Page 2 of 3
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Fri Jan 16, 2009 5:21 pm
by Troy Martin
I'll consider doing an 86/88 branch of TBOS, but don't expect it to be constantly updated to every main branch version. The hardest thing will be emulating the pusha/popa in the boot sector.
EDIT: Have to write a macro for each of the "jxx near" instructions and for pusha/popa. Rolling and shifting must be done through cl for rolls/shifts greater than 1 place.
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 12:57 pm
by jal
Troy Martin wrote:EDIT: Have to write a macro for each of the "jxx near" instructions and for pusha/popa. Rolling and shifting must be done through cl for rolls/shifts greater than 1 place.
Yeah, it got some limitations, though it' still my favourite old CPU :).
JAL
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 1:03 pm
by Troy Martin
Correction on my part: The hardest part will be finding and implementing a boot sector for reading the FAT from a 360 or 720 KB floppy.
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 1:07 pm
by jal
Troy Martin wrote:Correction on my part: The hardest part will be finding and implementing a boot sector for reading the FAT from a 360 or 720 KB floppy.
What's difficult about it? I've always assumed a boot sector looks the same on any format, but I guess I'm wrong...
JAL
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 1:12 pm
by jal
Some random links I googled which mention 360KB floppies:
http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html
http://wiki.fdos.org/Blog/Bernd
The second one has a bootable 360KB floppy image.
JAL
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 1:14 pm
by Troy Martin
Kewl, thanks. Expect a bootable TBOS 360 KB image within an hour
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 1:18 pm
by jal
Troy Martin wrote:Kewl, thanks. Expect a bootable TBOS 360 KB image within an hour :)
Hehe, cool, although I don't think I can test it this week on my real box :).
JAL
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 1:28 pm
by Troy Martin
I just need to figure out where the hell the loaded kernel is loaded to by the boot sector...
EDIT: After changing the segment to load to, I've come across some unknown jump to an invalid opcode (unhandled since the 8086 didn't have an invalid opcode vector) that the bochs debugger can't help me with. Sh!t.
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 4:49 pm
by Love4Boobies
There's bound to be some emulators/documentation on opcodes out there, I'm just too lazy to Google...
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 5:27 pm
by paxcoder
Ok, people: Who cares about 80186? I mean really. Noone has it.
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sat Jan 17, 2009 5:50 pm
by Troy Martin
What's your point? It's fun to develop for. Doing things like this is what OS development is all about!
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Mon Jan 19, 2009 6:25 am
by jal
paxcoder wrote:Ok, people: Who cares about 80186? I mean really. Noone has it.
I have it. Well, I have an 8088, that's why I asked TroyM to down-port it. It's cool having old hardware run new things. Check e.g.
SymbOS running on Z80 CPUs.
JAL
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sun Apr 12, 2009 7:22 am
by jal
Ok, just look at this beauty I just saved from my company's trash bin :)
JAL
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sun Apr 12, 2009 9:03 am
by Combuster
Wow, that they still had that stuff
Re: Contemplating the 80186 (Was: Open questions in OS design)
Posted: Sun Apr 12, 2009 9:46 am
by Troy Martin
Holy sh!t! Gimme gimme gimme
