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From: krey@i30fs1.ira.uka.de (Andreas Krey)
Newsgroups: comp.lang.c
Subject: Re: Dereferencing Typecast Integer Literals
Message-ID: <91.035.15:59:53@ira.uka.de>
Date: 4 Feb 91 15:59:53 GMT
References: <22700@netcom.UUCP>
Sender: news@ira.uka.de (USENET News System)
Reply-To: krey@i30fs1.ira.uka.de (Andreas Krey)
Organization: University of Karlsruhe, FRG
Lines: 37

In article <22700@netcom.UUCP>, avery@netcom.UUCP (Avery Colter) writes:
> I would like to know something.
> 
> In BASIC (waiting for the groans to subside), there were the POKE, PEEK,
> and CALL commands, which respectively store a value in a location, read
> the present value of a location, or start executing a machine language
> function starting at the location.
> 

In C you may even define macros to make it more readable,
but it IS system dependent...
All macros cast the integer address to an appropriate pointer type
and then dereference it to get the lvalue/function.

#define LOC(x) (*((unsigned char*)(x)))
#define CALL(x) (((void (*)())(x))())

*(void (*()))0xFC58()

'BASIC'   <=>  'C'
a=PEEK(b) <=>  a=LOC(b);
POKE(b,c) <=>  LOC(b)=c;
CALL(x)   <=>  CALL(x);

If you want Parameters for Call:

#define FUNC(x) ((void (*)())(x))

CALL(f,a,b) <=> FUNC(x)(a,b);

(No Warranty for BASIC Syntax.)

Andy

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