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From: roy@phri.UUCP
Newsgroups: net.lang.c
Subject: Re: Compiler Specific Operators
Message-ID: <2386@phri.UUCP>
Date: Sat, 12-Jul-86 14:36:11 EDT
Article-I.D.: phri.2386
Posted: Sat Jul 12 14:36:11 1986
Date-Received: Sun, 13-Jul-86 07:02:44 EDT
References: <1825@uw-beaver>
Reply-To: roy@phri.UUCP (Roy Smith)
Organization: Public Health Research Inst. (NY, NY)
Lines: 24
Summary: Isn't asm() what you're looking for?

In article <1825@uw-beaver> golde@uw-beaver.UUCP (Helmut Golde) writes:

> What do people think about allowing compilers to have their own
> compiler/machine specific operators, in a standardized format. [...]
> a $rol$= 5;	/* rotate a left 5 bits */

	If you want to do that sort of stuff (gross, but admitedly sometimes
worth the big efficiency win), what's wrong with the following?

# ifdef MY_FAVORITE_CPU
asm ("rol a, #5");	/* Use nifty built-in rotate left instruction */
# elseif
a = rol_func (a);	/* Don't have that instruction? do it in software */
# endif

	If you wanted to be cynical, you could always claim that we already
do have exactly what you are talking about :-)

	a <<= 5;	/* use nifty pdp-11 shift-left instruction */
	b = *--p;	/* use nifty pdp-11 auto-decrement mode */
-- 
Roy Smith, {allegra,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016