211 lines
6.8 KiB
ArmAsm

/*
* This file is part of open_agb_firm
* Copyright (C) 2021 derrek, profi200
*
* 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 3 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/>.
*/
#include "asm_macros.h"
#include "arm.h"
#include "mem_map.h"
#include "arm11/drivers/performance_monitor.h"
.syntax unified
.cpu mpcore
.fpu vfpv2
.section .crt0, "ax", %progbits
BEGIN_ASM_FUNC vectors no_section
ldr pc, resetHandlerPtr @ Reset vector
ldr pc, undefInstrHandlerPtr @ Undefined instruction vector
udf #3 @ Software interrupt (SVC) vector
ldr pc, prefetchAbortHandlerPtr @ Prefetch abort vector
ldr pc, dataAbortHandlerPtr @ Data abort vector
udf #6 @ Reserved (unused) vector
ldr pc, irqHandlerPtr @ Interrupt (IRQ) vector
udf #8 @ Fast interrupt (FIQ) vector
resetHandlerPtr: .4byte _start
undefInstrHandlerPtr: .4byte undefInstrHandler
@svcHandlerPtr: .4byte (vectors + 0x08)
prefetchAbortHandlerPtr: .4byte prefetchAbortHandler
dataAbortHandlerPtr: .4byte dataAbortHandler
irqHandlerPtr: .4byte irqHandler
@fiqHandlerPtr: .4byte (vectors + 0x1C)
END_ASM_FUNC
BEGIN_ASM_FUNC _start no_section
cpsid aif, #PSR_SVC_MODE
@ Control register:
@ [29] Force AP functionality : disabled
@ [28] TEX remap : disabled
@ [27] NMFI bit : normal FIQ behavior
@ [25] CPSR E bit on taking an exception : 0
@ [23] Extended page table configuration : subpage AP bits enabled
@ [22] Unaligned data access : disabled
@ [15] Disable loading TBIT : disabled
@ [13] Vector select : 0x00000000
@ [12] Level one instruction cache : enabled
@ [11] Program flow prediction : disabled
@ [7] Endianess : little
@ [2] Level one data cache : disabled
@ [1] Strict data address alignment fault: disabled
@ [0] MMU : disabled
ldr r3, =0x55078
mov r4, #0
mcr p15, 0, r3, c1, c0, 0 @ Write control register
mcr p15, 0, r4, c1, c0, 1 @ Write Auxiliary Control Register
mcr p15, 0, r4, c7, c7, 0 @ Invalidate Both Caches. Also flushes the branch target cache
mcr p15, 0, r4, c7, c10, 4 @ Data Synchronization Barrier
mcr p15, 0, r4, c7, c5, 4 @ Flush Prefetch Buffer
clrex
mrc p15, 0, r4, c0, c0, 5 @ Get CPU ID
ands r4, r4, #3
bleq stubExceptionVectors @ Stub the vectors in AXIWRAM bootrom vectors jump to
mov sp, #0 @ unused SVC mode sp
cps #PSR_FIQ_MODE
mov sp, #0 @ Unused
cps #PSR_IRQ_MODE
mov sp, #0 @ not needed
ldr r0, =A11_EXC_STACK_END
cps #PSR_ABORT_MODE
mov sp, r0
cps #PSR_UNDEF_MODE
mov sp, r0
cps #PSR_SYS_MODE
adr r2, _sysmode_stacks
ldr sp, [r2, r4, lsl #2]
cmp r4, #0
bne _start_skip_bss_init_array
@ Clear bss section
ldr r0, =__bss_start__
ldr r1, =__bss_end__
sub r2, r1, r0
mov r1, #0
blx clear32
@ Setup newlib heap
ldr r0, =A11_HEAP_END
ldr r1, =fake_heap_end
str r0, [r1]
blx __libc_init_array @ Initialize ctors and dtors
blx PDN_core123Init
_start_skip_bss_init_array:
@ Disable + reset all performance monitor counters. Acknowledge IRQs.
ldrh r2, =PM_CCNT_IRQ | PM_PMN1_IRQ | PM_PMN0_IRQ | PM_CCNT_RST | PM_PMN01_RST
mcr p15, 0, r2, c15, c12, 0 @ Write Performance Monitor Control Register
blx setupMmu
bl mapDspRam
bl setupVfp
cpsie a
blx __systemInit
mov r0, #0 @ argc
adr r1, _dummyArgv @ argv
blx main
blx __systemDeinit
_start_lp:
wfi
b _start_lp
.pool
_sysmode_stacks:
.4byte A11_C0_STACK_END @ Stack for core 0
.4byte A11_C1_STACK_END @ Stack for core 1
.4byte A11_C2_STACK_END @ Stack for core 2
.4byte A11_C3_STACK_END @ Stack for core 3
_dummyArgv:
.4byte 0
END_ASM_FUNC
#define MAKE_BRANCH(src, dst) (0xEA000000 | (((((dst) - (src)) >> 2) - 2) & 0xFFFFFF))
BEGIN_ASM_FUNC stubExceptionVectors no_section
ldr r0, =A11_VECTORS_START
ldr r2, =MAKE_BRANCH(0, 0) @ Endless loop
mov r1, #6
stubExceptionVectors_lp:
str r2, [r0], #8
subs r1, r1, #1
bne stubExceptionVectors_lp
bx lr
.pool
END_ASM_FUNC
BEGIN_ASM_FUNC setupVfp no_section
mov r0, #0xF00000 @ Give full access to cp10/11 in user and privileged mode
mov r1, #0
mcr p15, 0, r0, c1, c0, 2 @ Write Coprocessor Access Control Register
mcr p15, 0, r1, c7, c5, 4 @ Flush Prefetch Buffer
mov r0, #0x40000000 @ Clear exception bits and enable VFP11
mov r1, #0x3000000 @ Round to nearest (RN) mode, flush-to-zero mode, default NaN mode
fmxr fpexc, r0 @ Write Floating-point exception register
fmxr fpscr, r1 @ Write Floating-Point Status and Control Register
bx lr
END_ASM_FUNC
BEGIN_ASM_FUNC mapDspRam no_section
ldr r2, =0x10140000
ldrd r0, r1, mapDspRam_cnt_val
strd r0, r1, [r2] @ REG_DSP_RAM_CODE_CNT.
strd r0, r1, [r2, #8] @ REG_DSP_RAM_DATA_CNT.
bx lr
.pool
.align 3
mapDspRam_cnt_val:
.8byte 0x9C9894908C888480 @ Map all of DSP RAM contiguous with the ARM CPUs as master.
END_ASM_FUNC
BEGIN_ASM_FUNC _init no_section thumb
bx lr
END_ASM_FUNC
BEGIN_ASM_FUNC deinitCpu no_section
mov r3, lr
cpsid aif, #PSR_SYS_MODE
bl stubExceptionVectors
bl cleanDCache
ldr r1, =0xC03805 @ Disable MMU, D-Cache, Program flow prediction, I-Cache,
@ high exception vectors, Unaligned data access,
@ subpage AP bits disabled
mrc p15, 0, r0, c1, c0, 0 @ Read control register
bic r0, r0, r1
mcr p15, 0, r0, c1, c0, 0 @ Write control register
mrc p15, 0, r0, c1, c0, 1 @ Read Auxiliary Control Register
bic r0, r0, #0x6F @ Return stack, Dynamic branch prediction, Static branch prediction,
@ Instruction folding, SMP mode: the CPU is taking part in coherency
@ and L1 parity checking
mcr p15, 0, r0, c1, c0, 1 @ Write Auxiliary Control Register
mcr p15, 0, r2, c7, c7, 0 @ Invalidate Both Caches. Also flushes the branch target cache
mcr p15, 0, r2, c7, c10, 4 @ Data Synchronization Barrier
mcr p15, 0, r2, c7, c5, 4 @ Flush Prefetch Buffer
bx r3
.pool
END_ASM_FUNC