glibc/sysdeps/sparc/sparc32/elf/start.S

/* Startup code for elf32-sparc
   Copyright (C) 1997 Free Software Foundation, Inc.
   Contributed by Richard Henderson <richard@gnu.ai.mit.edu>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <sysdep.h>


	.section ".text"
	.align 4
	.global _start
	.type _start,#function
_start:

  /* Terminate the stack frame, and reserve space for functions to
     drop their arguments.  */
	mov	%g0, %fp
	sub	%sp, 6*4, %sp

  /* Save %g1.  When starting a binary via the dynamic linker, %g1
     contains the address of the shared library termination function,
     which we will register below with atexit() to be called by exit().
     If we are statically linked, this will be NULL.  */

  /* Do essential libc initialization (sp points to argc, argv, and envp)  */
	call	__libc_init_first
	 mov	%g1, %l0

  /* Now that we have the proper stack frame, register library termination
     function, if there is any:  */

	cmp	%l0, 0
	beq	1f
	 nop
	call	atexit
	 mov	%l0, %o0
1:

  /* Extract the arguments and environment as encoded on the stack.  The
     argument info starts after one register window (16 words) past the SP.  */
	ld	[%sp+22*4], %o0
	add	%sp, 23*4, %o1
	sll	%o0, 2, %o2
	add	%o2, %o1, %o2
	sethi	%hi(__environ), %g2
	add	%o2, 4, %o2
	st	%o2, [%g2+%lo(__environ)]

	mov	%o0, %l0		/* tuck them away */
	mov	%o1, %l1

  /* Call _init, the entry point to our own .init section.  */
	call	_init
	 mov	%o2, %l2

  /* Register our .fini section with atexit.  */
	sethi	%hi(_fini), %o0
	call	atexit
	 add	%o0, %lo(_fini), %o0

  /* Call the user's main and exit with its return value.  */
	mov	%l0, %o0
	mov	%l1, %o1
	call	main
	 mov	%l2, %o2
	call	exit
	 nop

  /* Die very horribly if exit returns.  */
	unimp

	.size _start,.-_start