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/*
Copyright (c) 2013 Andes Technology Corporation.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
The name of the company may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL RED HAT INCORPORATED BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
##==============================================================================
##
## crt1.S
##
## nds32 startup code
##
##==============================================================================
##------------------------------------------------------------------------------
## Vector table setup
##------------------------------------------------------------------------------
.section .nds32_init, "ax"
j _start
##------------------------------------------------------------------------------
## Startup code implementation
##------------------------------------------------------------------------------
.section .text
.weak _SDA_BASE_
.weak _FP_BASE_
.global _start
.type _start, @function
.align 2
_start:
.L_fp_gp_lp_init:
/* Initialization for $fp, $gp, and $lp. The _SDA_BASE_ location
stands for Small Data Access. */
la $fp, _FP_BASE_
la $gp, _SDA_BASE_
movi $lp, #0
.L_stack_init:
/* Initialization for $sp and make sure it is 8-byte aligned. */
la $sp, _stack
movi $r0, #-8 /* Set $r0 as 0xFFFFFFF8. */
and $sp, $sp, $r0
.L_bss_clear:
/* Clear bss section. */
la $r3, _end
la $r0, _edata
beq $r0, $r3, .L_call_main /* Branch if no bss. */
sub $r1, $r3, $r0 /* Size to be clear. */
/* Set $r2 as how many words to be clear.
Set $r1 as how many bytes are less than a woard to be clear. */
srli $r2, $r1, #2
andi $r1, $r1, #3
beqz $r3, .Lbyte_clear
la $r4, #0x00000000
.Lword_clear:
swi.bi $r4, [$r0], #4
addi $r2, $r2, #-1
bnez $r2, .Lword_clear /* Loop again ? */
beqz $r1, .Lend_bss
.Lbyte_clear:
sbi.bi $r4, [$r0], #1
addi $r1, $r1, #-1
bnez $r1, .Lbyte_clear
.Lend_bss:
.L_call_main:
/* Call '_init' to invoke constructors. */
jal _init
/* Register '_fini' into atexit() to invoke destructors when
exit() has been reached. */
la $r0, _fini
jal atexit
/* Call 'main'. */
la $r15, main
jral $r15
.L_terminate_program:
/* There are two ways to terminate program:
1. User "syscall 0x1" directly.
2. Call exit. The return value $r0 from main() is
implicitly passed as argument.
Currently, we use option 2 as a solution to follow C99 5.1.2.2.3,
but aware that general exit() will do some cleanup procedures
which may result in large-memory-footprints. */
la $r15, exit
jral $r15
.L_forever_loop:
/* Should never return here. */
b .L_forever_loop
.size _start, .-_start
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