Posted: Wed Jun 02, 2004 2:05 pm Post subject: CPU and FPU plug-ins available for PocketDOS (v1.09.0+)
Q: What are CPU and FPU plug-ins?
A: PocketDOS emulates an i80186 CPU. Most DOS applications are targeted at an i8086 processor and so can run under PocketDOS. There are however many recent DOS applications which require an i80386 or later processor. The latest version of PocketDOS is able to load 3rd party CPU emulators to emulate later processors. There are also many DOS applications available that are able to make use of a maths chip to speed up calculations. Without a maths chip, the application must perform it's calculations in software. When running under an emulator, this can provide poor performance. The latest version of PocketDOS is also able to load 3rd party FPU (maths chip) emulators to speed up applications that are able to take advantage of a maths chip.
Q: Which CPU and FPU plug-ins are available?
BOCHS - This CPU emulator is based on the x86 CPU emulator from Bochs (by Kevin Lawton).
It has been compiled to emulate an i80486 processor with a built-in FPU. This release is based on Bochs 2.11: http://www.pocketdos.com/Misc/PDOS_BOCHS_CPU.zip
WMFPUEMU - This FPU emulator is based on the FPU emulator from Bochs (by Kevin Lawton),
which in itself is based on the wmemu FPU emulator for DJGPP (by William
Metzenthen), which in turn, is based upon wm-FPU-emu (the FPU emulator of the
Linux operating system). This release is based on Bochs 2.11:
DOSBOX - This CPU emulator is based on the 80486 CPU emulator from DOSBox (by The DOSBox
Team). It has been compiled to emulate an i80486 processor with no built-in FPU. This release is based on DOSBox 0.61: http://www.pocketdos.com/Misc/PDOS_DOSBOX_CPU.zip
All of the above emulators are provided "as is" with full source code.
The most useful of these currently is the FPU emulator plug-in, as it provides a 10x speed improvement in floating point operations for applications which are able to use a floating point processor.
The Bochs CPU emulator plug-in is mostly useful for testing the DOSBox CPU emulator plug-in. The DOSBox plug-in is not complete yet, as it is not able to run some software which both the Bochs plug-in and the actual DOSBox application are able to run.
The resultant "computer" created by using these plug-ins is fairly non-standard (a i80486 on a cut-down XT motherboard), and so even though PocketDOS now has some AT BIOS functionality and A20 address line control, there are some memory managers and operating systems that are not able to run under PocketDOS.
These plug-ins, will no doubt be in constant development, and there are still 2 or 3 other interesting CPU emulators which could be ported to the plug-in model used by PocketDOS.
dune2 works well with the wmfpu plugin
i couldn't get pocketdos to run with the dosbox & bochs cpu plugins, the last thing the inialisation window says is couldn't initialize.. doesn't even try to start the image file of the rom
is there anyway to debug it? i got 26 mb of ram free on my xda2
Q: How do I set the amount of extended memory used by a CPU emulator?
A: PocketDOS uses the EMS (expanded) memory setting to determine how much extended memory to provide. Setting the EMS (expanded) memory to 4Mb will result in 5Mb of total memory when using a CPU emulator plug-in (1Mb + 4Mb extended).
Q: How can I tell if a CPU plug-in has loaded?
1) Set the amount of EMS (expanded) memory to a non-zero value, and restart PocketDOS. Type MEM from the DOS prompt. If PocketDOS has not tried to load a CPU plug-in, then MEM will list 1Mb conventional and 64Kb extended memory. If it lists extended memory, then it has at least tried to load the CPU plug-in.
2) Run a diagnostics utility like Microsoft MSD or Norton SI.
Joined: 19 May 2004 Posts: 18 Location: Paris France
Posted: Thu Jun 03, 2004 1:48 am Post subject:
Can you confirm that it is normal, that even if the dosbox plugin is loaded (extended memory detected), I've got an [Error 15] message, saying that there is no 386 processor, as soon as I want to launch a Dos4gw application ?
(most of the VGA games)
According to some info i found on this forum today, these plug-ins SLOW DOWN the emulator!? Conclusion: Without changing anything, it emulates something faster that i80486?? Just hope you wont let us too down with the Psion/Symbian version! So am I wrong or does the i80X86 mean same as X86, like i80386=386?
PocketDOS emulates an 80186 processor, which is a relatively simple processor to emulate in comparison to an 80486 processor. Given that the the added complexity of emulating a >80186 processor slows down the emulation by several orders of magnitude we decided not to develop >80186 emulation for PocketDOS (being that the current 80186 emulation has barely acceptable performance as it is). However there are several OpenSource PC emulators available and we have adapted the CPU emulation components of two of these emulators (Bochs & DOSBox) so that they can be used as plug-ins for PocketDOS. It is the added complexity (and possibly the design) of these emulators which results in them giving poorer performance than our own 80186 emulator.
Thank you for your interest. _________________ PocketDOS - Adds DOS compatibility to your Pocket Computer.
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