Sender:	nate AT cartsys DOT com
Message-ID:	<35BA6D01.3293CF2C@cartsys.com>
Date:	Sat, 25 Jul 1998 16:40:49 -0700
From:	Nate Eldredge <nate AT cartsys DOT com>
MIME-Version:	1.0
To:	Vladimir Ignatov <ignatov AT deol DOT ru>
CC:	djgpp AT delorie DOT com
Subject:	Re: _lrotl replacement
References:	<35b9deda DOT 40014807 AT news DOT deol DOT ru>

Vladimir Ignatov wrote:
> 
> Hello
> 
> I have some Visual C  C++ sources with  _lrotl  function (cyclic
> rotate left).  Seem it is MS extension to standart C library. Which
> replacement can i use with GCC 2.8.1 ?

Assuming it does something similar to what it did in Turbo C:

/* Non-portable version */

inline unsigned long _lrotl(unsigned long n, int c)
{
   asm("roll %b2, %0"
       : "=g" (n)
       : "0" (n), "ci" (c));
   return n;
}

/* More portable version */
/* For constant `c', GCC should optimize it into a single `roll'
instruction (!) */

#include <limits.h>
inline unsigned long _lrotl(unsigned long n, int c)
{
   return (n << c) | (n >> ((sizeof(unsigned long) * CHAR_BIT) - c));
}

HTH
-- 

Nate Eldredge
nate AT cartsys DOT com

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