get_put.h

MINIX系统源码

/*
  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
  See the copyright notice in the ACK home directory, in the file "Copyright".
*/

/* $Header: get_put.h,v 1.3 89/10/25 17:15:01 ceriel Exp $ */

#include <byte_order.h>

#if CHAR_UNSIGNED
#define Xchar(ch)	(ch)
#else
#define Xchar(ch)	((ch) & 0377)
#endif

#define BYTES_REVERSED (MSB_AT_LOW_ADDRESS != FL_MSB_AT_LOW_ADDRESS)
#define WORDS_REVERSED (MSW_AT_LOW_ADDRESS != FL_MSW_AT_LOW_ADDRESS)
#define LONGS_REVERSED (FL_MSL_AT_LOW_ADDRESS)

#if BYTES_REVERSED
#define uget2(c)	(Xchar((c)[1]) | ((unsigned) Xchar((c)[0]) << 8))
#define Xput2(i, c)	(((c)[1] = (i)), ((c)[0] = (i) >> 8))
#define put2(i, c)	{ register int j = (i); Xput2(j, c); }
#else
#define uget2(c)	(* ((unsigned short *) (c)))
#define Xput2(i, c)	(* ((short *) (c)) = (i))
#define put2(i, c)	Xput2(i, c)
#endif

#define get2(c)		((short) uget2(c))

#if WORDS_REVERSED || BYTES_REVERSED
#define get4(c)		(uget2((c)+2) | ((long) uget2(c) << 16))
#define put4(l, c)	{ register long x=(l); \
			  Xput2((int)x,(c)+2); \
			  Xput2((int)(x>>16),(c)); \
			}
#else
#define get4(c)		(* ((long *) (c)))
#define put4(l, c)	(* ((long *) (c)) = (l))
#endif