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4 answers
80286 real mode emulator for 8086
While trying to use a "modern" sound card (an Aztech Sound Galaxy Pro 16 II) in an XT compatible 8086 computer, I encountered the problem that the drivers and tools (like the mixer initialization tool and the resource configuration tool) are…
Michael Karcher
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Oxford C compiler for Commodore 64
I kept one floppy from my Commodore 128 (which I used mostly in C64 mode), labelled ‘Oxford C compiler’. It is a 5.25″ floppy. Don't ask me why I kept just this one; probably because I thought I wanted not to keep a game but something ‘serious’. I…
Michel Keijzers
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19
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Why was Logo created?
The Logo programming language was created by researchers at MIT's AI Lab. Its post-1980s use has been predominately in the educational field, but is this what the language was originally designed for?
The PDP-11 assembly contains numerous references…
wizzwizz4
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19
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2 answers
Why were TECO variables called Q-registers?
The TECO editor, (originally Tape Editor and COrrector, later Text Editor...) found in some form on just about every computer and operating system DEC ever made, provides variables in which you can store numbers and/or text.
These variables are…
dave
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19
votes
3 answers
Commercial C64 software implemented in Forth?
There has been several implementations of Forth that were running on, and targeting, the C64. Were there any commercial software releases (not throw-away hobby projects or in-house utilities) that were implemented in such a Forth system? The more…
Cactus
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19
votes
3 answers
What was the role of Commodore-West Germany?
Most of the history of Commodore in personal computers took place while East and West Germany were divided, and Commodore maintained a significant corporate presence in West Germany. While I believe that the center for Commodore's R&D was Its…
Brian H
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19
votes
3 answers
How to switch an 80286 from protected to real mode?
It's pretty well documented how to get the 286 from real mode to its 16-bit protected mode.
It's also widely stated that the 286 had no officially supported way of going back from protected mode into real mode without losing its current state. The…
user
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19
votes
1 answer
What's the timeline of Motorola 6800-family CPUs from 1974 to 1979?
According to Wikipedia, The Motorola 6800 was released in 1974. Between that and the release of the 6809 in 1979 (or 1978?) there was at least one other 6800-series CPU released, the 6802 microcontroller with the same registers and instruction set…
cjs
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18
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1 answer
How to move sprites to the border on c64?
As far as I know, there is no register in the VIC-II, which would enable this.
Despite that, in nearly all intros and in many cases even in old games, sprites on the border were visible. Actually, it was the only way to put meaningful pixel images…
peterh
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18
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3 answers
Why does Sinclair BASIC have two formats for storing numbers in the same structure?
The ZX Spectrum has two formats for storing numbers, both 40 bits, or five bytes.
The first is a floating point format, which consists of one exponent byte, and four mantissa bytes. The first bit of the mantissa is assumed to be 1 and so is not…
Omar and Lorraine
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18
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2 answers
Cassette tape storage formats
I just came across this excellent article on cassette tape storage formats.
One thing confuses me though... in the "all digital" examples, like Figure 1C, what exactly ends up on the tape? That is, if I were to simply play the tape, what would I…
Maury Markowitz
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18
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1 answer
Inglish parser on the Hobbit (1982 video game)
Most adventure games, to keep the parser simple, might just have some simple rules, which accepts verb + noun or a cardinal direction, and simple things like that. That's almost a CFG, so in Backus-Naur Form, a simple parser might look like:
s =>…
Omar and Lorraine
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18
votes
5 answers
Why are different emulators needed to run platforms that use 6502 assembly code?
To my knowledge, an emulator turns machine code for a console into something that your computer can understand. For example, assembly code from a Gamecube game is not the same as from a .exe file.
That said, why are multiple emulators needed to run…
Jonathan O'Brady
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18
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1 answer
Which undocumented 8085 instructions is Steven Morse referring to in "In The Beginning"?
In S. P. Morse's 1980 allegory, "In The Beginning", he writes
And Intel said, "Let there be an 8085 with an oscillator on the same chip as the processor, and let an on-chip system controller separate the data from the control lines." And Intel…
Evan Carroll
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18
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2 answers
What does "jmp *" mean in 6502 assembly?
Right now I am learning 6502 assembly. Currently I am using the MADS assembler to program for the Atari 800. This program is just a small tutorial program that came with the assembler zip file I downloaded. The only piece of this program I did't…
user115898
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