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+/* Startup code compliant to the ELF Xtensa ABI.
+ Copyright (C) 2001, 2007 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 Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ In addition to the permissions in the GNU Lesser General Public
+ License, the Free Software Foundation gives you unlimited
+ permission to link the compiled version of this file with other
+ programs, and to distribute those programs without any restriction
+ coming from the use of this file. (The GNU Lesser General Public
+ License restrictions do apply in other respects; for example, they
+ cover modification of the file, and distribution when not linked
+ into another program.)
+
+ Note that people who make modified versions of this file are not
+ obligated to grant this special exception for their modified
+ versions; it is their choice whether to do so. The GNU Lesser
+ General Public License gives permission to release a modified
+ version without this exception; this exception also makes it
+ possible to release a modified version which carries forward this
+ exception.
+
+ 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
+ Boston, MA 02110-1301, USA. */
+
+#include <features.h>
+
+#ifndef __UCLIBC_CTOR_DTOR__
+ .weak _init
+ .weak _fini
+#endif
+
+/* This is the canonical entry point, usually the first thing in the text
+ segment. When the entry point runs, most register values are unspecified,
+ except for:
+
+ a2 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.
+
+ a1 The stack (i.e., a1+16) contains the arguments and environment:
+ a1+0 argc
+ a1+4 argv[0]
+ ...
+ a1+(4*argc) NULL
+ a1+(4*(argc+1)) envp[0]
+ ...
+ NULL
+
+ Setup parameters accordingly (for a call4). See function prototype
+ from sysdeps/generic/libc-start.c
+
+ a6 = *main
+ a7 = argc
+ a8 = ubp_av
+ a9 = *init
+ a10 = *fini
+ a11 = *rtld_fini
+ [sp+0] = stack_end
+ */
+
+ .text
+ .align 4
+ .literal_position
+ .global _start
+ .type _start, @function
+_start:
+ /* Clear a0 to obviously mark the outermost frame. */
+ movi a0, 0
+
+ /* Load up the user's main function. */
+ movi a6, main
+
+ /* Extract the arguments as encoded on the stack and set up
+ the arguments for `main': argc, argv. envp will be determined
+ later in __uClibc_main. */
+ l32i a7, a1, 0 /* Load the argument count. */
+ addi a8, a1, 4 /* Compute the argv pointer. */
+
+ /* Push address of our own entry points to .fini and .init. */
+ movi a9, _init
+ movi a10, _fini
+
+ /* Setup the shared library termination function. */
+ mov a11, a2
+
+ /* Provide the highest stack address to the user code (for stacks
+ which grow downwards). Note that we destroy the stack version
+ of argc here. */
+ s32i a1, a1, 0
+
+ /* Call the user's main function, and exit with its value.
+ But let the libc call main. */
+ movi a4, __uClibc_main
+ callx4 a4
+
+ /* Crash if somehow `exit' does return. */
+ ill
+
+ /* Define a symbol for the first piece of initialized data. */
+ .data
+ .align 4
+ .global __data_start
+__data_start:
+ .long 0
+ .weak data_start
+ data_start = __data_start