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The Zilog Z80 has turned 50

goliath32.com

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Re: The Zilog Z80 has turned 50

#41

Post by KiwiJohnno »

ozhero wrote: post #7

I started programming in 1978 (In Assembler) and wanted to know not only how the software worked but how the hardware worked. Found a great kit using the Z80 and built it and spent many nights with a logic probe and oscilloscope learning digital eletronics. Also devoured the Z80 manual learning the instruction set. I'm nearly 70 now but remember those days like they were yesterday. Truly a magnificent CPU

May I suggest you check out the game "Turing Complete" https://turingcomplete.game/

It sounds like it may be right up your alley. Its a simplified digital logic simulator, you make basic circuits from NAND gates, and then build these into functional units in later levels, then further on you build an instruction decoder, and combine it with these functional units and before long you have a Turing complete architecture and you are writing your own assembly on it - Assembly language that you defined, from scratch. You'll find the need for new opcodes... so, you build them! Challenging game for sure, but very, very rewarding.

The game is still in early access, but very near a full release. They just put out a trailer: https://www.youtube.com/watch?v=goclUECM2ds

Re: The Zilog Z80 has turned 50

#42

Post by asdefghyk »

groos wrote: post #40

35 years ago I had to program a Z80 by "assembling" programs by hand and punching hexcodes into a board. This was made easier by writing an assembler for it. This was my way into tools which took me eventually to working on a major C++ compiler.

RE "....assembling programs by hand and punching hexcodes into a board......"

You translated you assembly language to machine language. ( Machine language is the only language a CPU can understand. )

Re: The Zilog Z80 has turned 50

#43

Post by TheOtherHobbes »

xcf_seetan wrote: post #29
YZF wrote: post #2

As the proud owner of a ZX-81 I remember staring at the Z80 instruction reference at the end of the user's manual without the faintest clue of what any of that meant. It took me some while before I managed to wrap my head around how CPUs actually run programs (vs. the high level abstractions like BASIC or other languages).

Another proud ZX-81 owner, my first computer bought as kit. It made me the TI pioneer in my little city. So cool times, everything was complex and simple at the same time. I had a flight simulator in only 1Kb ram :D

The ZX81's 1k chess - actually 672 bytes - was, and still is, legendary.

Re: The Zilog Z80 has turned 50

#44

Post by rahimnathwani »

asdefghyk wrote: post #42
groos wrote: post #40

35 years ago I had to program a Z80 by "assembling" programs by hand and punching hexcodes into a board. This was made easier by writing an assembler for it. This was my way into tools which took me eventually to working on a major C++ compiler.

RE "....assembling programs by hand and punching hexcodes into a board......" You translated you assembly language to machine language. ( Machine language is the only language a CPU can understand. )

Yes 'assembling' is exactly what GP did when they converted e.g. `LD A, B` into 0x78.

I wouldn't call it a 'translation'. It's encoding. (We don't think of converting between ASCII codes and symbols as translation.)

Re: The Zilog Z80 has turned 50

#45

Post by ColdStream »

groos wrote: post #40

35 years ago I had to program a Z80 by "assembling" programs by hand and punching hexcodes into a board. This was made easier by writing an assembler for it. This was my way into tools which took me eventually to working on a major C++ compiler.

Yeah but that would have been the late 70's... oh my gosh that was 1991!

It was cool to do that kind of stuff, you knew exactly what your program was doing (if all went right) at all times, but it sure was a slog to get anything complex moving.

Re: The Zilog Z80 has turned 50

#46

Post by decryption »

When I started TAFE (the equivalent of community college in the US I assume?) in Australia in 2003, one of the subjects in the electronic engineering course was to study and program a Z80. I was awful at it, but it was a good introduction to how a computer works. I wonder if they're still using this CPU as a way to teach the fundamentals of computers?

Re: The Zilog Z80 has turned 50

#48

Post by jenova-marie »

Happy Birthday Z80!!!!! My first little Timex computer! I was just thinking of you the other day in fact! Do you remember that terrible flight simulator we wrote in your BASIC, then discovering your assembly!!!! Yes, I remember, at 10 I was incapable of ASM, but that's why they made the 6502C years later!!!!! I still love you Z80, you did pop my cherry! I hope ur not still upset about that whole AIM-65 incident.....

Re: The Zilog Z80 has turned 50

#49

Post by kazinator »

tasty_freeze wrote: post #27

The article claims: > The Z80 is fully binary compatible with the 8080 instruction set. It wasn't in regards to the flag register. The parity flag behaved differently for some ops. And of course it would be possible to write an 8080 program that used undefined ops that would execute in some random way (often just duplicating an existing instruction) while the Z80 repurposed that opcode for something new.

But "undefined ops" are not part of the "8080 instruction set"; supporting those would be "binary compatible with the 8080 silicon".

The parity flag is a breaker though; "binary compatible for code only relying on the 8080 instruction set, other than values of the parity flag".

Re: The Zilog Z80 has turned 50

#50

Post by chasil »

ozhero wrote: post #7

I started programming in 1978 (In Assembler) and wanted to know not only how the software worked but how the hardware worked. Found a great kit using the Z80 and built it and spent many nights with a logic probe and oscilloscope learning digital eletronics. Also devoured the Z80 manual learning the instruction set. I'm nearly 70 now but remember those days like they were yesterday. Truly a magnificent CPU

Both the Z80 and the 6502 were products of corporate rejection.

I'd love to see another designer introduce a FORK86-64, but things are much more complex now.

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