shared/start/rtems_crti.S

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*
0004  * Copyright (c) 2017 embedded brains GmbH & Co. KG
0005  *
0006  * Redistribution and use in source and binary forms, with or without
0007  * modification, are permitted provided that the following conditions
0008  * are met:
0009  * 1. Redistributions of source code must retain the above copyright
0010  *    notice, this list of conditions and the following disclaimer.
0011  * 2. Redistributions in binary form must reproduce the above copyright
0012  *    notice, this list of conditions and the following disclaimer in the
0013  *    documentation and/or other materials provided with the distribution.
0014  *
0015  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0016  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0017  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0018  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0019  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0020  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0021  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0024  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0025  * POSSIBILITY OF SUCH DAMAGE.
0026  */
0027
0028 /* rtems_crti.S */
0029 #include <rtems/asm.h>
0030 #include <rtems/score/cpu.h>
0031
0032 #if defined(__powerpc64__)
0033     .section ".init","ax"
0034     .align 2
0035     .globl  _init
0036     .type   _init,@function
0037 _init:
0038     mflr    r0
0039     std r0,16(1)
0040     stdu    r1,-96(1)
0041
0042     .section ".fini","ax"
0043     .align 2
0044     .globl  _fini
0045     .type   _fini,@function
0046 _fini:
0047     mflr    r0
0048     std r0,16(r1)
0049     stdu    r1,-96(r1)
0050 #else
0051     /* terminate the __init() function and create
0052      * a new head '_init' for use by RTEMS to
0053      * invoke C++ global constructors
0054      * NOTE: it is essential that this snippet
0055      * is hooked between ecrti and crtbegin
0056      *
0057      * ecrti has the following .init section:
0058      * __init:
0059      *    stwu r1,-16(r1)
0060      *    mflr r0
0061      *    stw  r0,20(r1)
0062      *
0063      * The reason for this is that we want to call
0064      * __eabi() at an early stage but prevent __eabi()
0065      * from branching to __init (C++ exception init
0066      * and global CTORs). Hence we make __init a no-op
0067      * and create a new entry point:
0068      */
0069     .section ".init","ax"
0070     .align 2
0071     lwz     r0,r20(r1)
0072     mtlr    r0
0073     addi    r1,r1,16
0074     blr
0075     .globl  _init
0076     .type   _init,@function
0077 _init:
0078     stwu    r1,-16(r1)
0079     mflr    r0
0080     stw     r0,20(r1)
0081 #endif