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/* $OpenBSD: crt0.c,v 1.1 2001/06/26 22:42:55 miod Exp $ */
/*
* Mach Operating System
* Copyright (c) 1991, 1992 Carnegie Mellon University
* Copyright (c) 1991, 1992 Omron Corporation
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: crt0.c,v 1.1 2001/06/26 22:42:55 miod Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* Author : Jeffrey Friedl
* Created: July 1992
* Standalone crt0.
*/
/*
* GCCisms used:
* A "volatile void fcn()" is one that never returns.
* register var asm("r1"): variable VAR is raw access to named register.
*/
/*
* When a program begins, r31 points to info passed from the kernel.
*
* The following shows the memory to which r31 points (think "int *r31;"),
* and how we derive argc, argv, and envp from that:
*
* +-------------------+ <-------------------------------------- r31
* | ARGC | <- argc = r31[0];
* +-------------------+ <- argv = &r31[1];
* | &(argument #1) |
* +-------------------+
* | &(argument #2) |
* - - - - - - - - -
* | &(argument #ARGC) |
* +-------------------+
* | 0x00000000 | <- end-of-ARGV-list marker (redundant information).
* +-------------------+ <- environ = envp = &argv[argc+1];
* | &(env. var. #1) |
* +-------------------+
* | &(env. var. #2) |
* - - - - - - - - -
* | &(env. var. #N) |
* +-------------------+
* | 0x00000000 | <- end-of-ENVP-list marker (not redundant!).
* +-------------------+
*
* We use 'start:' to grab r31 and and call real_start(argc, argv, envp).
* We must do this since the function prologue makes finding the initial
* r31 difficult in C.
*/
#include <stdlib.h>
#include "common.h"
asm(" text ");
asm(" align 4 ");
asm("start: global start ");
asm(" ld r2, r31, 0 "); /* First arg to real_start: argc */
asm(" addu r3, r31, 4 "); /* Second arg to real_start: argv */
asm(" lda r4, r3 [r2]"); /* Third arg to real_start: envp, but.... */
asm(" addu r4, r4, 4 "); /* ... don't forget to skip past marker */
asm(" br.n ___crt0_real_start");
asm(" subu r31, r31, 32 ");
#ifdef DYNAMIC
extern struct _dynamic _DYNAMIC;
struct _dynamic *___pdynamic = &_DYNAMIC;
#endif
/* static */ void volatile
__crt0_real_start(int argc, char *argv[], char *envp[])
{
register char *ap;
volatile int a = 0;
extern int end;
environ = envp; /* environ is for the user that can't get at 'envp' */
if (ap = argv[0])
if ((__progname = _strrchr(ap, '/')) == NULL)
__progname = ap;
else
++__progname;
asm ("__callmain:"); /* Defined for the benefit of debuggers */
exit(main(argc, argv, environ));
/*NOTREACHED*/
}
#include "common.c"
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