microprocessor in the mid-1980s. Z80 was very popular as a microprocessor not only in PC applications, but also in industrial embedded applications, and some of the big manufacturers have Z80 core inside their ASIC chips still today or use enhanced versions of Z80 in consumer electronic devices.4–7 Zilog still manufactures ez80, an enhanced version of the original Z80, which is still being used by Texas Instruments in its TI-84 and TI-84 Plus calculators.7 It is among the few silicon chips that made a remarkable impact on the electronic device industry.8 To this day, Zilog produces a range of Z80-based microprocessors and intelligent peripheral controllers, and they are available from reputed electronics component suppliers.2,9,10 This microprocessor is one of the longest living microprocessors of all time.
Slop from the article
Ironically (and sadly) the Z80 was discontinued not very long after this piece was published.
I'm sure clones are still being made.
The cpu possibly, but I had a hard time trying to find the support chips (ctc, sio/pio, etc)...