Atmosphere/fusee/fusee-primary/src/start.s

62 lines
1.6 KiB
ArmAsm

/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* 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/>.
*/
.macro CLEAR_GPR_REG_ITER
mov r\@, #0
.endm
.section .text.start, "ax", %progbits
.arm
.align 5
.global _start
.type _start, %function
_start:
/* Switch to system mode, mask all interrupts, clear all flags */
msr cpsr_cxsf, #0xDF
/* Relocate loader stub. */
ldr r0, =_start
adr r1, _start
ldr r2, =__loader_stub_lma__
sub r2, r2, r0
add r2, r2, r1
ldr r3, =__loader_stub_start__
ldr r4, =__loader_stub_end__
sub r4, r4, r3
_relocation_loop:
ldmia r2!, {r5-r12}
stmia r3!, {r5-r12}
subs r4, #0x20
bne _relocation_loop
/* Set the stack pointer */
ldr sp, =__stack_top__
mov fp, #0
/* Generate arguments. */
ldr r3, =fusee_primary_main_lz4
ldr r4, =fusee_primary_main_lz4_end
sub r4, r4, r3
sub r3, r3, r0
add r3, r3, r1
mov r0, r3
mov r1, r4
/* Jump to the loader stub. */
ldr r3, =load_fusee_primary_main
bx r3