Determining Extended memory size in C program

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2 total messages Started by Roggie Boone Fri, 09 Oct 1992 20:49

#1071

Author: Roggie Boone
Date: Fri, 09 Oct 1992 20:49

36 lines
1715 bytes

I am trying to include code in my C program that will report the
amount of memory on a computer (Conventional, EMS, Extended).
I can use the Turbo C built-in function biosmemory() to get 
conventional memory.  I am having trouble with extended
memory.  I am trying to use BIOS INT 15 Function 88 for this.

The relevant subsection of my code is as follows:

	union REGS regs;

	basemem = biosmemory();    // reports 640K 

	_AH = 0x88;
	int86(0x15, &regs, &regs);
	cout << "Extended memory: " << _AX << endl;

My system has 7168K extended memory.  However, when I run the
code above it prints out "Extended memory: 34368".  According to
the documention I have, _AX should contain the number of K of
extended memory as reported by POST.  Thus I would expect, 
to see "7168" in AX.  Am I missing some conversion or something in 
there?

Thanks in advance for your help.

R. Boone
boone@athena.cs.uga.edu




-- 
Roggie Boone
Computer Support Staff                    Internet:  boone@athena.cs.uga.edu     
Dept. of Ag and Applied Economics         Internet:  roggie@aisun1.cs.uga.edu
University of Georgia                     Phone:  (706) 542-2482

Re: Determining Extended memory size in C program

#1072

Author: Ken Ballou
Date: Sat, 10 Oct 1992 01:06

12 lines
924 bytes

I think you might have better luck with:

	cout << "Extended memory: " << regs.x.ax << endl;

Using _AX instead of regs.x.ax means you write whatever is in register AX
after you evaluate cout << "Extended memory: " (in fact, that should be the
address of cout).

					- Ken
--
Kenneth R. Ballou			ballou@vmsdev.enet.dec.com
Digital Equipment Corporation		...!decwrl!vmsdev.enet!ballou

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