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crt0.c
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1992-01-28
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/* C code startup routine.
Copyright (C) 1985, 1986 Free Software Foundation, Inc.
This program 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 1, or (at your option)
any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
In other words, you are welcome to use, share and improve this program.
You are forbidden to forbid anyone else to use, share and improve
what you give them. Help stamp out software-hoarding! */
/* The standard Vax 4.2 Unix crt0.c cannot be used for Emacs
because it makes `envron' 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
*/
#include "config.h"
/* ******** 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 DONT_NEED_ENVIRON
char **environ;
#endif
#if defined(orion) || defined(pyramid) || defined(celerity) || defined(ALLIANT) || defined(clipper)
#ifdef ALLIANT
/* _start must initialize _curbrk and _minbrk on the first startup;
when starting up after dumping, it must initialize them to what they were
before the dumping, since they are in the shared library and
are not dumped. See ADJUST_EXEC_HEADER in m-alliant.h. */
extern unsigned char *_curbrk, *_minbrk;
extern unsigned char end;
unsigned char *_setbrk = &end;
#ifdef ALLIANT_2800
unsigned char *_end = &end;
#endif
#endif
#ifndef DUMMIES
#define DUMMIES
#endif
_start (DUMMIES argc, argv, envp)
int argc;
char **argv, **envp;
{
#ifdef ALLIANT
#ifdef ALLIANT_2800
_curbrk = _end;
_minbrk = _end;
#else
_curbrk = _setbrk;
_minbrk = _setbrk;
#endif
#endif
environ = envp;
exit (main (argc, argv, envp));
}
#endif /* orion or pyramid or celerity or alliant or clipper */
#if defined (ns16000) && !defined (sequent) && !defined (UMAX)
_start ()
{
/* On 16000, _start pushes fp onto stack */
start1 ();
}
/* ignore takes care of skipping the fp value pushed in start. */
static
start1 (ignore, argc, argv)
int ignore;
int argc;
register char **argv;
{
environ = argv + argc + 1;
if (environ == *argv)
environ--;
exit (main (argc, argv, environ));
}
#endif /* ns16000, not sequent and not UMAX */
#ifdef UMAX
_start()
{
asm(" exit [] # undo enter");
asm(" .set exitsc,1");
asm(" .set sigcatchall,0x400");
asm(" .globl _exit");
asm(" .globl start");
asm(" .globl __start");
asm(" .globl _main");
asm(" .globl _environ");
asm(" .globl _sigvec");
asm(" .globl sigentry");
asm("start:");
asm(" br .xstart");
asm(" .org 0x20");
asm(" .double p_glbl,0,0xf00000,0");
asm(" .org 0x30");
asm(".xstart:");
asm(" adjspb $8");
asm(" movd 8(sp),0(sp) # argc");
asm(" addr 12(sp),r0");
asm(" movd r0,4(sp) # argv");
asm("L1:");
asm(" movd r0,r1");
asm(" addqd $4,r0");
asm(" cmpqd $0,0(r1) # null args term ?");
asm(" bne L1");
asm(" cmpd r0,0(4(sp)) # end of 'env' or 'argv' ?");
asm(" blt L2");
asm(" addqd $-4,r0 # envp's are in list");
asm("L2:");
asm(" movd r0,8(sp) # env");
asm(" movd r0,@_environ # indir is 0 if no env ; not 0 if env");
asm(" movqd $0,tos # setup intermediate signal handler");
asm(" addr @sv,tos");
asm(" movzwd $sigcatchall,tos");
asm(" jsr @_sigvec");
asm(" adjspb $-12");
asm(" jsr @_main");
asm(" adjspb $-12");
asm(" movd r0,tos");
asm(" jsr @_exit");
asm(" adjspb $-4");
asm(" addr @exitsc,r0");
asm(" svc");
asm(" .align 4 # sigvec arg");
asm("sv:");
asm(" .double sigentry");
asm(" .double 0");
asm(" .double 0");
asm(" .comm p_glbl,1");
}
#endif /* UMAX */
#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 */
static start1 ();
_start ()
{
/* On vax, nothing is pushed here */
/* On sequent, bogus fp is pushed here */
start1 ();
}
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));
}
#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:");
#ifndef NU
#ifdef STRIDE
asm (" comm havefpu%,2");
#else /* m68k, not STRIDE */
asm (" comm splimit%,4");
#endif /* STRIDE */
asm (" global exit");
asm (" text");
#ifdef STRIDE
asm (" trap &3");
asm (" mov.w %d0,havefpu%");
#else /* m68k, not STRIDE */
asm (" mov.l %d0,splimit%");
#endif /* STRIDE */
#endif /* not NU */
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
#ifdef ISI68K
/* Added by ESM Sun May 24 12:44:02 1987 to get new ISI library to work */
#ifdef BSD4_3
static foo () {
#endif
asm (" .globl is68020");
asm ("is68020:");
#ifndef BSD4_3
asm (" .long 0x00000000");
asm (" .long 0xffffffff");
/* End of stuff added by ESM */
#endif
asm (" .text");
asm (" .globl __start");
asm ("__start:");
asm (" .word 0");
asm (" link fp,#0");
asm (" jbsr _start1");
asm (" unlk fp");
asm (" rts");
#ifdef BSD4_3
}
#endif
#else /* not ISI68K */
_start ()
{
/* On 68000, _start pushes a6 onto stack */
start1 ();
}
#endif /* not ISI68k */
#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_fpa, 4");
#endif /* new hp assembler */
#endif /* hp9000s300 */
#ifdef GOULD
/* startup code has to be in near text rather
than fartext as allocated by the C compiler. */
asm(" .text");
asm(" .align 2");
asm(" .globl __start");
asm(" .text");
asm("__start:");
/* setup base register b1 (function base). */
asm(" .using b1,.");
asm(" tpcbr b1");
/* setup base registers b3 through b7 (data references). */
asm(" file basevals,b3");
/* setup base register b2 (stack pointer); it should be
aligned on a 8-word boundary; but because it is pointing
to argc, its value should be remembered (in r5). */
asm(" movw b2,r4");
asm(" movw b2,r5");
asm(" andw #~0x1f,r4");
asm(" movw r4,b2");
/* allocate stack frame to do some work. */
asm(" subea 16w,b2");
/* initialize signal catching for UTX/32 1.2; this is
necessary to make restart from saved image work. */
asm(" movea sigcatch,r1");
asm(" movw r1,8w[b2]");
asm(" svc #1,#150");
/* setup address of argc for start1. */
asm(" movw r5,8w[b2]");
asm(" func #1,_start1");
asm(" halt");
/* space for ld to store base register initial values. */
asm(" .align 5");
asm("basevals:");
asm(" .word __base3,__base4,__base5,__base6,__base7");
static
start1 (xargc)
int *xargc;
{
register int argc;
register char **argv;
argc = *xargc;
argv = (char **)(xargc) + 1;
environ = argv + argc + 1;
if (environ == argv)
environ--;
exit (main (argc, argv, environ));
}
#endif /* GOULD */
#ifdef elxsi
extern int errno;
extern char **environ;
_start()
{
register int r;
errno = 0;
environ = *(&environ + 8);
_stdinit();
r = main(*(&environ + 6), *(&environ + 7), environ);
exit(r);
_exit(r);
}
#endif /* elxsi */
#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 */