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/*
* Copyright (c) 2018 naehrwert
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
.section .text._start
.arm
.extern _reloc_ipl
.type _reloc_ipl, %function
.extern memset
.type memset, %function
.extern loader_main
.type loader_main, %function
.globl _start
.type _start, %function
_start:
ADR R0, _start
LDR R1, =__ipl_start
CMP R0, R1
BEQ _real_start
/* If we are not in the right location already, copy a relocator to upper IRAM. */
ADR R2, _reloc_ipl
LDR R3, =0x4003FF00
MOV R4, #(_real_start - _reloc_ipl)
_copy_loop:
LDMIA R2!, {R5}
STMIA R3!, {R5}
SUBS R4, #4
BNE _copy_loop
/* Use the relocator to copy ourselves into the right place. */
LDR R2, =__ipl_end
SUB R2, R2, R1
LDR R3, =_real_start
LDR R4, =0x4003FF00
BX R4
_reloc_ipl:
LDMIA R0!, {R4-R7}
STMIA R1!, {R4-R7}
SUBS R2, #0x10
BNE _reloc_ipl
/* Jump to the relocated entry. */
BX R3
_real_start:
/* Initially, we place our stack in IRAM but will move it to SDRAM later. */
LDR SP, =0x40007000
LDR R0, =__ldr_end
BL loader_main
B .
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
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