small c program

[Bill Cunningham]

Can a small C program it put at int 19 and look at 0x7c00? This may or
may not be considered a C question I guess. Or is C too small to reside in
MBR?

Bill

[Richard Heathfield]

Bill Cunningham said:

Can a small C program it put at int 19 and look at 0x7c00?

This seems to be a question about a particular platform. I suggest you ask
your question in a newsgroup that deals specifically with programming for
that platform.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

[Malcolm]

"Bill Cunningham" <no****@nspam.com> wrote

Can a small C program it put at int 19 and look at 0x7c00? This may or
may not be considered a C question I guess. Or is C too small to reside in
MBR?

Most C compilers will allow you to set a pointer to an absolute address.
However this is of course completely non-portable, and it might not produce
the results you expect, depending on the system.

[Richard Heathfield]

Malcolm said:

"Bill Cunningham" <no****@nspam.com> wrote

Can a small C program it put at int 19 and look at 0x7c00? This may or
may not be considered a C question I guess. Or is C too small to reside
in MBR?

Most C compilers will allow you to set a pointer to an absolute address.
However this is of course completely non-portable, and it might not
produce the results you expect, depending on the system.

Yes, you'll generally be disappointed by the results if you're using a
protected-mode OS. Note, also, that to do this you will require a cast.
(That in itself is often a sign that you're doing something a bit worrisome
- but if you have to hack the hardware under a real-mode OS, it's certainly
a handy port in a storm.)

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

[Brytison]

C-compiler is dependce the OS, C program can't look 0x7c00 under the
protected-mode OS. use real-mode you will get it.

"Bill Cunningham" <no****@nspam.com> дÈëÏûÏ¢ÐÂÎÅ
:Aqpjf.163$fY3.150@trnddc01...

Can a small C program it put at int 19 and look at 0x7c00? This may or
may not be considered a C question I guess. Or is C too small to reside in
MBR?

Bill

[Mark McIntyre]

On Wed, 30 Nov 2005 23:49:42 +0000 (UTC), in comp.lang.c , Richard
Heathfield <in*****@invalid.invalid> wrote:

Malcolm said:

"Bill Cunningham" <no****@nspam.com> wrote

Can a small C program it put at int 19 and look at 0x7c00? This may or
may not be considered a C question I guess. Or is C too small to reside
in MBR?

Most C compilers will allow you to set a pointer to an absolute address.
However this is of course completely non-portable, and it might not
produce the results you expect, depending on the system.

Yes, you'll generally be disappointed by the results if you're using a
protected-mode OS.

Depends. Some people find dialog boxes advising you about illegal
memory access etc quite exciting....

--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt>

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