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julius |
/* stuff needed for libgcc on win32.
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*
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* Copyright (C) 1996, 1998, 2001, 2003 Free Software Foundation, Inc.
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* Written By Steve Chamberlain
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*
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* This file is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* In addition to the permissions in the GNU General Public License, the
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* Free Software Foundation gives you unlimited permission to link the
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* compiled version of this file with other programs, and to distribute
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* those programs without any restriction coming from the use of this
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* file. (The General Public License restrictions do apply in other
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* respects; for example, they cover modification of the file, and
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* distribution when not linked into another program.)
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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* As a special exception, if you link this library with files
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* compiled with GCC to produce an executable, this does not cause
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* the resulting executable to be covered by the GNU General Public License.
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* This exception does not however invalidate any other reasons why
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* the executable file might be covered by the GNU General Public License.
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*/
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#ifdef L_chkstk
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/* Function prologue calls _alloca to probe the stack when allocating more
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than CHECK_STACK_LIMIT bytes in one go. Touching the stack at 4K
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increments is necessary to ensure that the guard pages used
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by the OS virtual memory manger are allocated in correct sequence. */
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.global ___chkstk
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.global __alloca
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___chkstk:
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__alloca:
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pushl %ecx /* save temp */
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movl %esp,%ecx /* get sp */
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addl $0x8,%ecx /* and point to return addr */
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probe: cmpl $0x1000,%eax /* > 4k ?*/
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jb done
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subl $0x1000,%ecx /* yes, move pointer down 4k*/
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orl $0x0,(%ecx) /* probe there */
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subl $0x1000,%eax /* decrement count */
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jmp probe /* and do it again */
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done: subl %eax,%ecx
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orl $0x0,(%ecx) /* less that 4k, just peek here */
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movl %esp,%eax
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movl %ecx,%esp /* decrement stack */
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movl (%eax),%ecx /* recover saved temp */
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movl 4(%eax),%eax /* get return address */
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jmp *%eax
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#endif
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