root/usr/src/lib/libc/i386/gen/alloca.S
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
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 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

        .file   "alloca.s"

#include "SYS.h"

        ENTRY(__builtin_alloca)
        popl    %ecx                    / grab our return address
        movl    (%esp),%eax             / get argument
        addl    $3,%eax
        andl    $0xfffffffc,%eax        / round up to multiple of 4
        subl    %eax,%esp               / leave requested space on stack
        leal    4(%esp),%eax            / adjust, accounting for the "size" arg
        pushl   %ecx                    / put back return address
        ret
        SET_SIZE(__builtin_alloca)