Re: Curiousity: pragma No_Run_Time for Gnat

["M. A. Alves" <maa@liacc.up.pt>]

or... The Meanings of "Pure"

Sergey Koshcheyev wrote:
> I don't know exactly what you [Marin Condic] mean by "pure" x86 code.
> What you get from the compiler on x86 is a 32-bit executable in the
> platform-specific executable format (ELF on Linux, PE on Win32)

You man the _target_ platform? (If so then code not pure.)

> which isn't linked to GNAT libraries, though I think it may be linked
> dynamically to the C library. Linker switch -nostdlib can be used to
> overcome this and get a completely stand-alone executable (tested on
> Linux). Another linker switch can be used to link the C library in
> statically (also tested on Linux).

You mean _compiled_ on Linux or _executed_ on Linux? (If the latter then
code not pure.)

> GNAT doesn't insert any BIOS calls in the generated code when pragma
> No_Run_Time is used.

Good.

But note that for OS execution it would be acceptable to depend on the
BIOS (at least early on the startup process); after all the BIOS is there
and it is running before the OS.  *** But it is not acceptable at all for
execution to depend on another OS. ***

In fact, I have been thinking in terms of a MIOS (Minimal Input/Output
System) package providing access to the "minimal system" I have suggested
before (Ada_OS talk) as a starting target (floppy, keyboard, screen): MIOS
would probably be implemented with BIOS services: hence, in part, the
tribute in its name.

BTW, what is GRUB?  And where is GNORT?

Thanks,

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