[bpt/emacs.git] / src / ecrt0.c

/* C code startup routine.
   Copyright (C) 1985, 1986, 1992, 2001, 2002, 2003, 2004,
                 2005, 2006, 2007, 2008 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs 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.

GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */


/* The standard Vax 4.2 Unix crt0.c cannot be used for Emacs
   because it makes `environ' an initialized variable.
   It is easiest to have a special crt0.c on all machines
   though I don't know whether other machines actually need it.  */

/* On the vax and 68000, in BSD4.2 and USG5.2,
   this is the data format on startup:
  (vax) ap and fp are unpredictable as far as I know; don't use them.
  sp ->  word containing argc
         word pointing to first arg string
	 [word pointing to next arg string]... 0 or more times
	 0
Optionally:
	 [word pointing to environment variable]... 1 or more times
	 ...
	 0
And always:
	 first arg string
	 [next arg string]... 0 or more times
*/

/* On the 16000, at least in the one 4.2 system I know about,
  the initial data format is
  sp ->  word containing argc
         word containing argp
         word pointing to first arg string, and so on as above
*/

#ifdef emacs
#include <config.h>
#endif

/*		********  WARNING ********
    Do not insert any data definitions before data_start!
    Since this is the first file linked, the address of the following
    variable should correspond to the start of initialized data space.
    On some systems this is a constant that is independent of the text
    size for shared executables.  On others, it is a function of the
    text size. In short, this seems to be the most portable way to
    discover the start of initialized data space dynamically at runtime,
    for either shared or unshared executables, on either swapping or
    virtual systems.  It only requires that the linker allocate objects
    in the order encountered, a reasonable model for most Unix systems.
    Similarly, note that the address of _start() should be the start
    of text space.   Fred Fish, UniSoft Systems Inc.  */

int data_start = 0;

#ifdef NEED_ERRNO
int errno;
#endif

#ifndef MSDOS
char **environ;
#endif

#ifndef static
/* On systems where the static storage class is usable, this function
   should be declared as static.  Otherwise, the static keyword has
   been defined to be something else, and code for those systems must
   take care of this declaration appropriately.  */
static start1 ();
#endif

#ifdef CRT0_DUMMIES

/* Define symbol "start": here; some systems want that symbol.  */
#ifdef DOT_GLOBAL_START
asm("	.text		");
asm("	.globl start	");
asm("	start:		");
#endif /* DOT_GLOBAL_START */

#ifdef NODOT_GLOBAL_START
asm("	text		");
asm("	global start	");
asm("	start:		");
#endif /* NODOT_GLOBAL_START */

#ifdef m68000

/* GCC 2.1, when optimization is turned off, seems to want to push a
   word of garbage on the stack, which screws up the CRT0_DUMMIES
   hack.  So we hand-code _start in assembly language.  */
asm(".text			");
asm("	.even			");
asm(".globl __start		");
asm("__start:			");
asm("	link a6,#0		");
asm("	jbsr _start1		");
asm("	unlk a6			");
asm("	rts			");

#else /* not m68000 */

_start ()
{
/* On vax, nothing is pushed here  */
/* On sequent, bogus fp is pushed here  */
  start1 ();
}

#endif /* possibly m68000 */

static
start1 (CRT0_DUMMIES argc, xargv)
     int argc;
     char *xargv;
{
  register char **argv = &xargv;
  environ = argv + argc + 1;

  if ((char *)environ == xargv)
    environ--;
  exit (main (argc, argv, environ));

  /* Refer to `start1' so GCC will not think it is never called
     and optimize it out.  */
  (void) &start1;
}
#else /* not CRT0_DUMMIES */

/* "m68k" and "m68000" both stand for m68000 processors,
   but with different program-entry conventions.
   This is a kludge.  Now that the CRT0_DUMMIES mechanism above exists,
   most of these machines could use the vax code above
   with some suitable definition of CRT0_DUMMIES.
   Then the symbol m68k could be flushed.
   But I don't want to risk breaking these machines
   in a version 17 patch release, so that change is being put off.  */

#ifdef m68k			/* Can't do it all from C */
	asm ("	global	_start");
	asm ("	text");
	asm ("_start:");
	asm ("  comm	splimit%,4");
	asm ("	global	exit");
	asm ("	text");
  	asm ("	mov.l	%d0,splimit%");
	asm ("	jsr	start1");
	asm ("	mov.l	%d0,(%sp)");
	asm ("	jsr	exit");
	asm ("	mov.l	&1,%d0");	/* d0 = 1 => exit */
	asm ("	trap	&0");
#else /* m68000, not m68k */

#ifdef m68000

_start ()
{
#ifdef sun
  finitfp_();
#endif
/* On 68000, _start pushes a6 onto stack  */
  start1 ();
}
#endif /* m68000 */
#endif /* m68k */

#if defined(m68k) || defined(m68000)
/* ignore takes care of skipping the a6 value pushed in start.  */
static
#if defined(m68k)
start1 (argc, xargv)
#else
start1 (ignore, argc, xargv)
#endif
     int argc;
     char *xargv;
{
  register char **argv = &xargv;
  environ = argv + argc + 1;

  if ((char *)environ == xargv)
    environ--;
  exit (main (argc, argv, environ));
}

#endif /* m68k or m68000 */

#endif /* not CRT0_DUMMIES */

#ifdef sparc
asm (".global __start");
asm (".text");
asm ("__start:");
asm ("	mov	0, %fp");
asm ("	ld	[%sp + 64], %o0");
asm ("	add	%sp, 68, %o1");
asm ("	sll	%o0, 2,	%o2");
asm ("	add	%o2, 4,	%o2");
asm ("	add	%o1, %o2, %o2");
asm ("	sethi	%hi(_environ), %o3");
asm ("	st	%o2, [%o3+%lo(_environ)]");
asm ("	andn	%sp, 7,	%sp");
asm ("	call	_main");
asm ("	sub	%sp, 24, %sp");
asm ("	call	__exit");
asm ("	nop");

#endif /* sparc */

#if __FreeBSD__ == 2
char *__progname;
#endif

/* arch-tag: 4025c2fb-d6b1-4d29-b1b6-8100b6bd1e74
   (do not change this comment) */
Commit	Line	Data
b8098ef8	1	/* C code startup routine.
429ab54e	2	Copyright (C) 1985, 1986, 1992, 2001, 2002, 2003, 2004,
8cabe764	3	2005, 2006, 2007, 2008 Free Software Foundation, Inc.
b8098ef8 DL	4
	5	This file is part of GNU Emacs.
	6
9ec0b715	7	GNU Emacs is free software: you can redistribute it and/or modify
b8098ef8	8	it under the terms of the GNU General Public License as published by
9ec0b715 GM	9	the Free Software Foundation, either version 3 of the License, or
9ec0b715 GM	10	(at your option) any later version.
b8098ef8 DL	11
	12	GNU Emacs is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
9ec0b715	18	along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
b8098ef8 DL	19
	20
	21	/* The standard Vax 4.2 Unix crt0.c cannot be used for Emacs
	22	because it makes `environ' an initialized variable.
	23	It is easiest to have a special crt0.c on all machines
	24	though I don't know whether other machines actually need it. */
	25
	26	/* On the vax and 68000, in BSD4.2 and USG5.2,
	27	this is the data format on startup:
	28	(vax) ap and fp are unpredictable as far as I know; don't use them.
	29	sp -> word containing argc
	30	word pointing to first arg string
	31	[word pointing to next arg string]... 0 or more times
	32	0
	33	Optionally:
	34	[word pointing to environment variable]... 1 or more times
	35	...
	36	0
	37	And always:
	38	first arg string
	39	[next arg string]... 0 or more times
	40	*/
	41
	42	/* On the 16000, at least in the one 4.2 system I know about,
	43	the initial data format is
	44	sp -> word containing argc
	45	word containing argp
	46	word pointing to first arg string, and so on as above
	47	*/
	48
	49	#ifdef emacs
	50	#include <config.h>
	51	#endif
	52
	53	/* ****** WARNING ******
	54	Do not insert any data definitions before data_start!
	55	Since this is the first file linked, the address of the following
	56	variable should correspond to the start of initialized data space.
	57	On some systems this is a constant that is independent of the text
	58	size for shared executables. On others, it is a function of the
	59	text size. In short, this seems to be the most portable way to
	60	discover the start of initialized data space dynamically at runtime,
	61	for either shared or unshared executables, on either swapping or
	62	virtual systems. It only requires that the linker allocate objects
	63	in the order encountered, a reasonable model for most Unix systems.
	64	Similarly, note that the address of _start() should be the start
	65	of text space. Fred Fish, UniSoft Systems Inc. */
	66
	67	int data_start = 0;
	68
	69	#ifdef NEED_ERRNO
	70	int errno;
	71	#endif
	72
4624371d	73	#ifndef MSDOS
b8098ef8 DL	74	char **environ;
	75	#endif
	76
	77	#ifndef static
	78	/* On systems where the static storage class is usable, this function
	79	should be declared as static. Otherwise, the static keyword has
	80	been defined to be something else, and code for those systems must
	81	take care of this declaration appropriately. */
	82	static start1 ();
	83	#endif
	84
b8098ef8 DL	85	#ifdef CRT0_DUMMIES
	86
	87	/* Define symbol "start": here; some systems want that symbol. */
	88	#ifdef DOT_GLOBAL_START
	89	asm(" .text ");
	90	asm(" .globl start ");
	91	asm(" start: ");
	92	#endif /* DOT_GLOBAL_START */
	93
	94	#ifdef NODOT_GLOBAL_START
	95	asm(" text ");
	96	asm(" global start ");
	97	asm(" start: ");
	98	#endif /* NODOT_GLOBAL_START */
	99
	100	#ifdef m68000
	101
	102	/* GCC 2.1, when optimization is turned off, seems to want to push a
	103	word of garbage on the stack, which screws up the CRT0_DUMMIES
	104	hack. So we hand-code _start in assembly language. */
	105	asm(".text ");
	106	asm(" .even ");
	107	asm(".globl __start ");
	108	asm("__start: ");
	109	asm(" link a6,#0 ");
	110	asm(" jbsr _start1 ");
	111	asm(" unlk a6 ");
	112	asm(" rts ");
	113
	114	#else /* not m68000 */
	115
	116	_start ()
	117	{
	118	/* On vax, nothing is pushed here */
	119	/* On sequent, bogus fp is pushed here */
	120	start1 ();
	121	}
	122
	123	#endif /* possibly m68000 */
	124
	125	static
	126	start1 (CRT0_DUMMIES argc, xargv)
	127	int argc;
	128	char *xargv;
	129	{
	130	register char **argv = &xargv;
	131	environ = argv + argc + 1;
	132
	133	if ((char *)environ == xargv)
	134	environ--;
	135	exit (main (argc, argv, environ));
	136
	137	/* Refer to `start1' so GCC will not think it is never called
	138	and optimize it out. */
	139	(void) &start1;
	140	}
	141	#else /* not CRT0_DUMMIES */
	142
	143	/* "m68k" and "m68000" both stand for m68000 processors,
	144	but with different program-entry conventions.
	145	This is a kludge. Now that the CRT0_DUMMIES mechanism above exists,
	146	most of these machines could use the vax code above
	147	with some suitable definition of CRT0_DUMMIES.
	148	Then the symbol m68k could be flushed.
149	But I don't want to risk breaking these machines
150	in a version 17 patch release, so that change is being put off. */
151
152	#ifdef m68k /* Can't do it all from C */
153	asm (" global _start");
154	asm (" text");
155	asm ("_start:");
b8098ef8	156	asm (" comm splimit%,4");
b8098ef8 DL	157	asm (" global exit");
b8098ef8 DL	158	asm (" text");
b8098ef8	159	asm (" mov.l %d0,splimit%");
b8098ef8 DL	160	asm (" jsr start1");
	161	asm (" mov.l %d0,(%sp)");
	162	asm (" jsr exit");
	163	asm (" mov.l &1,%d0"); /* d0 = 1 => exit */
	164	asm (" trap &0");
	165	#else /* m68000, not m68k */
	166
	167	#ifdef m68000
	168
b8098ef8 DL	169	_start ()
	170	{
	171	#ifdef sun
b8098ef8	172	finitfp_();
177c0ea7	173	#endif
b8098ef8 DL	174	/* On 68000, _start pushes a6 onto stack */
	175	start1 ();
	176	}
b8098ef8 DL	177	#endif /* m68000 */
	178	#endif /* m68k */
	179
	180	#if defined(m68k) \|\| defined(m68000)
	181	/* ignore takes care of skipping the a6 value pushed in start. */
	182	static
	183	#if defined(m68k)
	184	start1 (argc, xargv)
	185	#else
	186	start1 (ignore, argc, xargv)
	187	#endif
	188	int argc;
	189	char *xargv;
	190	{
	191	register char **argv = &xargv;
	192	environ = argv + argc + 1;
	193
	194	if ((char *)environ == xargv)
	195	environ--;
b8098ef8 DL	196	exit (main (argc, argv, environ));
	197	}
	198
	199	#endif /* m68k or m68000 */
	200
	201	#endif /* not CRT0_DUMMIES */
	202
b8098ef8 DL	203	#ifdef sparc
	204	asm (".global __start");
	205	asm (".text");
	206	asm ("__start:");
	207	asm (" mov 0, %fp");
	208	asm (" ld [%sp + 64], %o0");
	209	asm (" add %sp, 68, %o1");
	210	asm (" sll %o0, 2, %o2");
	211	asm (" add %o2, 4, %o2");
	212	asm (" add %o1, %o2, %o2");
	213	asm (" sethi %hi(_environ), %o3");
	214	asm (" st %o2, [%o3+%lo(_environ)]");
	215	asm (" andn %sp, 7, %sp");
	216	asm (" call _main");
	217	asm (" sub %sp, 24, %sp");
	218	asm (" call __exit");
	219	asm (" nop");
	220
	221	#endif /* sparc */
	222
	223	#if __FreeBSD__ == 2
	224	char *__progname;
	225	#endif
ab5796a9 MB	226
	227	/* arch-tag: 4025c2fb-d6b1-4d29-b1b6-8100b6bd1e74
	228	(do not change this comment) */