/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1998, by Sun Microsystems, Inc.
 * All rights reserved.
 */

        .file   "alloca.s"

#include <sys/asm_linkage.h>
#include <sys/stack.h>

        !
        ! o0: # bytes of space to allocate, already rounded to 0 mod 8
        ! o1: %sp-relative offset of tmp area
        ! o2: %sp-relative offset of end of tmp area
        !
        ! we want to bump %sp by the requested size
        ! then copy the tmp area to its new home
        ! this is necessary as we could theoretically
        ! be in the middle of a complicated expression.
        !
        ENTRY(__builtin_alloca)
        add     %sp, STACK_BIAS, %g1    ! save current sp + STACK_BIAS
        sub     %sp, %o0, %sp           ! bump to new value
        add     %sp, STACK_BIAS, %g5
        ! copy loop: should do nothing gracefully
        b       2f
        subcc   %o2, %o1, %o5           ! number of bytes to move
1:
        ldx     [%g1 + %o1], %o4        ! load from old temp area
        stx     %o4, [%g5 + %o1]        ! store to new temp area
        add     %o1, 8, %o1
2:      bg,pt   %xcc, 1b
        subcc   %o5, 8, %o5
        ! now return new %sp + end-of-temp
        add     %sp, %o2, %o0
        retl
        add     %o0, STACK_BIAS, %o0
        SET_SIZE(__builtin_alloca)