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Re:x86 Emulators

Posted: Tue Sep 07, 2004 5:51 am
by Brendan
Hi,
srg wrote: BTW IMHO the PC is desperately missing a method to do ICE on a normal motherboard.
I'd prefer a very good emulator. Something that could emulate an 80386 or an 8 way opteron server running in 64 bit (and everything in-between) that isn't restricted by the amount of resources in the host machine, and does have a good debugger.

Bochs is the closest thing I've found so far, but it's lacking PAE, ACPI, MSRs, NUMA, hyper-threading and is restricted by host resources. Bochs debugger needs improvements for multi-CPU. The BIOS code could also be done so that the same BIOS image works for all setups. Each BIOS function could be accelerated by simulation rather than emulation too.

I'd love to write an emulator with my OS as host, but by the time my OS is done I wouldn't need one so much (and I'm not immortal so time is a factor)...


Cheers,

Brendan

Re:x86 Emulators

Posted: Tue Sep 07, 2004 7:23 am
by srg
Brendan wrote: Hi,
srg wrote: BTW IMHO the PC is desperately missing a method to do ICE on a normal motherboard.
I'd prefer a very good emulator. Something that could emulate an 80386 or an 8 way opteron server running in 64 bit (and everything in-between) that isn't restricted by the amount of resources in the host machine, and does have a good debugger.

Bochs is the closest thing I've found so far, but it's lacking PAE, ACPI, MSRs, NUMA, hyper-threading and is restricted by host resources. Bochs debugger needs improvements for multi-CPU. The BIOS code could also be done so that the same BIOS image works for all setups. Each BIOS function could be accelerated by simulation rather than emulation too.

I'd love to write an emulator with my OS as host, but by the time my OS is done I wouldn't need one so much (and I'm not immortal so time is a factor)...


Cheers,

Brendan
Surly it would be best to be able to do exactly with what you do with bochs, but will a real machine, stop it, read write memory and registers, real probe mode stuff. I saw it done with a PowerPC before and it was great. Really I mean take any PC, from a 386 to an 8-way 64-bit opteron system and use it like you use a bochs emulation.

srg

Re:x86 Emulators

Posted: Tue Sep 07, 2004 8:17 am
by Brendan
Hi,
srg wrote: Surly it would be best to be able to do exactly with what you do with bochs, but will a real machine, stop it, read write memory and registers, real probe mode stuff. I saw it done with a PowerPC before and it was great. Really I mean take any PC, from a 386 to an 8-way 64-bit opteron system and use it like you use a bochs emulation.
IMHO a great emulator would be much better as you can test all CPUs with any combination of hardware (even impossible combinations, like an 80386 with PCI).

If you had a device that allowed you to use a real CPU like you'd use Bochs then it'd be very unlikely that it'd work on all computers, and also unlikely that you'd have that many real computers to plug it into. It would still be extremely useful though :).


Cheers,

Brendan

Re:x86 Emulators

Posted: Wed Jan 19, 2005 8:16 pm
by gilles
Have you tried Emu486 from www.gerisoft.net ?
It is base on RDOS 486 cpu emulation and uses some of Bochs devices.It's aim is to permit os developper to debug their OS.

Re:x86 Emulators

Posted: Tue Jan 25, 2005 5:50 am
by Brendan
Hi,
gilles wrote: Have you tried Emu486 from www.gerisoft.net ?
It is base on RDOS 486 cpu emulation and uses some of Bochs devices.It's aim is to permit os developper to debug their OS.
For my OS it dies during the boot sector - it thought "WBINVD" was an invalid instruction.

It does look promising though.


Cheers,

Brendan