/* ssw3i3.c: WIN32/INTEL STACK SCANNING
 *
 * $Id: //info.ravenbrook.com/project/mps/version/1.104/code/ssw3i3.c#1 $
 * Copyright (c) 2001 Ravenbrook Limited.  See end of file for license.
 *
 *  This scans the stack and fixes the registers which may contain
 *  roots.  See <design/thread-manager/>.
 *
 *  The registers edi, esi, ebx are the registers defined to be preserved
 *  across function calls and therefore may contain roots.
 *  These are pushed on the stack for scanning.
 *
 * ASSUMPTIONS
 *
 * .align: The stack pointer is assumed to be aligned on a word
 * boundary.
 */


#include "mpm.h"

SRCID(ssw3i3, "$Id: //info.ravenbrook.com/project/mps/version/1.104/code/ssw3i3.c#1 $");


Res StackScan(ScanState ss, Addr *stackBot)
{
  Addr *stackTop;
  Res res;

  __asm {
    push edi           /* these registers are the save registers  */
    push esi           /* and so may contain roots.  They are pushed */
    push ebx           /* for scanning */
    mov stackTop, esp  /* stack pointer */
  }

  AVER(AddrIsAligned((Addr)stackTop, sizeof(Addr)));  /* .align */
  res = TraceScanArea(ss, stackTop, stackBot);

  __asm {
    add esp, 0xc       /* pop 3 registers to restore the stack pointer */
  }

  return res;
}


/* C. COPYRIGHT AND LICENSE
 *
 * Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
 * All rights reserved.  This is an open source license.  Contact
 * Ravenbrook for commercial licensing options.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * 3. Redistributions in any form must be accompanied by information on how
 * to obtain complete source code for this software and any accompanying
 * software that uses this software.  The source code must either be
 * included in the distribution or be available for no more than the cost
 * of distribution plus a nominal fee, and must be freely redistributable
 * under reasonable conditions.  For an executable file, complete source
 * code means the source code for all modules it contains. It does not
 * include source code for modules or files that typically accompany the
 * major components of the operating system on which the executable file
 * runs.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
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