www.pudn.com > twofish-reference-c.zip > PLATFORM.H

/*************************************************************************** 
	PLATFORM.H	-- Platform-specific defines for TWOFISH code 
 
	Submitters: 
		Bruce Schneier, Counterpane Systems 
		Doug Whiting,	Hi/fn 
		John Kelsey,	Counterpane Systems 
		Chris Hall,		Counterpane Systems 
		David Wagner,	UC Berkeley 
			 
	Code Author:		Doug Whiting,	Hi/fn 
		 
	Version  1.00		April 1998 
		 
	Copyright 1998, Hi/fn and Counterpane Systems.  All rights reserved. 
		 
	Notes: 
		*	Tab size is set to 4 characters in this file 
 
***************************************************************************/ 
 
/* use intrinsic rotate if possible */ 
#define	ROL(x,n) (((x) << ((n) & 0x1F)) | ((x) >> (32-((n) & 0x1F)))) 
#define	ROR(x,n) (((x) >> ((n) & 0x1F)) | ((x) << (32-((n) & 0x1F)))) 
 
#if (0) && defined(__BORLANDC__) && (__BORLANDC__ >= 0x462) 
#error "!!!This does not work for some reason!!!" 
#include						/* get prototype for _lrotl() , _lrotr() */ 
#pragma inline __lrotl__ 
#pragma inline __lrotr__ 
#undef	ROL								/* get rid of inefficient definitions */ 
#undef	ROR 
#define	ROL(x,n)	__lrotl__(x,n)		/* use compiler intrinsic rotations */ 
#define	ROR(x,n)	__lrotr__(x,n) 
#endif 
 
#ifdef _MSC_VER 
#include						/* get prototypes for rotation functions */ 
#undef	ROL 
#undef	ROR 
#pragma intrinsic(_lrotl,_lrotr)		/* use intrinsic compiler rotations */ 
#define	ROL(x,n)	_lrotl(x,n)			 
#define	ROR(x,n)	_lrotr(x,n) 
#endif 
 
#ifndef _M_IX86 
#ifdef	__BORLANDC__ 
#define	_M_IX86					300		/* make sure this is defined for Intel CPUs */ 
#endif 
#endif 
 
#ifdef _M_IX86 
#define		LittleEndian		1		/* e.g., 1 for Pentium, 0 for 68K */ 
#define		ALIGN32				0		/* need dword alignment? (no for Pentium) */ 
#else	/* non-Intel platforms */ 
#define		LittleEndian		0		/* (assume big endian */ 
#define		ALIGN32				1		/* (assume need alignment for non-Intel) */ 
#endif 
 
#if LittleEndian 
#define		Bswap(x)			(x)		/* NOP for little-endian machines */ 
#define		ADDR_XOR			0		/* NOP for little-endian machines */ 
#else 
#define		Bswap(x)			((ROR(x,8) & 0xFF00FF00) | (ROL(x,8) & 0x00FF00FF)) 
#define		ADDR_XOR			3		/* convert byte address in dword */ 
#endif 
 
/*	Macros for extracting bytes from dwords (correct for endianness) */ 
#define	_b(x,N)	(((BYTE *)&x)[((N) & 3) ^ ADDR_XOR]) /* pick bytes out of a dword */ 
 
#define		b0(x)			_b(x,0)		/* extract LSB of DWORD */ 
#define		b1(x)			_b(x,1) 
#define		b2(x)			_b(x,2) 
#define		b3(x)			_b(x,3)		/* extract MSB of DWORD */