Startup code for ELF binaries on CRIS.

2024-12-27 04:41:02 +08:00 · 2001-04-10 00:22:36 +00:00 · 2001-04-10 00:22:36 +00:00 · cdda3fc7f0
commit cdda3fc7f0
parent 26414026ac
1 changed files with 123 additions and 0 deletions
--- a/sysdeps/cris/elf/start.S
+++ b/sysdeps/cris/elf/start.S
@ -0,0 +1,123 @@
+/* Startup code compliant to the ELF CRIS ABI (to-be-written).
+   Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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>
+
+/* This is the canonical entry point, usually the first thing in the text
+   segment.  When the entry point runs, most registers' values are
+   unspecified, except for:
+
+   R10		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:
+		[SP]			argc
+		[SP+4]			argv[0]
+		...
+		[SP+4*argc]		NULL
+		[SP+4*(argc+1)]		envp[0]
+		...
+					NULL
+*/
+
+	.syntax no_register_prefix
+
+	.text
+	.globl	_start
+_start:
+	/* Clear the frame pointer, to mark the outermost frame.  */
+	moveq	0,r8
+
+	/* Move the shared library termination function to the right place
+	   for __libc_main.  */
+	move.d	r10,r9
+
+	/* Extract the arguments as encoded on the stack and set up the
+	   arguments for `main': argc, argv.  envp will be determined
+	   later in __libc_start_main.  */
+
+	/* Get the argument count.  */
+	move.d	[sp],r11
+
+	/* Store the stack pointer as end of stack.  We overwrite
+	   the incoming argc.  */
+	move.d	sp,[sp]
+
+	/* The argument vector starts just after the argument count.  */
+	move.d	sp,r12
+	addq	4,r12
+
+	/* There are seven arguments to __libc_start_main:
+	   r10:  main - Address of it.
+	   r11:  argc
+	   r12:  argv
+	   r13:  init - Function to call.
+
+	   [sp]: fini - Function to register with atexit.
+           [sp+4]: rtld_fini - Another function to register with atexit.
+	   [sp+8]: stack_end - Top of stack (actually same as argv).
+
+	   The last two are passed on stack.  */
+
+        /* Store the fini function coming from the dynamic loader.  */
+	push	r9
+
+	/* Get the addresses of our own entry points to `.fini' and
+	   `.init'.  */
+
+#ifdef __PIC__
+        /* If for some reason this program is compiled as PIC, set up R0.  */
+	move.d	pc,r0
+	sub.d	.:GOTOFF,r0
+
+	move.d	_init:PLTG,r13
+	add.d	r0,r13
+	move.d	_fini:PLTG,r9
+	add.d	r0,r9
+	move.d	main:PLTG,r10
+	add.d	r0,r10
+#else
+	move.d	_init,r13
+	move.d	_fini,r9
+	move.d	main,r10
+#endif
+	push	r9
+
+	/* Call the user's main function, and exit with its value.  But
+	   let the libc call main.  */
+	PLTCALL	(__libc_start_main)
+
+	/* Crash if somehow `exit' does return.  We have at least 8192
+	   invalid addresses to choose from.  */
+	test.d	[6502]
+
+	/* Stop the unstoppable.  */
+0:
+	ba	0b
+	nop
+
+/* 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