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17
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4 answers
Why was the Amstrad CPC slow at scrolling
As I understand, neither the Amstrad CPC or the Sinclair Spectrum had any support for hardware scrolling, and arcade conversions struggled compared to the C64 or NES.
However, isometric 3D games such as 'The Great Escape' leveraged the fast Z80…
Mark Williams
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17
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What limited the use of the Z8000 (vs. 68K and 8086) CPU for 16-bit computers?
As compared with the 68000, which also was available from 1979, and which also started off quite popular in desktop-sized UNIX machines, it apparently has a much more sophisticated memory model, which I suppose means that process isolation etc would…
Omar and Lorraine
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17
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2 answers
Why was the 6809 so expensive?
The 6809 was released in 1978, but looking at the usual source for price quotes for old computer components, Byte magazine, I cannot find any quotes for 1979. December 1980 lists it at $38, compared to its closest competitor, the Z80A, for…
rwallace
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17
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2 answers
Is WinWorldPC legal?
I'm sure a lot of us have come across WinWorldPC online. With the valuable resources that it has for obsolete systems, is it actually legal? For example, I could download almost any Windows system I wanted (theoretically) that came out earlier than…
Retro Gamer
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17
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2 answers
History of the demise of Matrox from the world of 3D graphics cards
In the last century, a brand of video cards that rhymed with quality, Matrox, was very popular and the choice for professional applications and to some extent for 3D gaming.
The benefits of upgrading your computer with a Matrox Millenium were…
Eric Cartman
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17
votes
2 answers
Name this PC DOS Combat Flight Simulator
I'm trying to remember the name of a PC DOS Combat Flight Simulator that I played around 1991/92. I can give the following details:
It was named after a US fighter plane that would have been in active service during the 1980's and 1990's.
It ran…
pmarflee
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17
votes
2 answers
6502 branch offset calculation
This question expands on How does the 6502 implement its branch instructions?
I'm working on a cycle accurate VHDL implementation on an FPGA. I have much of the program logic already written, but I can't wrap my head around how to logically…
Evan
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17
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3 answers
x86 as a Pascal Machine?
From this answer by gsg about the usage of certain x86 instructions:
Note that the x86 was originally designed as a Pascal machine, which is why there are instructions to support nested functions (enter, leave), the pascal calling convention in…
Evan Carroll
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17
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4 answers
How can I run COMIT code?
I recently learned about the existence of COMIT, which was the first string processing language. It's very old (1957), but it was used a lot in the first 10 years it was around, mainly in academic research. Eventually, it fell into obscurity.
It…
Laurel
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How to create a switchless multi-system 2 button Atari joystick?
All systems that use the Atari 9 pin joystick standard make use of the following pins in consistent ways, with each direction and the fire button being connected to the ground pin when pushed.
1 - up
2 - down
3 - left
4 - right
6 - fire
8 -…
Paul Humphreys
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17
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2 answers
Is the s-video output on the Commodore 64 different from "normal" s-video?
I saw Commodore 64 to modern TV about how to connect the Commodore 64 to a modern TV. I don't understand all the details of the answer, so I wanted to try and ask something specific here.
In short, I just got a Commodore 64C and I have a VGA…
Thomas
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17
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3 answers
Why do only the low 7-bits of the R register increment?
On the Z80 the R register is 8 bits wide, as evidenced by LD A,R and LD R,A And every M1 cycle, R increments by 1. But the uppermost bit does not participate in this increment. R will not go from 0x7F to 0x80 or from 0xFF to 0x00. Apparently that…
Omar and Lorraine
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17
votes
3 answers
What is the relationship between solid-state ROM and inaccessible content in arcade games?
I was browsing through tcrf.net, which specializes in displaying unused programming and content left in games by developers, and came across this page:
https://tcrf.net/Tank
Specifically, the following paragraph:
Tank is the first known arcade game…
GGMG-he-him
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17
votes
4 answers
Mind-Controller User Input from the late 90s
In the late 1990's, I recall that there was a piece of hardware being demonstrated in Best Buy that supposedly allowed you to control your computer via signals sent from your brain.
The way it worked was that there was a small metallic plate that…
phyrfox
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17
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9 answers
Z80 and video chip contending for random access
Back in the 8-bit days, I used 6502 computers, where the story about memory access was easy to understand. RAM chips of the late seventies and early eighties could do 2 MHz (or a bit more e.g. 2.6 in the datasheet I found), a 1 MHz 6502 took half…
rwallace
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