uclibc-ng/libc/sysdeps/linux/sh/crt1.S

/* Startup code for SH & ELF.
   Copyright (C) 1999 Free Software Foundation, Inc.
   Copyright (C) 2001 Hewlett-Packard Australia
   Copyright (C) 2002 Stefan Allius

 This program 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.

 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 Library General Public License for more
 details.

 You should have received a copy of the GNU Library General Public License
 along with this program; if not, see <http://www.gnu.org/licenses/>.
*/


/* This is the canonical entry point, usually the first thing in the text
   segment.

	At this entry point, most registers' values are unspecified, except:

   r4	Contains a function pointer to be registered with `atexit'.
		This is how the dynamic linker arranges to have DT_FINI
		functions called for shared libraries that have been loaded
		before this code runs.

   sp		The stack contains the arguments and environment:
   		0(sp)			argc
		4(sp)			argv[0]
		...
		(4*argc)(sp)		NULL
		(4*(argc+1))(sp)	envp[0]
		...
					NULL
*/

#include <features.h>

	.text
	.globl _start
	.type _start,%function
	.type main,%function
_start:
	/* Clear the frame pointer since this is the outermost frame. */
	mov #0, r14

	/* Pop argc off the stack and save a pointer to argv */
	mov.l @r15+,r5
	mov r15, r6

	/* Push the stack_end, rtld_fini and fini func onto the stack */
	mov.l r6,@-r15
	mov.l r4,@-r15

#ifdef __PIC__
	mova  L_got, r0
	mov.l L_got, r12
	add r0, r12

	mov.l L_fini,r0
	add r12, r0
	mov.l r0,@-r15

	/* Set up the main/init funcs that go in registers */
	mov.l L_main, r4
	add r12, r4
	mov.l L_init, r7
	add r12, r7

	/* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */

	/* Let the libc call main and exit with its return code.  */
	mov.l L_uClibc_main,r0
	mov.l @(r0,r12),r1
	jsr @r1
	nop
	/* We should not get here. */
	mov.l L_abort,r0
	mov.l @(r0,r12),r1
	jsr @r1
	nop
#else
	mov.l L_fini,r0
	mov.l r0,@-r15

	/* Set up the main/init funcs that go in registers */
	mov.l L_main,r4
	mov.l L_init,r7

	/* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */

	/* Let the libc call main and exit with its return code.  */
	mov.l L_uClibc_main,r1
	jsr @r1
	nop
	/* We should not get here. */
	mov.l L_abort,r1
	jmp @r1
	nop
#endif

	.size _start,.-_start
	.align	2

#ifdef __PIC__
L_got:
	.long	_GLOBAL_OFFSET_TABLE_
L_main:
	.long	main@GOTOFF
L_init:
	.long   _init@GOTOFF
L_fini:
	.long   _fini@GOTOFF
L_uClibc_main:
	.long   __uClibc_main@GOT
L_abort:
	.long   abort@GOT
#else
L_main:
	.long   main
L_init:
	.long   _init
L_fini:
	.long   _fini
L_uClibc_main:
	.long   __uClibc_main
L_abort:
	.long   abort
#endif

/* Define a symbol for the first piece of initialized data.  */
	.data
	.globl __data_start
__data_start:
	.long 0
	.weak data_start
	data_start = __data_start