Re: NetBSD without MMU ?
[email protected] (Matthias Pfaller)
| Newsgroups | gmane.os.netbsd.ports |
|---|---|
| Message-ID | <[email protected]> |
In article <Pine.WNT.4.43.0204120853350.1248-100000@todd>, [email protected] (Todd Vierling) writes: > However, you do have to do some really major evil and hack the compiler to > make all code PIC-and-then-some (ensuring base register relative addressing > for all data accesses). No you don't. minix/x86 used segmentation (just like v7 on the pdp11). minix/68k used "shadow memory". After a fork the processes data segment was copied to "shadow memory". When the process switched to running the shadow memory image was exchanged with the "live" image. This is pretty expensive, but as soon as you exec, there is no more need for shadowing. Regards, Matthias -- Matthias Pfaller Software Entwicklung marco Systemanalyse und Entwicklung GmbH Tel +49 8131 5161-41 Hans-Böckler-Str. 2, D 85221 Dachau Fax +49 8131 5161-66 http://www.marco.de/ Email [email protected]