path: root/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 hp9000s300
int argc_value;
char **argv_value;
#ifdef OLD_HP_ASSEMBLER
	asm("   text");
	asm("	globl __start");
	asm("	globl _exit");
	asm("	globl _main");
	asm("__start");
	asm("	dc.l	0");
	asm("	subq.w	#0x1,d0");
	asm("	move.w	d0,float_soft");
	asm("	move.l	0x4(a7),d0");
	asm("	beq.s	skip_1");
	asm("	move.l	d0,a0");
	asm("	clr.l	-0x4(a0)");
	asm("skip_1");
	asm("	move.l	a7,a0");
	asm("	subq.l	#0x8,a7");
	asm("	move.l	(a0),(a7)");
	asm("	move.l	(a0),_argc_value");
	asm("	addq.l	#0x4,a0");
	asm("	move.l	a0,0x4(a7)");
	asm("	move.l	a0,_argv_value");
	asm("incr_loop");
	asm("	tst.l	(a0)+");
	asm("	bne.s	incr_loop");
	asm("	move.l	0x4(a7),a1");
	asm("	cmp.l	(a1),a0");
	asm("	blt.s	skip_2");
	asm("	subq.l	#0x4,a0");
	asm("skip_2");
	asm("	move.l	a0,0x8(a7)");
	asm("	move.l	a0,_environ");
	asm("	jsr	_main");
	asm("	addq.l	#0x8,a7");
	asm("	move.l	d0,-(a7)");
	asm("	jsr	_exit");
	asm("	move.w	#0x1,d0");
	asm("	trap	#0x0");
	asm("	comm	float_soft,4");
/* float_soft is allocated in this way because C would
   put an underscore character in its name otherwise. */

#else /* new hp assembler */

	asm("	text");
        asm("   global  float_loc");
        asm("   set     float_loc,0xFFFFB000");
 	asm("	global	fpa_loc");
	asm("	set	fpa_loc,0xfff08000");
	asm("	global	__start");
	asm("	global	_exit");
	asm("	global	_main");
	asm("__start:");
	asm("	byte	0,0,0,0");
	asm("	subq.w	&1,%d0");
	asm("	mov.w	%d0,float_soft");
	asm("	mov.w	%d1,flag_68881");
#ifndef HPUX_68010
	asm("	beq.b	skip_float");
	asm("	fmov.l	&0x7400,%fpcr");
/*	asm("	fmov.l	&0x7480,%fpcr"); */
#endif /* HPUX_68010 */
	asm("skip_float:");
	asm("	mov.l	%a0,%d0");
	asm("	add.l	%d0,%d0");
	asm("	subx.w	%d1,%d1");
	asm("	mov.w	%d1,flag_68010");
	asm("	add.l	%d0,%d0");
	asm("	subx.w	%d1,%d1");
	asm("	mov.w	%d1,flag_fpa");
	asm("	tst.l	%d2");
	asm("	ble.b	skip_3");
	asm("	lsl	flag_68881");
	asm("	lsl	flag_fpa");
	asm("skip_3:");
	asm("	mov.l	4(%a7),%d0");
	asm("	beq.b	skip_1");
	asm("	mov.l	%d0,%a0");
	asm("	clr.l	-4(%a0)");
	asm("skip_1:");
	asm("	mov.l	%a7,%a0");
	asm("	subq.l	&8,%a7");
	asm("	mov.l	(%a0),(%a7)");
	asm("	mov.l	(%a0),_argc_value");
	asm("	addq.l	&4,%a0");
	asm("	mov.l	%a0,4(%a7)");
	asm("	mov.l	%a0,_argv_value");
	asm("incr_loop:");
	asm("	tst.l	(%a0)+");
	asm("	bne.b	incr_loop");
	asm("	mov.l	4(%a7),%a1");
	asm("	cmp.l	%a0,(%a1)");
	asm("	blt.b	skip_2");
	asm("	subq.l	&4,%a0");
	asm("skip_2:");
	asm("	mov.l	%a0,8(%a7)");
	asm("	mov.l	%a0,_environ");
	asm("	jsr	_main");
	asm("	addq.l	&8,%a7");
	asm("	mov.l	%d0,-(%a7)");
	asm("	jsr	_exit");
	asm("	mov.w	&1,%d0");
	asm("	trap	&0");
	asm("	comm	float_soft, 4");
	asm("	comm	flag_68881, 4");
	asm("	comm	flag_68010, 4");
	asm("	comm	flag_68040, 4");
	asm("	comm	flag_fpa, 4");

#endif /* new hp assembler */
#endif /* hp9000s300 */

#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
#ifdef __bsdi__
#include <sys/param.h> /* for version number */
#if defined(_BSDI_VERSION) && (_BSDI_VERSION >= 199501)
char *__progname;
#endif
#endif /* __bsdi__ */

/* arch-tag: 4025c2fb-d6b1-4d29-b1b6-8100b6bd1e74
   (do not change this comment) */