To: djgpp AT delorie DOT com
Subject: Re: A couple quick questions invloving GNU Pascal: Books, 
	Accessing memory and Ports
Message-ID: <19970106.200214.4975.5.chambersb@juno.com>
References: <5as7s9$8m AT acs1 DOT star DOT net>
From: chambersb AT juno DOT com (Benjamin D Chambers)
Date: Mon, 06 Jan 1997 22:56:42 EST


On Tue, 07 Jan 1997 01:06:21 GMT brin AT star DOT net (Brin) writes:
>Hello everyone,
>I realize this is a very stupid question and that it should be
>painfully obvious, but I cannot seem to find the answer.  Basically, I
>recently started programming in the DJGPP-GPC enviornment and have
>been able to do alot the of the basic stuff, I am very familiar with
>Turbo Pascal.  Unfortunentally, I am not familiar with the other
>languages that the compiler is based on (ansi, extended etc.) and an
>not familiar with protected mode.  I was wondering if there are any
>good books/docs etc on the subject.
>
>Also, I have been trying to find out about how to write, say a byte,
>directly to memory or to read a byte directly from memory.
>
>ie
>
>var 
>  P : ^void;
>
>begin
>  .
>  .
>  .
>  GetMem(P, The_Space_I_Need);
>  P := $A0000;                                      {Video Memory}
This is the problem.  P, a pointer to nothing (I usually used ^byte), is
pointing at the address $a0000.  In real mode, this is $a0000.  In
protected mode, this could be anywhere.  I know how to work around this
in C, but I haven't used GNU Pascal (only Borland), so I don't know the
work-around... sorry. :(
>  . 
>  .
>  .
>end.
>
>
>  Now how do I read the and write to the memory I have allocated.  In
>Turbo Pascal, i could use the mem[segment:offset] array, but that is
>not available in GNU Pascal...   
>
>  I also wish to be able to read and write to ports, of the material I
>have found, I know that the port[] array that was in Turbo Pascal is
>also no longer available.  What can I do in its place (ie writing to
>SB registers and to the Palette registers)
>
>Any help on any of the above problems would be of a huge help!
>
>Thanks in advance
>-Brin
>
>                           "I am therefore I think"
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