[syslinux] Comboot Menu

ganapathy murali krishnan gmurali at cs.uchicago.edu
Fri Jan 23 10:44:58 PST 2004


I compile my code into a .obj file, the linker takes this file
adds some startup code and creates a .COM file. So what we need here is 
some simple assembly code which just jumps to the location of main!
and sets the origin at 100h.

All my googling only resulted in very high level answers or to 
commercial products. And I have not yet found the reference to ROMable 
applications in Watcom manual.

BTW, can gcc generate files in COM format. Then I will have to rewrite 
all the assembly code in a way GCC understands :-( which inturn will 
mean I have to learn the AT&T syntax...., and then hopefully gcc and ld 
together can do the job (generating a 16bit real mode application).

Now I am slowly starting to think that all the 1200+ lines of code is 
going to the proverbial bit bucket.:-(

- Murali

H. Peter Anvin wrote:
> ganapathy murali krishnan wrote:
> 
>>
>> INT 21h, Functions 4Ah 40h 30h and INT 21h with AX=3D01h.
>>
> 
> Memory management, write file(?!), get DOS version, open file; get DOS 
> version is already implemented but OW probably want to check for DOS 
> 2.0+ or later.
> 
> Not something likely to do in SYSLINUX.
> 
>> Is there a flag to Open Watcomm which bypasses its startup code or 
>> something like that?
>>
>> Or will implementing dummy versions of these in SYSLINUX help?
>>
>> Basically, I am searching for some way to compile my C program which 
>> uses only int 10h, int 16h and SYSLINUX compatible parts of 21h to a 
>> .COM file which runs under ISOLINUX and preferably under DOS also if I 
>> do not run the SYSLINUX specific interrupts (All my calls to SYSLINUX 
>> API is wrapped around a check to see if we are running DOS 0.0).
> 
> 
> There is a section in the OpenWatcom manual called "writing ROMmable 
> applications" or something like that.  It describes, at least at a high 
> level, what one can do in "embedded" applications.
> 
> I don't know how helpful it is in how to modify the startup code, though.
> 
>     -hpa
> 






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