a heavily stripped down FreeBSD/i386 (brutally stripped down actually) to
attempt to get a stable base to start from. There is a lot missing still.
Worth noting:
- The kernel runs at 1GB in order to cheat with the pmap code. pmap uses
a variation of the PAE code in order to avoid having to worry about 4
levels of page tables yet.
- It boots in 64 bit "long mode" with a tiny trampoline embedded in the
i386 loader. This simplifies locore.s greatly.
- There are still quite a few fragments of i386-specific code that have
not been translated yet, and some that I cheated and wrote dumb C
versions of (bcopy etc).
- It has both int 0x80 for syscalls (but using registers for argument
passing, as is native on the amd64 ABI), and the 'syscall' instruction
for syscalls. int 0x80 preserves all registers, 'syscall' does not.
- I have tried to minimize looking at the NetBSD code, except in a couple
of places (eg: to find which register they use to replace the trashed
%rcx register in the syscall instruction). As a result, there is not a
lot of similarity. I did look at NetBSD a few times while debugging to
get some ideas about what I might have done wrong in my first attempt.
we are required to do if we let user processes use the extra 128 bit
registers etc.
This is the base part of the diff I got from:
http://www.issei.org/issei/FreeBSD/sse.html
I believe this is by: Mr. SUZUKI Issei <issei@issei.org>
SMP support apparently by: Takekazu KATO <kato@chino.it.okayama-u.ac.jp>
Test code by: NAKAMURA Kazushi <kaz@kobe1995.net>, see
http://kobe1995.net/~kaz/FreeBSD/SSE.en.html
I have fixed a couple of style(9) deviations. I have some followup
commits to fix a couple of non-style things.
the OS does FXSAVE/FXRESTOR instructions (fast FPU save/restore) during
context switching and also enables SIMD since this enables saving the
extra CPU context that isn't saved with normal FPU regs. The other
enables the SIMD instructions to use exception 16 (FPU) error reporting.
Note, this doesn't turn on SIMD, just defines the bits.
The code was originaly contributed by Kelly Yancey
<kbyanc@freedomnet.com> in PR i386/6269 and revised by Akio Morita
<amorita@meadow.scphys.kyoto-u.ac.jp> and me. Test was performed by
Akio Morita and Toshiomi Moriki <moriki@db.is.kyushu-u.ac.jp>.
- Fix stylistic bug in identcpu.c.
- Update copyright in initcpu.c
- Fix typo in LINT.
PR: 6269 and 6270
supports All Cyrix CPUs, IBM Blue Lightning CPU and NexGen (now AMD)
Nx586 CPU, and initialize special registers of Cyrix CPU and msr of
IBM Blue Lightning CPU.
If revision of Cyrix 6x86 CPU < 2.7, CPU cache is enabled in
write-through mode. This can be disabled by kernel configuration
options.
Reviewed by: Bruce Evans <bde@freebsd.org> and
Jordan K. Hubbard <jkh@freebsd.org>
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
negation whenever we access memory between 640k and 1M.
Original code from NetBSD 1.0-BETA. The exact origins are unclear but
Theo de Raadt, Charles, and Michael V. may have contributed to it.
Submitted by: pst
