Questions tagged [8-bit-microcomputers]
For generic questions about 8-bit microcomputers. For specific computers please use the appropriate specific tag.
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Back in the late 1980s, how was commercial software for 8-bit home computers developed?
When hobbyists wanted to write software for e.g. the Commodore 64, they either used the built-in BASIC interpreter (with all its limitations) or some native tools, like compilers for other languages ...
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How was the first assembler for a new home computer platform written?
How did the 8-bit computers (Spectrum, Commodore, Atari, Amstrad etc) typically "bootstrap" from bare electronics into a platform with a working assembly language and OS?
What I mean: An assembler is ...
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What made some 8-bit BASIC interpreters especially slow?
Most 8-bit systems had a BASIC interpreter that ran at a rate roughly commensurate with the CPU type, speed, memory bandwidth and interrupt status. Some systems, however, had interpreters that ran at ...
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Did John Carmack really invent "Adaptive Tile Refresh"?
John Carmack is credited with making fast-paced arcade games like Commander Keen possible on an IBM-PC that had no specialized graphics controllers suited for those, thanks to the "Adaptive Tile ...
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When and where did the $ convention for hexadecimal literals originate?
I found this question asking about the origin of 0x to denote hexadecimal to be interesting.
However, when I cut my teeth programming on 8-bit 65xx systems in the early 80's everything I saw used a $ ...
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Why did 8-bit computers choose BASIC dialects as "de facto" command-line interface, instead of contemporary Shell/Lisp dialects?
While all three clans of languages predated 8-bit computers, they shares features like 1) imperative programming, 2) English-like keywords, 3) Prompt-Command-Parameters pattern interface. Why was ...
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Zilog Z80 freezes while binary counting up to 65 536 (2^16)
A few days ago, I got Z80A CPU from eBay. So I tried to run it with classic 555 timer as a clock signal generator. I connected the 8-bit data bus of the CPU to the ground to "simulate ROM" (00 for NOP)...
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Fastest 8-bit microprocessor for multiply-accumulate?
I'm wanting to identify which 8-bit microprocessor would have the best performance for a multiply-accumulate operation.
By "operation", I mean the minimal implementation for 16-bit operands ...
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Why did 8-bit Basic use 40-bit floating point?
Nowadays floating point is usually either 32 or 64 bits, sometimes 16, occasionally 128. But of course, the Basic interpreters on the 8-bit machines, having to implement floating point in software ...
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How common was programming in C targeting 8-bit processors in 1983?
How often was C used to program firmware for 8-bit processors in the early 80s?
I'm reverse engineering a firmware binary for a device built around a Hitachi 6303 processor, manufactured in 1983. Even ...
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Can x86 processors run 8-bit applications?
I was wondering if it is possible to run 8-bit applications within QEMU. I know that the x86 architecture can run 16-bit applications, but can it also run 8-bit applications?
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Which (micro) computers were dominant in Australia and New Zealand in the 1980s?
Australia and New Zealand are somewhat unique among large, developed, economies because they bridge the culture of (mostly) the West with the geography of the East. I am curious how this may have ...
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Wiring a Zilog Z80
I've recently got hold of an old Zilog Z80 microprocessor and I know how to clock and test it. I do not however know how to connect RAM, I/O ports, control switches (for programming instructions into ...
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8-bit home computers without BASIC
All the 8 bit home computers I'm aware of, had BASIC in their ROMs. A notable exception was Jupiter Ace, a British home computer which used Forth.
Were there any other 8-bit home computers that came ...
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Did any European computers use 10-line fonts?
Most 8-bit computers implemented hardware text mode, and most of those used 8x8 fonts. This was logical for American computers; the title safe area on NTSC is about 200 scan lines; font height 8 gets ...
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How did old computers address far more than 64K of memory despite only having a 16 bit address bus?
I have an old Sharp PC-G830 pocket computer from the '80s that has 32K of RAM and 256K of ROM. I also have a simple single board computer I built with 128K of RAM and a few megabytes of ROM from a ...
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Intel 8080-based home computers
I'd like to build an FPGA replica of a home computer based on the Intel 8080. I am not looking to design my own computer, since I would like to tap into an existing software base.
Were there any ...
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What LISP compilers and interpreters were available for 8-bit machines?
What LISP or LISP-like language compilers and interpreters were available for 8-bit microcomputers? Criteria for "8-bit" include that it should certainly run and execute non-trivial programs given no ...
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Were there any 8-bit CPUs with 24-bit addressing?
Or was that something that didn't appear until later CPUs (around the time of the 286 maybe)?
Also, how would I go about researching this on my own? It's not exactly something I can look up on ...
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Did any microcomputers back in the day accelerate standard-cassette performance
Many commonplace cassette recorders in the 1970s and 1980s were capable of reading or writing two tracks at once (stereo). While that wasn't universal (portable cassette recorders were often monaural,...
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Unlicensed home computer ports of arcade games
During the 1980s, it was quite common to see unofficial ports of popular arcade games released on home computer systems. For instance, Acornsoft (the software division of Acorn Computers) released ...
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How was the main mechanic of the game Qix implemented?
Qix was a quite unique Taito arcade video game that saw ports to nearly any home computing platform of its time. At first glance, the game mechanics seem to be targeted at low-performance hardware - ...
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Which 8 bit computer could display the most colors?
Which 8-bit computer could / can display the most colours on screen?
Please take into account undocumented/newly discovered video modes and other hacks. For example, static sprites supposedly allow ...
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Benchmark test that was used to characterize an 8-bit CPU?
I was curious if there was a benchmark test that was available to compare CPUs that are 8-bit. People always like meaningless analysis to justify some decision, and I was curious if there was a ...
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Which microcomputer manufacturers developed their own Local Area Network systems? [closed]
With the advent of microcomputers, there was a large number of manufacturers entering the home computer market. The ability to network these computers together wouldn't be very useful (or affordable) ...
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Copying tapes "back in the day"
Back when I had a ZX Spectrum 48K, I had a friend that had a 128K and we would swap games for the weekend from time to time.
We did try and make duplicates of the tapes (yes, I know, but we were ten ...
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How did Altair 8800 interrupts work?
I'm playing around with building an Altair 8800 emulator in my free time in C#. I've read through the Operator's Manual many times in the past, and I'm refreshing my memory of late.
I'm struggling to ...
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Emulators running on 8-bit personal computers
Were there emulators running on 8-bit computers (preferably "mainstream" personal ones), available to general public (as opposed to in-house developers only)? I am mostly after emulators ...
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Were there any 8080 computers that used a bitmapped display?
Does anyone know of any bitmap-based 8080/8085 (or, failing that, Z80) computers?
Background: In the late 70s and early 80s, there were a few hobby computers with bitmapped displays. For example, the ...
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Was there ever a microcomputer with a full-size keyboard and a hex numpad?
I'm aware of some early/super hobbyist microcomputers that came with ONLY a hex numpad (that is, no letters beyond F/no punctuation). I'm also aware of home microcomputers that had the usual decimal ...
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Did any 8-bit CPUs use dynamic memory for registers?
According to https://jamiestarling.com/project-8088-the-8088-cpu-pinout/
One thing to note – the 8088 registers are made from dynamic memory cells – they have to be refreshed. The minimum clock speed ...
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Testing "8-bit readiness" with an emulator or pre-packaged kit
I'm working on a project that intends to implement a dynamically typed language on 8-bit systems. (That is, a CPU with 16-bit pointers and a maximum of 64 kB of RAM. Some language tricks are involved, ...
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Do I have to use an 8284 chip with the 8088?
I recently got the idea to start an 8088 system because I've been really interested in retro computing and the idea of a "breadboard computer" sounds very fun.
From what I've read, every homebrew ...
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What "Write your own RPG/Adventure game" books were available for 8-bit computers? [closed]
During the 70s and 80s there were a number of books about how to write your own games for 8-bit computers, usually in BASIC. Three examples of these books are How to Create Adventure Games by ...
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BASIC : POKE and PEEK prohibited on the same line?
Having been raised on an 8-bit Commodore, I was never afraid of PEEKs and POKEs.
I remember trying to accomplish something on a computer, in BASIC, using PEEKs and POKEs, and discovering that this ...
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What kind of 256 color palette did the Enterprise 64/128 have?
The Enterprise 64 or 128 Home Computer apparently had a palette of 256 colors.
However, that is pretty unusual and doesn't fit evenly into the typical 3 channels for RGB. Wikipedia doesn't provide any ...
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Systems that used the Rockwell R65C00/21 or R65C29
The Rockwell R65C00/21 and R65C29 are described in an October 1984 datasheet ("R65C00/21 dual CMOS microcomputer and R65C29 dual CMOS microprocessor," Document no. 29651N64, rev. 2) which is ...
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Uh, oh, I've woken up in 1973. Can I get a job in computing? [closed]
I've woken up in 1973. Until I can figure out how to monetize my knowledge of coming political, economic, and social trends, I need to support myself somehow.
So... I walk into one of the major ...
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What were MECC's specifications for a school computer in 1978?
It is well-known that one key moment for Apple was selling 500 Apple IIs to the Minnesota school system in 1978.
I came across this video which discusses the background to that, including a reminder ...
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What was a MicroAce?
I am familiar with the original ZX80 and its "cousin", the Jupiter Ace, a similarly specc'ed machine but running Forth rather than BASIC.
However, a colleague at work stated that there had ...
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Looking for an 8-bit microcomputer with a hardware-accelerated database
In some old video on YouTube a few years ago, I noticed a curious computer from the end of the 70s - early 80s. In the rack (half height), typical of minicomputers of those years, there was a 14" ...
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Would some BASIC interpreters for microcomputers be considered operating systems?
As software for micros developed, you could use the BASIC interpreter just to CLOAD and RUN assembly language programs. Those might call BASIC ROM routines (say, for converting ASCII input to binary ...
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The proper way to shift a byte using a Z80
In a nutshell, why can I not shift a byte using this way?
LD A, 11110000b ; I want this to be 00001111b
LD C, 4
SRA C
OUT (0), A ; doesn't give correct number
What is the proper way of shifting a ...
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Commodore 8-bit character sets
Is the character set format same on every Commodore 8-bit computer or are there any character size, character order, or other differences between the machines?
I'm purely interested in the character ...
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Anyone have the 1975 edition of "An Introduction to Microcomputers, Vol 2"?
I'm looking for references to the EA9002, an ill-fated design if there ever was.
Practically the only place I can find it detailed is Osborne's Introduction to Microcomputers, where it was chapter 11 ...
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Is there really any implementation of a Ada compiler/cross-compiler/interpreter for 6502?
I found some Ada compilers for CP/M machines but no luck for 6502-based C64/Apple II/BBC Micro. I'm not sure if Abacus Ada on C64 exists or how much a subset it implements for Ada.
There is, though, ...
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Does a market/shop with fully legal 8-bit software/games exist? [closed]
Currently about all of "8-bit micro" games that I know is either abandonware (which is a gray area) or free fan works. But is there some kind of shop, market, some place where you can purchase these ...
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What was the first microcomputer capable of working with Japanese kanji?
Apparently the first microcomputer capable of working with the Chinese language in Chinese characters was the Microprofessor II (or MPF-II-C), a Taiwanese Apple II clone from 1982.
Now I'm 99% sure ...
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How does memory addressing/mapping work in 8-bit systems?
If I attach a 16 KIB EEPROM to a 6502 or similar, and put some kind of operating system on it, it will run fine, but won't have access to any other chips. So, when a Commodore VIC20 had 5k of ram and ...
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Did any 8-bit machine select palette by character name instead of color memory?
8-bit home computers, and contemporary third-generation consoles, commonly displayed graphics with an array of character cells, a.k.a. character names, character pointers, name table etc, each of ...
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