Need explanation of the CPU and FPU technology on turbo boards

[Piru]

@Vulture

Which one of those listed apps require FPU to function at all?

[AmiDude]

AmigaMance wrote:

That's right! And just to add a few more to this insightful and valid thread, the dir, cd and list comands of the AmigaDos requires a working FPU AND MMU! Without them, they just crash.

That's complete nonsence! My standard A600 (wich most Amiga folks know they have no FPU or MMU) don't require
a FPU or MMU to run the Dir, Cd, and List commands.
These commands run just fine without them.

[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

[AmiDude]

If it's a April 1 joke...I don't see the fun of it...
 :crazy:

[AmigaMance]

If it's a April 1 joke...I don't see the fun of it...

 Then try to see that i was making a point. The dir command is using the FPU as much as other apps mentioned here, earlier. :-)

[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

[AmiDude]

Then try to see that i was making a point. The dir command is using the FPU as much as other apps mentioned here, earlier.

Lol. One can count the apps that are using the FPU on the fingers of one hand...;-)

:lol:  

[kidkoala]

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

[AmiDude]

No need for that...It's a April 1 joke...
 :lol:

[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 frome one and 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. Notable exceptions are quake and warp3d enabled applications.

[Karlos]

Hyperspeed wrote:
One question springs to mind here... are the sadistic, aggresive people that program Quake actually mathematicians?

I'd imagine that the engine programmers have a reasonable grasp of vector arithmetic, linear algebra, kinematics etc ;-)

Just projecting and rasterizing polygons on screen (unless you are simply using something like glut) requires a good understanding of vectors and matrices.

[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.?

[DonnyEMU]

I would just tell you the following, back in the 80s I did everything I could to speed up my amiga 1000, including adding a 16 mhz 68000 processor with a 68881 math FPU.. I had to have specially designed math libraries to take advantage of this. However both the 16 mhz update and the FPU libraries weren't much help because:

a) not too many programs including cad supported the FPU without having it attached to the 60020 or inbuilt in the 68030. Those programs that did really didn't show any noticeable increase in speed. Mostly due to the speed of the other chips on the motherboard and how communication between those worked.

We generally came to the conclusion that this kind of upgrade was a complete waste of time, unless you like the tech and tinkering inside your box..

This whole thing about putting an FPU there for the minimal increase you get without being coupled with a 32 bit cpu and memory is pretty much a complete waste of time for the average user.

It's amazing to me to see these posts for something I tried 20 some years ago because I couldn't afford a faster CPU and I was trying to get every ounce of performance I could.

Still it's fun to toy with this stuff..

[Karlos]

kidkoala wrote:

@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.?

Generally not. Fixed point arithmetic (which is actually just integer in reality) is often used for 3D, simply because it has traditionally been too slow to use proper floating point. Even with an FPU, you can often write integer versions of polygon rendering code that, whilst less "accurate" than the floating point ones are much faster.

However, later demos written for 68060 probably do use the FPU for this. The 68060's FPU can typically do floating point multiplication faster than the IU can do integer multiplication.

[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.

[AmiDude]

The whole point about FPU's, without all the annoyance,
is that any Amiga with average use has no need for an
FPU whatsoever...