Need explanation of the CPU and FPU technology on turbo boards

[kidkoala]

I have a few questions about cpu's on accelerators;

I have a cd32 with sx32mk2 (think it's a 40Mhz cpu), I bought a fpu@33mhz, and i bought a crystal@33mhz as well.
Now, can you people explain to me;

1. what is the connection between the fpu and the crystal? (something about synchronous/asynchronous?), and can i just put in the fastest fpu and crystal there is? (says something about max. 33mhz in my primitive papers on the sx32).

2. can i put in the fastest cpu i find? (like a 50mhz or something), is there a connection between the cpu and the fpu speed?

3. what commands or programs do i use to find out the speeds that are right now? and how do i overclock the cpu/fpu?

4. what is the fpu used for (i know about floating-point operations, but what is that, and give me some examples of which programs/games use it and which doesn't)?

hope someone wants to answer all this, please give thorough answers if you do:) thanks a lot!

[kidkoala]

thank you all for the quick reply!

that made it a bit clearer..

[kidkoala]

well certainly I didn't expect such thorough and detailed answers

thanks a lot, though you're loosing me on the topic of "the
math instructions of the 68k"

[kidkoala]

here is an interesting article from the year of the lord 1999, considering the effects of an fpu, though in cooperation with three different patches;

http://www.youngmonkey.ca/nose/articles/NewTekniques_9902/ImprovingPerformance/index.html

[kidkoala]

haha, this is turning into a good laugh at 04:16gmt+1..

mad scientists growling, screaming, twisting thumbs and ripping out hairs; "what in the name of Jay Miner is that FPU good for!? why is it there? what can it do? who invented it and does it contain the meaning of life?!"

yes, i was also blown away by the monkey-link, and the other links from the same page, lots of very useful info:)

i'm always careful with conspiracy-theories, but those patches look a bit weird "we make a patch, and then we make a testprogram that shows some numbers that look very positive, and then we take money for giving these two programs to people" ..i don't know, probably was something useful for someone, i'll dig some more dirt about the use of an fpu


EDIT:
"Special programs (Raytracing, DTP, Mathematics, TeX) are offered in a special coprocessor version which are up to 50 times faster than the original versions. "

are dtp and tex programs?

[kidkoala]

haha cd, dir...use fpu an mmu?

I think the fpu would do the logic math, and arithmetic operations, that otherwise must be emulated on the cpu, or by the OS, if you don't have an fpu. but not like easy two-digit operations, but floating point operations with many decimals etc. I guess they have a pretty good fpu (or a few thousands) when calculating astronomy-things or astro-physics

Typical operations are floating point arithmetic (such as addition and multiplication), but some systems may be capable of performing exponential or trigonometric calculations as well (such as square roots or cosines).

Today, many CPUs/architectures have more than one FPU, such as the PowerPC 970.

x86 before the 80486 (from 8086), had either non fpu, or had a free optional slot, like on Amiga accelerator, for the 8087 (like a 68881/2).

[kidkoala]

@hyperspeed

thank you for the detailed info. which extends my last post to space and beyond

@alexh

I think it's like this: if you have a cpu@30mhz and a fpu@50mhz, then the fpu would have to wait for the cpu all the time, because it's so much faster.
it's better if they have about the same Mhz to cooperate better, meaning there's no point in having a really fast fpu if the cpu is lagging behind.

[kidkoala]

@amidude

hehe i think you just got scammed by the worst 1. of april-joke ever, and it's only the 26. of november (!)

nice list of fpu-programs! bring 'em on

[kidkoala]

i've counted about 20 programs that CAN, use the fpu here, and when it does use it, the program probably always gain very high calculation-speed, for what it need the fpu for, contra the speed without the fpu.

the point here is to find out what programs and games that can take use of the fpu, not that it's a higly needed thing that is vital to everyday use of a classic amiga.

if you haven't understood that by now, you need to read the whole thread over again, and you might also want to read a bit between the lines...

if you don't find the topic interesting at all, don't post

[kidkoala]

i guess you are one of those who need to read the thread over again

[kidkoala]

@karlos

"As far as I know, nothing in the standard OS install requires an FPU.

Only applications which need to do a lot of floating point calculation benefit are typically compiled to use an FPU; most normal apps make very little use of floating point and when they do, the mathieee libraries are usually enough. Said libraries can be replaced with FPU versions.

Lots of applications exist in versions which support an FPU if present but not many actually require them"

..most of us are aware of all of this, it is stated earlier in the thread as well, but your post about the details on how the fpu do math was very interesting!

by the way, i have a sx32 with a cpu@40mhz and a fpu@33 (i took it off because it seems to crash the accelerator).
but when i use the cpu-command in cli, in os3.9, it says 68020? is it the program that's wrong or does the cd32 somehow not use/enable the 68030?


@karlos

i guess demo-coders have a lot of the same knowledge to make good vector-programmed demos? does newer demos (say aga and up) use an fpu for the real-time calculations of vectors etc.?

[kidkoala]

@donnyemu

hehe that's fun to hear about..
i guess those early times, back in the 80's, was the birth of the use of a fpu, and that it wasn't very useful, because of non supported software and the slow architecture of the systems, like you said.
in the early 90' and beyond, the fpu got more and more useful, both in programs and games..so that for the period we talk about here (mainly the aga and newer) the fpu started to get interesting, and a couple of years later (when they put the fpu inside the cpu's, bot with motorola and intel) it was unthinkable not having one of these in a home-computer. it's a normal transition for a new component..

the period we talk about in this thread have some programs and games that take use of an fpu if it is there, and if the libraries are there, most of us knew that from before, and now we want to know which programs and games those are.
the performance, the usability etc. is another matter; but it is not the topic of this thread, we want to find out what can use it, then i think one has to prove it to themself on his or her's own equipment, cause clearly, no-one seems to have very concrete information or proof of this. hehe, that's why i started this thread cause i know a lot of people wonder what the fpu is good for, seen in a perspective with the amiga and it's software.

[kidkoala]

@amidude

read the posts, you are repeating me.

[kidkoala]

most people here know what you just said, and that is not what the thread is about, thus your last posts are worthless, annoying if you will other people here read the posts, so the already knew, or they know now, that an fpu is ofcourse not needed, for everyday use.

please stop posting here if you aren't interested in everything else about the fpu, than that it is not a vital part of the system.

[kidkoala]

@amigamenace

hehe, that whole post wasn't targeted at you..

i just get a little irritated when people can't stick to the benefit of the topic when we've clearly gotten to the point in the thread (within the first 10 posts or something), where everybody (i thought) knew that an fpu is not a vital component, and then goes on and on saying over and over again that it isn't. i just can't understand why someone wants to keep on like that..