Re: Configuring for bare hw ia32 PC's

["Luke A. Guest" <laguest at archeia dot com>]

On Sun, 2008-05-11 at 18:38 -0400, duane ellis wrote:

> A while back - (April) Jonathan Shapiro was asking about something like 
> this for his Cayotie (spelling?) Operating system

CoyotOS

> I whipped up a simple example for x86 and sent it to him, You might want 
> to take a look at this as starting point/example.

OK

> (0) My assumption is you load your kernel with something like uboot or grub, or
>     and that thing can load an "elf" file - because that is what this 
> generates.
> 

For PC it will be GRUB2, I intend to also get it going on other
architectures.

> Basically all you need to do is:
> 
> (1) figure out your desired memory map - and thus your linker script.
> 
> (2) Add appropriate startup code to set registers - establish the stack etc.
> 
>     Deal with other 'machine specific stuff'
> 
> (3) The attached example - has an example "fake_syscalls.c"
> 
>     These functions could make 'bios' calls.
>     That is your job, you need to write that.
> 
> ================
> Two things to note:
>     (A) This might be a starting point for you.
> And
>     (B) it might not, NEWLIB is more of an application standard C library.
>        Not really a "kernel standard c library"

Well, not strictly. It seems that NewLib is actually what I want, a libc
that can provide the basics, even dummy functions.

> It's a matter of personal preference.  I believe kernels should have a 
> stripped down or reduced standard c library  Apps - need the full 
> thing.   My reasoning centers around 'syscalls' and the problem of 
> kernel code calling functions like 'fopen()' etc.... And - the fact that 
> the kernel uses a single language, and does not require things like 
> "locale" - the APP does - but not the kernel.
> 
> If you look at the makefile - it builds GCC in 2 stages stage 1 - is 
> just a straight up C compiler, nothing else. No standard library. That 
> should be enough to build your kernel as I describe.

Not quite, I want to get a cross Ada compiler (GNAT) and runtime going
for this, therefore I need a libc, this includes (unfortunately the file
I/O).

Thanks,
Luke.