What exactly do you want to run that requires a 286 machine with FPU?

Have you considered Bochs?

There's also the relatively obscure Soviet PC-XT emulator.

There was an FPU emulator (em87?) for 186+. Might work with Dosbox/PC-EM

@Jorpho I use them on some of my 286's to accelerate AutoSketch, Windows 3.1 and WinFract.
They're also nice for old raytracers. Of course, a 486 will also do the job. Can't think of an x87 accelerated, but 286-only software either.
Perhaps the OP is using a speed sensitive software with a 16bit extender ? Or an old OS like OS/2 1.x or Xenix ?

leileilol wrote:

There's also the relatively obscure Soviet PC-XT emulator.

Oh, that's the same author who made Script PC! I successfully ran Win 3.1 on that emulator in 286 mode.
However, VGA didn't work for me (missing BIOSes ?). I used CGA or Hercules instead.

keenerb wrote:

There was an FPU emulator (em87?) for 186+. Might work with Dosbox/PC-EM

Yup, I remember "EMUL87". It's in my collection, too. I got it with manual and floppy from a german ebay seller.
You can get a copy here. If you want the opposite - you want to "disable" an existing co-processor, look for an utility named "hide87".

leileilol wrote:

There's also the relatively obscure Soviet PC-XT emulator.

Thank you for the link

Jorpho wrote:

What exactly do you want to run that requires a 286 machine with FPU?

I'm just trying to learn Assm and the arhchitecture of old PC's and I want an emulator in my modern laptop behave exactly as my 286-20 real machine - to exchange files from it to emulator - to work on real hardware at home and in emulator, being on the road)

Jorpho wrote:

Have you considered Bochs?

ScoutPilot19 wrote:

Jorpho wrote:

What exactly do you want to run that requires a 286 machine with FPU?

I'm just trying to learn Assm and the arhchitecture of old PC's and I want an emulator in my modern laptop behave exactly as my 286-20 real machine - to exchange files from it to emulator - to work on real hardware at home and in emulator, being on the road)

Jorpho wrote:

Have you considered Bochs?

Ah okay, sounds cool! 😀
Btw, There were also tiny laptops with 80188 processors/µC (called "Palmtop PCs" by our ancestors).
I know, they aren't quite the same as real 286 machines (long-time 286 user here!) but from a real-mode point-of-view they are quite capable (asm..).

List of DOS-based palmtop computers
http://www.tankraider.com/DOSPALMTOP/list.html

Alternatively, if you want to go the emulation route, there's another solution for PalmOS/Win(CE) devices.
It features 8088-80286 emulation and also has an optional i80387 FPU emulator plug-in available for download.

Have a look at my post from this thread (beware, shameless self-advertisment here! 😁 ):
Re: Handheld PC's: What happened to them?

The only other emulators left I know of are MESS and MAME. Maybe some of them do emulate a PC/AT compatible model that's useful for you.
Other emulators like qemu or bochs are also worth a try. However. I don't know whether these are cycle-exact or not. 🙁

MAME is definitely worth a look. Not sure if it meets ScoutPilot19's needs, but definitely worth a look. 😀

We don't yet emulate 8087s or 80287s yet although there's at least one partially working machine that requires it so that's on the todo list.