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Picnic



Joined: 05 May 2007
Posts: 1288
Location: behind the arc
Picnic
I'm doing for some months now 16-bit asm using Fasm. Love it.
How about 32 bit. What are the differences, what to read and where i must start? Why should i learn this stuff?
I'm interested in Dos programming.
please advice, thanks people.
Post 05 Sep 2007, 20:32
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f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
f0dder
First you need to decide what kind of 32bit stuff you want - do you want to be able to call DOS/BIOS functions? Easiest way to go is to use a DOS extender that takes care of the nasty nitty gritty stuff, google for HDPMI and/or WDOSX.

Why you should learn the stuff? *shrug*. 32bit is easier to work with than 16bit.
Post 06 Sep 2007, 10:20
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Picnic



Joined: 05 May 2007
Posts: 1288
Location: behind the arc
Picnic
Thanks for the reply f0dder.
I'm reading now about dos extenders, it's a start!
Post 06 Sep 2007, 16:39
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
A good starting point for you would be to code for DexOS its a 32bit pmode Dos.
You can call int like Dos or use the call-table.
Here a simple demo to write a hello world in realmode Dos is
Code:
; fasm example of writing 16-bit COM program       org     100h                    ; code starts at offset 100h  use16                           ; use 16-bit codedisplay_text = 9       mov     ah,display_text       mov     dx,hello      int     21h int     20hhello db 'Hello world!',24h    


To do the same in DexOS you do this:
Code:
use32org  0x400000 ; We are load to 4MBjmp  start  ; Jump to start of program.db   'DEX2' ; This is checked to make sure it a DexOS programstart:mov   esi,hello ; Points to our string.mov   ebx,9 ; Function numberint   41h ; int like Dos's int 21hret ; Return to CLIhello db 'Hello world!',0 ;Zero ended string    


The above is for the new ver of DexOS dew out this week.
Post 06 Sep 2007, 18:24
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DOS386



Joined: 08 Dec 2006
Posts: 1901
DOS386
> What are the differences

- Get rid of 64 and 640 KiB bugs Smile
- Need extender/DPMI host Neutral
- Most bugs get caught now Smile

> what to read

FAQ at the top.

> and where i must start

Hello world. One by Tomasz (USEDPMI), one by me (LE), one by Japheth (FASMHX).

> The above is for the new ver of DexOS dew out this week.

OK Neutral
Post 06 Sep 2007, 22:10
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Picnic



Joined: 05 May 2007
Posts: 1288
Location: behind the arc
Picnic
Dex hi,
I've been a few times at DexOS website, read some info about the OS, visited the forums (and found lots of code!). DexOS is very interesting.
Lack of free time keeps me away so far.

Thanks for the information NTOSKRNL_VXE.
Post 07 Sep 2007, 21:11
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