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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7
votes
1answer
429 views

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 ...
8
votes
3answers
536 views

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 ...
16
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4answers
2k views

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 ...
20
votes
11answers
5k views

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 ...
9
votes
2answers
713 views

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 ...
18
votes
4answers
1k views

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 - ...
23
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8answers
5k views

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 ...
-3
votes
2answers
391 views

How can 8bits = 1byte but also = 255 bytes at the same time? [closed]

I don't understand why 8bits is defined as being equal to 1byte or 1octet but at the same time the maximum capacity of an 8bit bus or 8bit databus would be 255 bytes because 128 64 32 16 8 4 2 1 1 1 ...
8
votes
1answer
806 views

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 ...
10
votes
8answers
2k views

Were there any bitmap-based 8080 computers?

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 ...
20
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17answers
5k views

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 ...
27
votes
1answer
2k views

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 $ ...
6
votes
2answers
796 views

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 ...
5
votes
4answers
627 views

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 ...
2
votes
1answer
110 views

TMS9918ANL question

I am working on setting up a TMS9918ANL Video Display Processor. I was wondering if there is any way I can test to see if it is working without having the DRAM hooked up (I have a while before the ...
3
votes
1answer
257 views

What bug in first version of game Karateka for Apple 2e cause this game reset in Apple 2c?

If I try to start the first version of the game Karateka for Apple IIe on an Apple IIc, the Apple IIc will restart after reading the game from disk after a few seconds. Later versions of Karateka for ...
3
votes
4answers
569 views

“SAP” microcomputers vs real microcomputers

In Paul Malvino's "Digital Computer Electronics", he labeled 3 theoretical microcomputers which he called the SAPs or "Simple As Possible"s. The point of these 8-bit microcomputers was to teach ...
24
votes
9answers
7k views

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-alike keywords, 3) Prompt-Command-Parameters pattern interface. Why was ...
19
votes
4answers
5k views

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 ...
30
votes
2answers
5k views

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)...
2
votes
4answers
362 views

What 8bit home computers did not have a supplied intro tape [closed]

As per the title, we are obviously referring to machines that had cassette audio tape as their default medium even if other media was supported via expansion. To be clear I mean what was "in the box" ...
21
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9answers
5k views

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 ...
15
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3answers
3k views

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 ...
5
votes
5answers
740 views

Did any assemblers work like this?

Once you get past the stage of manually entering numeric machine code, the most primitive programming tool is a machine code monitor. Intended primarily as a debugging tool, this works with a target ...
13
votes
10answers
3k views

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) ...
75
votes
12answers
17k views

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 ...
20
votes
4answers
5k views

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 ...
10
votes
6answers
2k views

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 ...
5
votes
4answers
2k views

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 ...
8
votes
3answers
1k views

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 ...
9
votes
3answers
2k views

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 ...
11
votes
12answers
2k views

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 ...
52
votes
12answers
13k views

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 ...
9
votes
3answers
3k views

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 ...
18
votes
3answers
992 views

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 ...
1
vote
1answer
370 views

How to I give instructions to a Z80 CPU [duplicate]

I found a Z80 CPU lying around my house. I've search all over the Internet but I still don't know how do I input stuff and tell it what to do. Help me please
21
votes
3answers
6k views

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 ...
24
votes
6answers
11k views

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?
15
votes
6answers
724 views

Did any microcomputers back in the day accellerate 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,...
6
votes
5answers
831 views

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 ...