What requires an FPU?

[Heiroglyph]

I'm trying to find out what 68k applications require an FPU.

By that I mean, what will refuse to run without one?

I'm trying to find the most basic 68k CPU that pretty much all OS legal software would run on and that seems like the 68020 with no MMU or FPU.

Thanks!

[ChaosLord]

I'm trying to find out what 68k applications require an FPU.

Lightwave 3D, Imagine, Aladdin 4D, etc.
All 3D gfx apps.

Pagestream, Art Expression, WordWorth, FinalWriter etc.
All 2D Desktop Publishing apps.

Mp3 players, .ogg players, video players, anything that lossy compresses or decompresses audio or video.

Anything that handles postscript or truetype fonts.

A few games.

A few utils.

[itix]

Pagestream, Art Expression, WordWorth, FinalWriter etc.
All 2D Desktop Publishing apps.

Are you sure? I recall at least WW and FW run on unexpanded Amigas without an FPU.

[ChaosLord]

Are you sure? I recall at least WW and FW run on unexpanded Amigas without an FPU.

I only ever ran WW and FW on Amigas with FPUs so all I can really say is they really need an FPU, especially during printing, for smooth-scaling the scalable fonts.

[Piru]

Lightwave 3D, Imagine, Aladdin 4D, etc.
All 3D gfx apps.

Pagestream, Art Expression, WordWorth, FinalWriter etc.
All 2D Desktop Publishing apps.

Mp3 players, .ogg players, video players, anything that lossy compresses or decompresses audio or video.

Anything that handles postscript or truetype fonts.

I'm fairly sure that most of these do not require an FPU. Only some very specific apps have been compiled by using the FPU instructions directly.

they really need an FPU, especially during printing, for smooth-scaling the scalable fonts.

There's nothing in scalable fonts that'd require FPU.

[Heiroglyph]

Yes, just to clarify:

I don't care what can optionally take advantage of an FPU.

What won't run without one?

Thanks

[ChaosLord]

Yes, just to clarify:

I don't care what can optionally take advantage of an FPU.

What won't run without one?

Thanks

@Heiroglyph and Piru

Well nothing requires an FPU if u want to get technical.

You can just run an FPUpatch that emulates the missing FPU instructions.

I do not recommend doing this as they generate a TON of interrupts that mess up mouse movements and damage the multitasking, unless it is like OxyPatcher, which I have heard good things about but never actually used.

Most software (all software that I have peeked at the sourcecode to) that renders scalable fonts, does lots of heavy floating point math.  I have heard that the compugraphic fonts are coded to be 100% integer. (They have size limitations as a result).  But PostScript definitely does hardcore FP work.  So I assume TrueType does too.

As a practical matter, all good mp3 players use floating point.  You need the FPU for speed reasons.  No FPU = too slow to be useful.
There are integer mp3 sourcecodes available but they generate sloppy sound.  It says so right in the readme file.

[Karlos]

Warp3D requires an FPU.

[Daedalus]

Well, these are things that can use an FPU indeed, but I think most of those apps and tasks either detect that no FPU is present and use integer maths instead, or have separate non-FPU executables. MP3 players for example don't need an FPU, but if you use it it gives a more accurate result. If you use the FPU version of MPEGA.library however, it is actually slower than the integer version, so it's nothing to do with integer being "too slow to be useful."

[Piru]

As a practical matter, all good mp3 players use floating point. You need the FPU for speed reasons.  No FPU = too slow to be useful. There are integer mp3 sourcecodes available but they generate sloppy sound.  It says so right in the readme file.

Actually that is not the case. See: http://www.underbit.com/products/mad/

libmad is used in a replacement MPEGA.library for amiga, resulting in significantly faster decoding than when using FPU: http://aminet.net/package/util/libs/mpega_libmad

[psxphill]

Actually that is not the case. See: http://www.underbit.com/products/mad/
 
libmad is used in a replacement MPEGA.library for amiga, resulting in significantly faster decoding than when using FPU: http://aminet.net/package/util/libs/mpega_libmad

Yeah, I always used integer back in the day. The FPU accelerates floating point, but fixed point is faster. Plus fixed point is more accurate.
 
All floating point maths does is sacrifice accuracy for range for lazy coders. You never use floating point for financial calculations, because it's innaccuracy means you lose money.

[ChaosLord]

@Piru et al.
Kewl!   Thanx 4 da infos!  Finally someone made a good integer mp3 playback routine!!!  I was looking for one about 3 years ago and could not find one anywhere!

I mean the one I found was integer but it was claimed to not actually be any faster and it was definitely a lot more inaccurate.  It said its sole purpose was to run on devices that lacked an FPU therefore it was a success in that regard.

Sounds as if libmad is like PFS3 for mp3 playback

[TheGoose]

Hmm, usefulness on FPU is looking pretty low in this thread. FPU, you need to go get a job!

[Iggy]

This thread is encouraging. After looking at the mythical "FE133" chips used on one version of the Natami '060 board, I've decided to look at MC68EC060RC75 chips as a possible overclocking processor.
It appears that'060s without an MMU or FPU can overclock better.
I believe it might be possible to get to 100Mhz or better.

[SpeedGeek]

FPU version is more accurate but slower than integer version!
See the readme for mpega.library here:
http://fi.aminet.net/util/libs/mpega_library.readme
 
However, for apps which actually require Floating Point support hardware FPU is certainly faster than Floating Point emulation.