endian.c

来自「一个很有名的硬件模拟器。可以模拟CPU」· C语言 代码 · 共 109 行

/* endian.c - host endian probes */

/* SimpleScalar(TM) Tool Suite
 * Copyright (C) 1994-2003 by Todd M. Austin, Ph.D. and SimpleScalar, LLC.
 * All Rights Reserved. 
 * 
 * THIS IS A LEGAL DOCUMENT, BY USING SIMPLESCALAR,
 * YOU ARE AGREEING TO THESE TERMS AND CONDITIONS.
 * 
 * No portion of this work may be used by any commercial entity, or for any
 * commercial purpose, without the prior, written permission of SimpleScalar,
 * LLC ([e-mail]). Nonprofit and noncommercial use is permitted
 * as described below.
 * 
 * 1. SimpleScalar is provided AS IS, with no warranty of any kind, express
 * or implied. The user of the program accepts full responsibility for the
 * application of the program and the use of any results.
 * 
 * 2. Nonprofit and noncommercial use is encouraged. SimpleScalar may be
 * downloaded, compiled, executed, copied, and modified solely for nonprofit,
 * educational, noncommercial research, and noncommercial scholarship
 * purposes provided that this notice in its entirety accompanies all copies.
 * Copies of the modified software can be delivered to persons who use it
 * solely for nonprofit, educational, noncommercial research, and
 * noncommercial scholarship purposes provided that this notice in its
 * entirety accompanies all copies.
 * 
 * 3. ALL COMMERCIAL USE, AND ALL USE BY FOR PROFIT ENTITIES, IS EXPRESSLY
 * PROHIBITED WITHOUT A LICENSE FROM SIMPLESCALAR, LLC ([e-mail]).
 * 
 * 4. No nonprofit user may place any restrictions on the use of this software,
 * including as modified by the user, by any other authorized user.
 * 
 * 5. Noncommercial and nonprofit users may distribute copies of SimpleScalar
 * in compiled or executable form as set forth in Section 2, provided that
 * either: (A) it is accompanied by the corresponding machine-readable source
 * code, or (B) it is accompanied by a written offer, with no time limit, to
 * give anyone a machine-readable copy of the corresponding source code in
 * return for reimbursement of the cost of distribution. This written offer
 * must permit verbatim duplication by anyone, or (C) it is distributed by
 * someone who received only the executable form, and is accompanied by a
 * copy of the written offer of source code.
 * 
 * 6. SimpleScalar was developed by Todd M. Austin, Ph.D. The tool suite is
 * currently maintained by SimpleScalar LLC ([e-mail]). US Mail:
 * 2395 Timbercrest Court, Ann Arbor, MI 48105.
 * 
 * Copyright (C) 1994-2003 by Todd M. Austin, Ph.D. and SimpleScalar, LLC.
 */


#include "endian.h"
#ifndef HOST_ONLY
#include "loader.h"
#endif

/* probe host (simulator) byte endian format */
enum endian_t
endian_host_byte_order(void)
{
  int i = 1, *p;

  p = &i;
  if (*((char *)p) == 1)
    return endian_little;
  else if (*((char *)p) == 0)
    return endian_big;
  else
    return endian_unknown;
}

/* probe host (simulator) double word endian format */
enum endian_t
endian_host_word_order(void)
{
  int *p;
  double x = 1.0;

  /* NOTE: this check assumes IEEE floating point format */
  p = (int *)&x;
  if (*p == 0)
    return endian_little;
  else if (*p == 0x3ff00000)
    return endian_big;
  else
    return endian_unknown;
}

#ifndef HOST_ONLY

/* probe target (simulated program) byte endian format, only
   valid after program has been loaded */
enum endian_t
endian_target_byte_order(void)
{
  return ld_target_big_endian ? endian_big : endian_little;
}

/* probe target (simulated program) double word endian format,
   only valid after program has been loaded */
enum endian_t
endian_target_word_order(void)
{
  /* same as byte sex for SimpleScalar target */
  return endian_target_byte_order();
}

#endif /* !HOST_ONLY */