Port-amiga archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: M68k backend has landed in LLVM - NetBSD support



Switching to 8KB pages is extremely simple and provides up to 960MB of virtual address space instead of 224MB; you change PGSHIFT from 12 to 13 and do a full rebuild. Here's the diff for hp300:

We've already done that for Amiga and (in current) mac68k. I suppose what's next would be to update MAXTSIZ, DFLDSIZ, MAXDSIZ and friends...

Bitsavers has all of the Motorola manuals online, in <http://www.bitsavers.org/components/motorola/68000/>. You'll want the 68851, 68030, 68040, and 68060 manuals.

I have several of these (M68030, M68060 books), and they're great references, but they really don't help with understanding the NetBSD pmap. I'm learning, but it's a slow process.

Probably the simplest possible change beyond switching to 8KB pages would be to increase the size of the root. Even if it's only increased statically (say based on a kernel config parameter -- you aren't going to make use of 4GB of virtual address space on an 8MB system) it doesn't take much to enable vastly more VM.

Increase the size of the root? I don't follow... Would love to hear more, though :)

John


Home | Main Index | Thread Index | Old Index