xref: /titanic_50/usr/src/lib/libc/amd64/gen/alloca.s (revision 9a70fc3be3b1e966bf78825cdb8d509963a6f0a1)
17c478bd9Sstevel@tonic-gate/*
27c478bd9Sstevel@tonic-gate * CDDL HEADER START
37c478bd9Sstevel@tonic-gate *
47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*9a70fc3bSMark J. Nelson * Common Development and Distribution License (the "License").
6*9a70fc3bSMark J. Nelson * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate *
87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate * and limitations under the License.
127c478bd9Sstevel@tonic-gate *
137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate *
197c478bd9Sstevel@tonic-gate * CDDL HEADER END
207c478bd9Sstevel@tonic-gate */
217c478bd9Sstevel@tonic-gate/*
227c478bd9Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
237c478bd9Sstevel@tonic-gate * Use is subject to license terms.
247c478bd9Sstevel@tonic-gate */
257c478bd9Sstevel@tonic-gate
26*9a70fc3bSMark J. Nelson	.file	"alloca.s"
277c478bd9Sstevel@tonic-gate
287c478bd9Sstevel@tonic-gate#include "SYS.h"
297c478bd9Sstevel@tonic-gate
307c478bd9Sstevel@tonic-gate	ENTRY(__builtin_alloca)
317c478bd9Sstevel@tonic-gate	popq	%rcx			/* grab our return address */
327c478bd9Sstevel@tonic-gate	addq	$15, %rdi		/* round size up to multiple of 16 */
337c478bd9Sstevel@tonic-gate	andq	$0xfffffffffffffff0, %rdi
347c478bd9Sstevel@tonic-gate	subq	%rdi, %rsp		/* allocate requested space on stack */
357c478bd9Sstevel@tonic-gate	movq	%rsp, %rax		/* pointer to new memory block */
367c478bd9Sstevel@tonic-gate	jmp	*%rcx			/* return */
377c478bd9Sstevel@tonic-gate	SET_SIZE(__builtin_alloca)
38