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From: platt@emory.uucp (Dan Platt)
Newsgroups: comp.sys.ibm.pc,comp.lang.c
Subject: Re: Looking for C functions to access PC memory
Message-ID: <2312@emory.uucp>
Date: Sat, 7-Nov-87 16:38:41 EST
Article-I.D.: emory.2312
Posted: Sat Nov  7 16:38:41 1987
Date-Received: Tue, 10-Nov-87 05:04:45 EST
References: <24261F3U@PSUVMB>
Reply-To: platt@emory.UUCP (Dan Platt)
Organization: Emory University
Lines: 39
Xref: mnetor comp.sys.ibm.pc:9892 comp.lang.c:5330

In article <24261F3U@PSUVMB> F3U@PSUVMB.BITNET writes:
>I am looking for some functions when called from a C program, will:
>      1)  read (peek) memory directly when supplied with
>          an address.  Returns with the value at specified address.
>  and
>      2)  write (poke) memory directly when supplied with an
>          address and a byte value.
>     
>I am using Microsoft C 4.0 on an AT&T 6300 PLUS.  Routines
>in C or Assembler OK.



The way I did it was to define a routine that loads a pointer with
a value pointed to by a segment/offset...
__________________________________________________________________

far char * mem_pt(seg,offst)  /* this may be coerced */
short seg,offst;
{
	union	{
		struct {
			short: ofst,sg;    /* these may be backwards */
		} vals;
		far char * ptr;
	} pointr;

	pointr.vals.sg= seg;
	pointr.vals.ofst=offst;

	return(pointr.ptr);
}

____________________________________________________________________

This was off the top of my head, and may be a little off on syntax, but
not by much.  Hope this is a help.

Dan