+
−/* `alloca' standard 4.2 subroutine for 68000's and 16000's and others.
+
−   Copyright (C) 1985, 1986, 1988 Free Software Foundation, Inc.
+
−
+
−This file is part of XEmacs.
+
−
+
−XEmacs is free software: you can redistribute it and/or modify it
+
−under the terms of the GNU General Public License as published by the
+
−Free Software Foundation, either version 3 of the License, or (at your
+
−option) any later version.
+
−
+
−XEmacs is distributed in the hope that it will be useful, but WITHOUT
+
−ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+
−FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+
−for more details.
+
−
+
−You should have received a copy of the GNU General Public License
+
−along with XEmacs.  If not, see <http://www.gnu.org/licenses/>. */
+
−
+
−/* Synched up with: FSF 19.30. */
+
−
+
−/* Both 68000 systems I have run this on have had broken versions of alloca.
+
−   Also, I am told that non-berkeley systems do not have it at all.
+
−   So replace whatever system-provided alloca there may be
+
−   on all 68000 systems.  */
+
−
+
−#define NOT_C_CODE
+
−#ifdef emacs
+
−#include <config.h>
+
−#else
+
−#include "config.h"
+
−#endif
+
−
+
−#ifndef HAVE_ALLOCA  /* define this to use system's alloca */
+
−
+
−#ifndef m68k
+
−#ifndef m68000
+
−you
+
−lose!!
+
−#endif /* m68000 */
+
−#endif /* m68k */
+
−
+
−
+
−#ifdef m68k			/* SGS assembler totally different */
+
−	file	"alloca.s"
+
−	global	alloca
+
−alloca:
+
−	mov.l	(%sp)+,%a1	# pop return addr from top of stack
+
−	mov.l	(%sp)+,%d0	# pop size in bytes from top of stack
+
−	add.l	&R%1,%d0	# round size up to long word
+
−	and.l	&-4,%d0		# mask out lower two bits of size
+
−	sub.l	%d0,%sp		# allocate by moving stack pointer
+
−	tst.b	P%1(%sp)	# stack probe to allocate pages
+
−	mov.l	%sp,%a0		# return pointer as pointer
+
−	mov.l	%sp,%d0		# return pointer as int to avoid disaster
+
−	add.l	&-4,%sp		# new top of stack
+
−	jmp	(%a1)		# not a normal return
+
−	set	S%1,64		# safety factor for C compiler scratch
+
−	set	R%1,3+S%1	# add to size for rounding
+
−	set	P%1,-132	# probe this far below current top of stack
+
−
+
−#else /* not m68k */
+
−
+
−#ifdef m68000
+
−
+
−/* Some systems want the _, some do not.  Win with both kinds.  */
+
−.globl	_alloca
+
−_alloca:
+
−.globl	alloca
+
−alloca:
+
−	movl	sp@+,a0
+
−	movl	a7,d0
+
−	subl	sp@,d0
+
−	andl	#~3,d0
+
−	movl	d0,sp
+
−	tstb	sp@(0)		/* Make stack pages exist  */
+
−				/* Needed on certain systems
+
−				   that lack true demand paging */
+
−	addql	#4,d0
+
−	jmp	a0@
+
−
+
−#endif /* m68000 */
+
−#endif /* not m68k */
+
−
+
−#endif /* not HAVE_ALLOCA */