BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / csu.tahoe / crt0.c

/*-
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#ifndef lint
static char sccsid[] = "@(#)crt0.c      5.3 (Berkeley) 5/22/91";
#endif /* not lint */

/*
*      C start up routine.
*      Robert Henry, UCB, 20 Oct 81
*
*      We make the following (true) assumptions:
*      1) When the kernel calls start, it does a jump to location 2,
*      and thus avoids the register save mask.  We are NOT called
*      with a calls!
*      2) The only register variable that we can trust is sp,
*      which points to the base of the kernel calling frame.
*/

char **environ = (char **)0;
static int fd;

extern  unsigned char   etext;
extern  unsigned char   eprol asm ("eprol");
extern                  start() asm("start");

/*
* Some kluges: store sp at entry in environ, and
* install 16 bits of 0 at location 0 (a zero register save mask).
* These two hacks remove limits on the use of local
* and register variables in start().
* The reason for using 'moval (sp),...' is that 'movl sp,...' generates
* a privileged instruction trap (argh).
* XXX 'addl3 $start,$2,r0; jmp (r0)' should be replaced with
* XXX 'jbr start+2' when we convert over to gas.
*/
asm(".text; .word 0; moval (sp),_environ; addl3 $start,$2,r0; jmp (r0)");

start()
{
       struct kframe {
               int     kargc;
               char    *kargv[1];      /* size depends on kargc */
               char    kargstr[1];     /* size varies */
               char    kenvstr[1];     /* size varies */
       };
       register struct kframe *kfp;
       register char **targv;
       register char **argv;
       extern int errno;

       kfp = (struct kframe *) environ;
       for (argv = targv = &kfp->kargv[0]; *targv++; /* void */)
               /* void */ ;
       if (targv >= (char **)(*argv))
               --targv;
       environ = targv;
asm("eprol:");

#ifdef MCRT0
       monstartup(&eprol, &etext);
#endif MCRT0
       errno = 0;
       exit(main(kfp->kargc, argv, environ));
}

#ifdef MCRT0
/*ARGSUSED*/
exit(code)
       register int code;
{
       _mcleanup();
       _cleanup();
       _exit(code);
}
#endif MCRT0

#ifdef CRT0
/*
* null mcount and moncontrol,
* just in case some routine is compiled for profiling
*/
moncontrol(val)
       int val;
{

}

mcount()
{

}
#endif CRT0