Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!kaleb
From: kaleb@mars.jpl.nasa.gov (Kaleb Keithley)
Newsgroups: comp.sys.ibm.pc
Subject: Re: POKE, PEEK, FAR POINTER
Keywords: ON a AT with Microsoft C
Message-ID: <2886@jato.Jpl.Nasa.Gov>
Date: 20 Feb 90 23:46:13 GMT
References: <848@dukempd.phy.duke.edu> <8389@cg-atla.UUCP>
Sender: news@jato.Jpl.Nasa.Gov
Reply-To: kaleb@mars.UUCP (Kaleb Keithley)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 28

In article <8389@cg-atla.UUCP> fredex@cg-atla.UUCP (Fred Smith) writes:
>In article <848@dukempd.phy.duke.edu> fang@dukempd.phy.duke.edu (Fang Zhong) writes:
>>	Here is something I have tried and it did not work.
>>	unsigned far *addr;
>>	unsigned seg, offset, byte;
>
>>	addr = NULL;
>>	addr += seg*16 + offset;
>>	*addr = byte;
>MIcrosoft C has a pair of macros called FP_SEG and FP_OFF which are

>FP_SEG(addr) = (segment value);
>FP_OFF(addr) = (offset value);

Another way to set a far * is as follows
assuming, say you want to look at VGA screen memory at A000:0000

unsigned far *addr;

addr = (unsigned far *)A0000000;

I always thought the FP_SEG and FP_OFF macros were to get the segment/offset
components from some initialized far pointer.

Chewey, get us outta here!
                 
kaleb@mars.jpl.nasa.gov            Jet Propeller Labs
Kaleb Keithley