[unix-history] / usr / src / lib / libc / i386 / gen / alloca.s

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
	.asciz "@(#)alloca.s	5.2 (Berkeley) 5/14/90"
#endif /* LIBC_SCCS and not lint */

/* like alloc, but automatic automatic free in return */

#include "DEFS.h"

ENTRY(alloca)
	popl	%edx		/*  pop return addr */
	popl	%eax		/*  pop amount to allocate */
	movl	%esp,%ecx
	addl	$3,%eax		/*  round up to next word */
	andl	$0xfffffffc,%eax
	subl	%eax,%esp
	movl	%esp,%eax	/* base of newly allocated space */
	pushl	8(%ecx)		/* copy possible saved registers */
	pushl	4(%ecx)
	pushl	0(%ecx)
	pushl	%eax		/* dummy to pop at callsite */
	jmp	%edx		/* "return" */
Commit	Line	Data
33fde5e7 WN	1	/*-
	2	* Copyright (c) 1990 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* William Jolitz.
	7	*
1c15e888 C	8	* Redistribution and use in source and binary forms are permitted
	9	* provided that: (1) source distributions retain this entire copyright
	10	* notice and comment, and (2) distributions including binaries display
	11	* the following acknowledgement: ``This product includes software
	12	* developed by the University of California, Berkeley and its contributors''
	13	* in the documentation or other materials provided with the distribution
	14	* and in all advertising materials mentioning features or use of this
	15	* software. Neither the name of the University nor the names of its
	16	* contributors may be used to endorse or promote products derived
	17	* from this software without specific prior written permission.
	18	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	19	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	20	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
33fde5e7 WN	21	*/
	22
	23	#if defined(LIBC_SCCS) && !defined(lint)
1c15e888	24	.asciz "@(#)alloca.s 5.2 (Berkeley) 5/14/90"
33fde5e7 WN	25	#endif /* LIBC_SCCS and not lint */
	26
	27	/* like alloc, but automatic automatic free in return */
	28
	29	#include "DEFS.h"
	30
	31	ENTRY(alloca)
33fde5e7 WN	32	popl %edx /* pop return addr */
	33	popl %eax /* pop amount to allocate */
	34	movl %esp,%ecx
3608740e	35	addl $3,%eax /* round up to next word */
33fde5e7 WN	36	andl $0xfffffffc,%eax
33fde5e7 WN	37	subl %eax,%esp
3608740e	38	movl %esp,%eax /* base of newly allocated space */
33fde5e7 WN	39	pushl 8(%ecx) /* copy possible saved registers */
	40	pushl 4(%ecx)
	41	pushl 0(%ecx)
	42	pushl %eax /* dummy to pop at callsite */
	43	jmp %edx /* "return" */