1/* $NetBSD$ */ 2 3/*- 4 * Copyright (c) 1990 The Regents of the University of California. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * William Jolitz. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)alloca.s 5.2 (Berkeley) 5/14/90 35 */ 36 37#include <machine/asm.h> 38#if defined(LIBC_SCCS) 39 RCSID("$NetBSD$") 40#endif 41 42/* like alloc, but automatic free in return */ 43 44ENTRY(alloca) 45 popl %edx /* pop return addr */ 46 popl %eax /* pop amount to allocate */ 47 movl %esp,%ecx 48 addl $3,%eax /* round up to next word */ 49 andl $-4,%eax 50 subl %eax,%esp 51 movl %esp,%eax /* base of newly allocated space */ 52 pushl 8(%ecx) /* copy possible saved registers */ 53 pushl 4(%ecx) 54 pushl 0(%ecx) 55 pushl %eax /* dummy to pop at callsite */ 56 jmp *%edx /* "return" */ 57END(alloca) 58