194 lines
5.9 KiB
ArmAsm
194 lines
5.9 KiB
ArmAsm
/*
|
|
Copyright (c) 2013-2014 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.
|
|
*/
|
|
|
|
##==============================================================================
|
|
##
|
|
## crt0.S
|
|
##
|
|
## nds32 startup code
|
|
##
|
|
##==============================================================================
|
|
|
|
#include "syscall_extra.h"
|
|
|
|
##------------------------------------------------------------------------------
|
|
## Vector table setup
|
|
##------------------------------------------------------------------------------
|
|
.section .nds32_init, "ax"
|
|
j _start
|
|
|
|
##------------------------------------------------------------------------------
|
|
## Startup code implementation
|
|
##------------------------------------------------------------------------------
|
|
.section .text
|
|
.weak _SDA_BASE_
|
|
.weak _ITB_BASE_
|
|
.weak _arg_init
|
|
.weak __pre_c_init
|
|
.weak __post_c_init
|
|
.weak _call_exit
|
|
.global _start
|
|
.type _start, @function
|
|
.align 2
|
|
_start:
|
|
/* The initialization sequence really does matter !!!
|
|
The global pointer must be
|
|
initialized precedence over all others. */
|
|
|
|
.L_init_gp:
|
|
/* Initialization for global pointer. The symbol _SDA_BASE_ is
|
|
determined by Linker. SDA stands for Small Data Access. */
|
|
la $gp, _SDA_BASE_
|
|
|
|
#if __NDS32_EXT_EX9__
|
|
.L_init_itb:
|
|
/* Initialization for Instruction Table Base (ITB).
|
|
The symbol _ITB_BASE_ is determined by Linker.
|
|
Set $ITB only if MSC_CFG.EIT (cr4.b'24) is set. */
|
|
mfsr $r0, $MSC_CFG
|
|
srli $r0, $r0, 24
|
|
andi $r0, $r0, 0x1
|
|
beqz $r0, 1f /* Fall through ? */
|
|
la $r0, _ITB_BASE_
|
|
mtusr $r0, $ITB
|
|
1:
|
|
#endif
|
|
|
|
.L_init_sp:
|
|
/* Initialization for stack pointer. The symbol _stack is defined
|
|
in linker script. Make sure $sp is 8-byte aligned. */
|
|
la $sp, _stack
|
|
#if __NDS32_ISA_V3__
|
|
bitci $sp, $sp, #7
|
|
#else
|
|
movi $r0, #-8 /* Set $r0 as 0xFFFFFFF8. */
|
|
and $sp, $sp, $r0
|
|
#endif
|
|
|
|
#if __NDS32_EXT_FPU_SP__ || __NDS32_EXT_FPU_DP__
|
|
.L_init_fpu:
|
|
/* Initialize FPU
|
|
Set FUCOP_CTL.CP0EN (fucpr.b'0). */
|
|
mfsr $r0, $FUCOP_CTL
|
|
ori $r0, $r0, 0x1
|
|
mtsr $r0, $FUCOP_CTL
|
|
dsb
|
|
/* According to [bugzilla #9425], set flush-to-zero mode.
|
|
That is, set $FPCSR.DNZ(b'12) = 1. */
|
|
FMFCSR $r0
|
|
ori $r0, $r0, 0x1000
|
|
FMTCSR $r0
|
|
dsb
|
|
#endif
|
|
|
|
.L_pre_c_init:
|
|
! call __pre_c_init if provided
|
|
! sample __pre_c_init is in BSP
|
|
la $r15, __pre_c_init ! load address of __pre_c_init
|
|
beqz $r15, .L_zero_out_bss ! check existence of __pre_c_init
|
|
jral $r15 ! pre-c-runtime initialization
|
|
|
|
.L_zero_out_bss:
|
|
/* Zero out the bss section.
|
|
Equivalence C code for follow part:
|
|
if (_end == _edata) goto .L_post_c_init
|
|
unsinged int *ptr = _edata;
|
|
while (ptr != _end)
|
|
*ptr++ = 0
|
|
$r0 = ptr/_edata
|
|
$r1 = _end
|
|
$r2 = 0
|
|
*/
|
|
la $r0, _edata
|
|
la $r1, _end
|
|
movi $r2, #0
|
|
beq $r0, $r1, .L_post_c_init /* Branch if no bss. */
|
|
.Lword_clear:
|
|
swi.bi $r2, [$r0], #4
|
|
bne $r0, $r1, .Lword_clear
|
|
|
|
.L_post_c_init:
|
|
! call __post_c_init if provided
|
|
! no sample __post_c_init is provided
|
|
la $r15, __post_c_init ! load address of __post_c_init
|
|
beqz $r15, .L_arg_init ! check existence of __post_c_init
|
|
jral $r15 ! post-c-runtime initialization
|
|
|
|
.L_arg_init:
|
|
! argc/argv initialization if necessary
|
|
la $r7, _arg_init ! get address of _arg_init
|
|
beqz $r7, .L_clean_reg ! if there isn't _arg_init, go main
|
|
addi $sp, $sp, -512 ! allocate space for command line
|
|
! and arguments
|
|
move $r6, $sp ! r6 = buffer addr of cmd line
|
|
move $r0, $r6 ! r0 = buffer addr of cmd line
|
|
syscall SYS_getcmdline ! get cmd line
|
|
move $r0, $r6 ! r0 = buffer addr of cmd line
|
|
addi $r1, $r6, 256 ! r1 = argv
|
|
jral $r7 ! init argc/argv
|
|
addi $r1, $r6, 256 ! r1 = argv
|
|
b .L_call_main
|
|
|
|
.L_clean_reg:
|
|
/* Prepare argc/argv/env for main function.
|
|
Since there is no operating system so far,
|
|
we set $r0, $r1, and $r2 to be zero.
|
|
Note: $r2 already set to zero in .L_zero_out_bss: code fragment. */
|
|
movi $r0, 0
|
|
movi $r1, 0
|
|
movi $r2, 0
|
|
|
|
.L_call_main:
|
|
/* Call 'main'. */
|
|
bal main
|
|
|
|
/* Call _call_exit. */
|
|
! call _call_exit if necessary; default implementation is in crtexit.c
|
|
la $r15, _call_exit ! load address of _call_exit
|
|
beqz $r15, .L_terminate_program ! no _call_exit? go exit
|
|
jral $r15 ! _call_exit will never return
|
|
|
|
.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. */
|
|
bal exit
|
|
|
|
.L_forever_loop:
|
|
/* Should never return here. */
|
|
b .L_forever_loop
|
|
|
|
.size _start, .-_start
|