1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21/* 22 * Copyright (c) 1998, by Sun Microsystems, Inc. 23 * All rights reserved. 24 */ 25 26 .file "alloca.s" 27 28#include <sys/asm_linkage.h> 29#include <sys/stack.h> 30 31 ! 32 ! o0: # bytes of space to allocate, already rounded to 0 mod 8 33 ! o1: %sp-relative offset of tmp area 34 ! o2: %sp-relative offset of end of tmp area 35 ! 36 ! we want to bump %sp by the requested size 37 ! then copy the tmp area to its new home 38 ! this is necessary as we could theoretically 39 ! be in the middle of a complicated expression. 40 ! 41 ENTRY(__builtin_alloca) 42 add %sp, STACK_BIAS, %g1 ! save current sp + STACK_BIAS 43 sub %sp, %o0, %sp ! bump to new value 44 add %sp, STACK_BIAS, %g5 45 ! copy loop: should do nothing gracefully 46 b 2f 47 subcc %o2, %o1, %o5 ! number of bytes to move 481: 49 ldx [%g1 + %o1], %o4 ! load from old temp area 50 stx %o4, [%g5 + %o1] ! store to new temp area 51 add %o1, 8, %o1 522: bg,pt %xcc, 1b 53 subcc %o5, 8, %o5 54 ! now return new %sp + end-of-temp 55 add %sp, %o2, %o0 56 retl 57 add %o0, STACK_BIAS, %o0 58 SET_SIZE(__builtin_alloca) 59