1/* $NetBSD: alloca.S,v 1.9 2013/07/17 04:57:55 matt Exp $ */ 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 * the Systems Programming Group of the University of Utah Computer 9 * Science Department. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36#include <machine/asm.h> 37 38#if defined(LIBC_SCCS) && !defined(lint) 39#if 0 40 RCSID("from: @(#)alloca.s 5.1 (Berkeley) 5/12/90") 41#else 42 RCSID("$NetBSD: alloca.S,v 1.9 2013/07/17 04:57:55 matt Exp $") 43#endif 44#endif /* LIBC_SCCS and not lint */ 45 46/* like alloc, but automatic free in return */ 47 48ENTRY(alloca) 49 movl (%sp),%a1 /* save return addr */ 50 movl %sp,%d0 /* get current SP value */ 51 subl 4(%sp),%d0 /* allocate requested space */ 52 movql #-4,%d1 /* sign extend a mask */ 53 andl %d1,%d0 /* longword align for efficiency */ 54 addql #8,%d0 /* reuse space of call frame */ 55 movl %d0,%sp /* set new SP value */ 56 subql #4,%sp /* account for argument pop in caller */ 57#ifdef __SVR4_ABI__ 58 moveal %d0,%a0 59#endif 60 jmp (%a1) /* funny return */ 61END(alloca) 62