Grzyb wrote on 2021-02-12, 22:48:Come to think of it... […]
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Come to think of it...
Even with an FPU, floating-point instructions are slower than integer instructions, right?
Floating-point is only good when precision is important.
And games weren't about precision, games were about speed - so it was all based on simplified, integer-only math.
You think of FractInt, the famous Mandelbrot generator, don't you? 😉
It's written in 32-Bit assembly and uses integers favorable..
FPU instructions are usually executed very quick (few cycles) , because an FPU is very good at math.
Normal processors are very bad at mathematics, actually.
They are not "computing", but rather compairing on a logic level. AND, NAND, OR, XOR etc.
A classic ALU (a main part of a CPU) can only know two types of calculation. Addition (+) and subtraction (-).
Any other type, like multiplication (* or x) and division (: or /) must be implemented using these two.
Anyway, many math teachers at school either not know that or tend to forget it (for ages).
Equally ironic is the fields of programming, also.
People good in math are not necessarily very good in programming.
Math teachers argue how good these people /pupils are in logical thinking and that they fit the computing business so very well.
However, language and writing skills are actual more required.
Unless someone works in machine language, programs are being written.
People good in grammar or language/communications may benefit here.
(Also, the foundation of modern technology, the radio/wireless technology, was all about music/communications.)
I guess that's why in the past many women also successfully operated mainframes or entered data on the terminals, despite the stereotypic "women are bad at math" thing. 😉
Re: Software for testing math-co (8087) ?
DNSDies wrote on 2021-02-12, 19:14:Because math co-pros cost like $2000+ back in the day.
They were nearly as much as an entire computer. […]
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Because math co-pros cost like $2000+ back in the day.
They were nearly as much as an entire computer.
No developer wants to lock people out of a game for not having a $2000 piece of equipment with limited functionality and little or no real-world use in games.
*cough*RTX*COUGH*
That's true, but there was a market of free and cheap FPU software emulators, too.
The same floating-point code written for the real thing was able to run on these emulators.
And even if no FPU was available, many compilers had an FPU option that would include an 8087 emulation that would kick in automatically in case no FPU was installed.
Also, at the time, say '86/'87, it was foreseeable that FPUs would either drop in price or would become standard in the near future.
The 80486 was released in '89, but rumors of it's specs or a roadmap surely must have been cycling around for 1-2 years already.
FPU emulators..
For example, EM87 was public domain.
You could either get a copy of it from your computer dealer for a low price (say $5) or for free off a mailbox system/BBS, CompuServe, Fidonet, an university's database at the other end of the world via an X.25 connection.
Re: What are GOOD PC emulators ?
And then there were commercial FPU emulators. Like Franke387, which used 32-Bit code and was very fast.
Sometimes even outperforming 16-Bit FPU emulation code or floating-point libraries found in big compilers.
Yes, it did cost money (demo was available).
But not $2000, but more like $200.
And it surely made CAD/CAM programs, even the free/cheap ones, a noticeable bit quicker.
Errius wrote on 2021-02-13, 02:29:
I remember a text file called the 'co-processor faq' which used to be distributed on Usenet. Did anyone here save a copy? It explained all of this stuff in great detail.
http://www.cpu-collection.de/info/copro16a.txt
^This one? 😀
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