usr/src/lib/libc/i386/gen/alloca.s

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26         .file   "alloca.s"
  27
  28 #include "SYS.h"
  29
  30         ENTRY(__builtin_alloca)
  31         popl    %ecx                    / grab our return address
  32         movl    (%esp),%eax             / get argument
  33         addl    $3,%eax
  34         andl    $0xfffffffc,%eax        / round up to multiple of 4
  35         subl    %eax,%esp               / leave requested space on stack
  36         leal    4(%esp),%eax            / adjust, accounting for the "size" arg
  37         pushl   %ecx                    / put back return address
  38         ret
  39         SET_SIZE(__builtin_alloca)