12 Nov
2005
12 Nov
'05
12:13 p.m.
On 11/9/05, Brantley Coile <brantley(a)coraid.com> wrote:
my suggestions are as follows (i assume you really
mean 8086 mode):
That wouldn't be a good match. I believe you want this:
* 16-bit
* protected mode
* no paging
* 8 or 16 segments
* 128 kB of the memory
* no FPU
using a floppy to boot is a great idea. i've
written several boot
straps to boot from the floppy that configure the serial port, and put
the processor in 32-bit mode. it's tight, but not too hard. you have
a great advantage in that you're going to stick to 16 bit so you can
use the bios. 512 bytes in that case is tons of space.
512 is easy until you try to handle more than one machine. :-(
next you'll need to write device drivers for the
screen/keyboard, the
clock, and the floppy. later you can write an ATA driver and get a
mbr and hard disk boot strap.
I think you need a 4 MB disk and a 10 MB disk. :-)
if you want to do a 32-bit version, then things are a
little
different. but this should give you the v6 in about as little
work as can be.
You might use a 32-bit CPU in 16-bit mode. Then you could use
a 32-bit limit on the FS or GS segment for easier physical memory
access from the kernel. (use an opcode prefix as needed)