William Jhun wrote: > Hi Phil :o), > > The only problem with pure emulation is writing a good emulator for an > MMU. I wrote a SPARC V8 instruction set emulator a year ago and stopped > around the time I had to face the fact that a direct virtual->physical > mapping would no longer be of any use. (also the semester started again > :o). Not that it's not possible, but it's difficult and would require a > mapping with every memory access (being very slow). However, a little > creative help from the kernel and some creative mmap()ing might do the job > (you can request a specific linear address with mmap()). If anyone knows > some good methods for doing this, please inform! (and I might finish that > emulator :o) > > William > :) yep, you are right - the r3000 core in the mame sources I am perusing do not implement an mmu (the playstation and williams standups use "a custom r3000a by LSI Logic" - see src/cpu/mips/mips.c - no cache mechanism either). Poking around the mame sources (I've got xmame b13 r1 - ancient really, from sometime late 1999 I think), it appears that the z180 cpu is the only core that has some kind of mmu emulation. The z8k & m68k also have mmu instructions, but those were not emulated in this version of mame... I haven't checked more recent versions, but I think recent mess (uses same cpu cores as mame) supports early macs, so there may be an implementation example there?.. Phil > > On Wed, 25 Jul 2001, Phil Hopely wrote: > > > > > I do not know if you have examined any of the current open source emulation > > projects that exist, but I believe > > you might be interested to examine www.mame.net or mess.emuverse.com? > > > > They have a cpu core for mips emulation, I believe it may only be r3000 > > though?.. > > > > Also, there exist numerous open-source playstation emulators, which I believe > > are r3000 based too... > > > > The mame & mess projects are matured open-source projects that have been ported > > across the universe, they're really pretty cool, this work would be a likely fit > > with the mess project. > > > > If you implement by way of pure emulation, you'd not need to change the kernel > > at all? > > > > Phil > > > > "John D. Davis" wrote: > > > > > I am modifying the linux kernel to be able to be run by a simulator. I > > > need to modify the console driver and interrupt handler. I have been > > > going through the various files, console.*, tty.* and the serial files to > > > see how to interface to the console. I have also read some kernel korner > > > articles, but they seem a little out of date. Is there any other > > > recommended documentation on the console driver and how it works on an > > > indy? I am trying to sort out the low-level interfaces from the > > > higher-level ones. I just need to change the low-level interface from > > > using the hardware to using the simulator interface. > > > > > > thanks, > > > john > > > > > > -- > > > To UNSUBSCRIBE, email to debian-mips-request@lists.debian.org > > > with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org > >
