/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *                    2003 Colin Walters <walters@verbum.org>
 *
 * gstcpu.c: CPU detection and architecture-specific routines
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "gst_private.h"
#include <glib.h>


#include "gstcpu.h"
#include "gstinfo.h"

static GStaticMutex _cpu_mutex = G_STATIC_MUTEX_INIT;
static guint32 _gst_cpu_flags = 0;

#if defined(HAVE_CPU_I386) && defined(__GNUC__)
#define _gst_cpu_initialize_arch _gst_cpu_initialize_i386
gboolean _gst_cpu_initialize_i386 (gulong * flags, GString * featurelist);
#else
#define _gst_cpu_initialize_arch _gst_cpu_initialize_none
gboolean _gst_cpu_initialize_none (gulong * flags, GString * featurelist);
#endif


void
_gst_cpu_initialize (gboolean opt)
{
  GString *featurelist = g_string_new ("");
  gulong flags = 0;

  if (opt) {
    if (!_gst_cpu_initialize_arch (&flags, featurelist))
      g_string_append (featurelist, "NONE");
  } else
    g_string_append (featurelist, "(DISABLED)");

  GST_CAT_INFO (GST_CAT_GST_INIT, "CPU features: (%08lx) %s", flags,
      featurelist->str);
  g_string_free (featurelist, TRUE);
}

gboolean
_gst_cpu_initialize_none (gulong * flags, GString * featurelist)
{
  return FALSE;
}

#if defined(HAVE_CPU_I386) && defined(__GNUC__)
static void
gst_cpuid_i386 (int x, unsigned long *eax, unsigned long *ebx,
    unsigned long *ecx, unsigned long *edx)
{
  unsigned long regs[4];

  asm (
      /* GCC-3.2 (and possibly others) don't clobber ebx properly,
       * so we save/restore it directly. */
"  movl %%ebx, %%esi\n" "  cpuid\n" "  movl %%eax, %0\n" "  movl %%ebx, %1\n" "  movl %%ecx, %2\n" "  movl %%edx, %3\n" "  movl %%esi, %%ebx\n":"=o" (regs[0]), "=o" (regs[1]), "=o" (regs[2]),
      "=o" (regs
          [3])
:    "a" (x)
:    "ecx", "edx", "esi");

  *eax = regs[0];
  *ebx = regs[1];
  *ecx = regs[2];
  *edx = regs[3];
}

gboolean
_gst_cpu_initialize_i386 (gulong * flags, GString * featurelist)
{
  gboolean AMD;
  gulong eax = 0, ebx = 0, ecx = 0, edx = 0;
  gboolean res = FALSE;

  g_static_mutex_lock (&_cpu_mutex);
  gst_cpuid_i386 (0, &eax, &ebx, &ecx, &edx);

  AMD = (ebx == 0x68747541) && (ecx == 0x444d4163) && (edx == 0x69746e65);

  gst_cpuid_i386 (1, &eax, &ebx, &ecx, &edx);

  if (edx & (1 << 23)) {
    _gst_cpu_flags |= GST_CPU_FLAG_MMX;
    g_string_append (featurelist, "MMX ");

    if (edx & (1 << 25)) {
      _gst_cpu_flags |= GST_CPU_FLAG_SSE;
      _gst_cpu_flags |= GST_CPU_FLAG_MMXEXT;
      g_string_append (featurelist, "SSE ");
    }

    gst_cpuid_i386 (0x80000000, &eax, &ebx, &ecx, &edx);

    if (eax >= 0x80000001) {

      gst_cpuid_i386 (0x80000001, &eax, &ebx, &ecx, &edx);

      if (edx & (1 << 31)) {
        _gst_cpu_flags |= GST_CPU_FLAG_3DNOW;
        g_string_append (featurelist, "3DNOW ");
      }
      if (AMD && (edx & (1 << 22))) {
        _gst_cpu_flags |= GST_CPU_FLAG_MMXEXT;
        g_string_append (featurelist, "MMXEXT ");
      }
    }
  }
  *flags = eax;
  if (_gst_cpu_flags)
    res = TRUE;
  g_static_mutex_unlock (&_cpu_mutex);

  return res;
}
#endif

GstCPUFlags
gst_cpu_get_flags (void)
{
  GstCPUFlags res;

  g_static_mutex_lock (&_cpu_mutex);
  res = _gst_cpu_flags;
  g_static_mutex_unlock (&_cpu_mutex);

  return res;
}