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alloca.S revision 1.4.56.1 
      1     /*	$NetBSD: alloca.S,v 1.4.56.1 2014/08/20 00:02:09 tls Exp $	*/
      2     
      3     /*
      4      * Copyright (c) 1995 Mark Brinicombe
      5      * All rights reserved.
      6      *
      7      * Redistribution and use in source and binary forms, with or without
      8      * modification, are permitted provided that the following conditions
      9      * are met:
     10      * 1. Redistributions of source code must retain the above copyright
     11      *    notice, this list of conditions and the following disclaimer.
     12      * 2. Redistributions in binary form must reproduce the above copyright
     13      *    notice, this list of conditions and the following disclaimer in the
     14      *    documentation and/or other materials provided with the distribution.
     15      * 3. All advertising materials mentioning features or use of this software
     16      *    must display the following acknowledgement:
     17      *	This product includes software developed by Mark Brinicombe
     18      * 4. 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 AUTHOR 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 AUTHOR 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     
     35     /* like alloc, but automatic automatic free in return */
     36     
     37     #include <machine/asm.h>
     38     
     39     ENTRY(alloca)
     40     	adds	r0, r0, #7	/* round up to next 8 byte alignment */
     41     #if !defined(__thumb__) || defined(_ARM_ARCH_T2)
     42     	bics	r0, r0, #7
     43     	sub	sp, sp, r0	/* Adjust the stack pointer */
     44     	mov	r0, sp		/* r0 = base of new space */
     45     #else
     46     	lsrs	r0, r0, #3
     47     	lsls	r0, r0, #3
     48     	mov	r1, sp
     49     	subs	r0, r1, r0	/* Adjust the stack pointer */
     50     	mov	sp, r0		/* r0 = base of new space */
     51     #endif
     52     	RET
     53     END(alloca)
     54