alloca.S revision 1.7
11.7Sross/* $NetBSD: alloca.S,v 1.7 2002/03/23 20:13:35 ross Exp $ */ 21.5Schristos 31.1Scgd/*- 41.1Scgd * Copyright (c) 1990 The Regents of the University of California. 51.1Scgd * All rights reserved. 61.1Scgd * 71.1Scgd * This code is derived from software contributed to Berkeley by 81.1Scgd * William Jolitz. 91.1Scgd * 101.1Scgd * Redistribution and use in source and binary forms, with or without 111.1Scgd * modification, are permitted provided that the following conditions 121.1Scgd * are met: 131.1Scgd * 1. Redistributions of source code must retain the above copyright 141.1Scgd * notice, this list of conditions and the following disclaimer. 151.1Scgd * 2. Redistributions in binary form must reproduce the above copyright 161.1Scgd * notice, this list of conditions and the following disclaimer in the 171.1Scgd * documentation and/or other materials provided with the distribution. 181.1Scgd * 3. All advertising materials mentioning features or use of this software 191.1Scgd * must display the following acknowledgement: 201.1Scgd * This product includes software developed by the University of 211.1Scgd * California, Berkeley and its contributors. 221.1Scgd * 4. Neither the name of the University nor the names of its contributors 231.1Scgd * may be used to endorse or promote products derived from this software 241.1Scgd * without specific prior written permission. 251.1Scgd * 261.1Scgd * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 271.1Scgd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 281.1Scgd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 291.1Scgd * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 301.1Scgd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 311.1Scgd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 321.1Scgd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 331.1Scgd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 341.1Scgd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 351.1Scgd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 361.1Scgd * SUCH DAMAGE. 371.2Sjtc * 381.2Sjtc * from: @(#)alloca.s 5.2 (Berkeley) 5/14/90 391.1Scgd */ 401.1Scgd 411.4Sjtc#include <machine/asm.h> 421.2Sjtc#if defined(LIBC_SCCS) 431.7Sross RCSID("$NetBSD: alloca.S,v 1.7 2002/03/23 20:13:35 ross Exp $") 441.2Sjtc#endif 451.1Scgd 461.6Satatat/* like alloc, but automatic free in return */ 471.1Scgd 481.1ScgdENTRY(alloca) 491.1Scgd popl %edx /* pop return addr */ 501.1Scgd popl %eax /* pop amount to allocate */ 511.1Scgd movl %esp,%ecx 521.1Scgd addl $3,%eax /* round up to next word */ 531.3Smycroft andl $-4,%eax 541.1Scgd subl %eax,%esp 551.1Scgd movl %esp,%eax /* base of newly allocated space */ 561.1Scgd pushl 8(%ecx) /* copy possible saved registers */ 571.1Scgd pushl 4(%ecx) 581.1Scgd pushl 0(%ecx) 591.1Scgd pushl %eax /* dummy to pop at callsite */ 601.7Sross jmp *%edx /* "return" */ 61