Wolfvak 016eac6982 - properly set up MMU tables with caching and other fun stuff
- maps a regular ARM-style exception vector table instead of using the bootrom vector redirection

features a ton of bugs because I'm missing something, it actually manages to boot fb3DS v1.2 and BAX fine, but fails to boot itself
2019-06-03 02:27:41 +02:00

67 lines
1.1 KiB
ArmAsm

.section .text.boot
.align 4
#include <arm.h>
#define STACK_SZ (8192)
.global __boot
__boot:
cpsid aif, #SR_SVC_MODE
@ 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
@ 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:
ldr r0, =__bss_pa
ldr r1, =__bss_len
mov r2, #0
add r1, r0, r1
.Lclearbss:
cmp r0, r1
strlt r2, [r0], #4
blt .Lclearbss
coresmp_start:
bl SYS_CoreInit
bl MPCoreMain
b __boot
.section .bss.stack
.align 3
_stack_base:
.space (MAX_CPU * STACK_SZ)