108 lines
3.0 KiB
ArmAsm

/*
* This file is part of GodMode9
* Copyright (C) 2017-2019 Wolfvak
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that 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.boot
.align 4
#include <arm.h>
#define STACK_SZ (8192)
.global __boot
__boot:
cpsid aif, #SR_SVC_MODE
clrex
@ Writeback and invalidate all DCache
@ Invalidate all caches
@ Data Synchronization Barrier
mov r0, #0
mcr p15, 0, r0, c7, c10, 0
mcr p15, 0, r0, c7, c7, 0
mcr p15, 0, r0, c7, c10, 4
@ Reset control registers
ldr r0, =0x00054078
ldr r1, =0x0000000F
ldr r2, =0x00F00000
mcr p15, 0, r0, c1, c0, 0
mcr p15, 0, r1, c1, c0, 1
mcr p15, 0, r2, c1, c0, 2
@ VFPv2 init
@ https://github.com/derrekr/fastboot3DS/blob/f63c967369451b1fd0078e649cf0010fe10a62fd/source/arm11/start.s#L195
mov r0, #0
mov r1, #0xF00000 @ Give full access to cp10/11 in user and privileged mode
mov r2, #0x40000000 @ Clear exception bits and enable VFP11
mov r3, #0x3C00000 @ Round towards zero (RZ) mode, flush-to-zero mode, default NaN mode
mcr p15, 0, r1, c1, c0, 2 @ Write Coprocessor Access Control Register
mcr p15, 0, r0, c7, c5, 4 @ Flush Prefetch Buffer
fmxr fpexc, r2 @ Write Floating-point exception register
fmxr fpscr, r3 @ Write Floating-Point Status and Control Register
@ Get CPU ID
mrc p15, 0, r12, c0, c0, 5
ands r12, r12, #3
@ Setup stack according to CPU ID
ldr sp, =(_stack_base + STACK_SZ)
ldr r0, =STACK_SZ
mla sp, r0, r12, sp
beq corezero_start
cmp r12, #MAX_CPU
blo coresmp_start
1:
wfi
b 1b
corezero_start:
@ assumes the .bss section size is 128 byte aligned (or zero)
ldr r0, =__bss_pa
ldr r1, =__bss_va_end @ calculate the length of .bss using the VA start and end
ldr r2, =__bss_va
sub r1, r1, r2
add r1, r0, r1 @ fixup to be PA start and end
mov r2, #0
mov r3, #0
mov r4, #0
mov r5, #0
.Lclearbss:
cmp r0, r1
.rept (128 / 16) @ 16 bytes copied per block
stmloia r0!, {r2-r5}
.endr
blo .Lclearbss
bl SYS_CoreZeroInit
coresmp_start:
bl SYS_CoreInit
ldr lr, =MainLoop
bx lr
.section .bss.stack
.align 12 @ make sure stack is aligned to a page boundary
.global _stack_base
_stack_base:
.space (MAX_CPU * STACK_SZ)