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/*
* File : start_gcc.S
* This file is part of RT-Thread RTOS
* COPYRIGHT (C) 2013-2018, RT-Thread Development Team
*/
.equ MODE_USR, 0x10
.equ MODE_FIQ, 0x11
.equ MODE_IRQ, 0x12
.equ MODE_SVC, 0x13
.equ MODE_ABT, 0x17
.equ MODE_UND, 0x1B
.equ MODE_SYS, 0x1F
.equ MODEMASK, 0x1F
.equ NOINT, 0xC0
.equ I_BIT, 0x80
.equ F_BIT, 0x40
.equ UND_STACK_SIZE, 0x00000100
.equ SVC_STACK_SIZE, 0x00000100
.equ ABT_STACK_SIZE, 0x00000100
.equ FIQ_STACK_SIZE, 0x00000100
.equ IRQ_STACK_SIZE, 0x00000100
.equ SYS_STACK_SIZE, 0x00000100
/*
***************************************
* Interrupt vector table
***************************************
*/
.section .vectors
.code 32
.global system_vectors
system_vectors:
ldr pc, _vector_reset
ldr pc, _vector_undef
ldr pc, _vector_swi
ldr pc, _vector_pabt
ldr pc, _vector_dabt
ldr pc, _vector_resv
ldr pc, _vector_irq
ldr pc, _vector_fiq
_vector_reset:
.word reset
_vector_undef:
.word vector_undef
_vector_swi:
.word SVC_Handler
_vector_pabt:
.word vector_pabt
_vector_dabt:
.word vector_dabt
_vector_resv:
.word vector_resv
_vector_irq:
.word vector_irq
_vector_fiq:
.word vector_fiq
.balignl 16,0xdeadbeef
/*
***************************************
* Stack and Heap Definitions
***************************************
*/
.section .data
.space UND_STACK_SIZE
.align 3
.global und_stack_start
und_stack_start:
.space ABT_STACK_SIZE
.align 3
.global abt_stack_start
abt_stack_start:
.space FIQ_STACK_SIZE
.align 3
.global fiq_stack_start
fiq_stack_start:
.space IRQ_STACK_SIZE
.align 3
.global irq_stack_start
irq_stack_start:
.skip SYS_STACK_SIZE
.align 3
.global sys_stack_start
sys_stack_start:
.space SVC_STACK_SIZE
.align 3
.global svc_stack_start
svc_stack_start:
/*
***************************************
* Startup Code
***************************************
*/
.section .text
.global reset
reset:
/* Enter svc mode and mask interrupts */
mrs r0, cpsr
bic r0, r0, #MODEMASK
orr r0, r0, #MODE_SVC|NOINT
msr cpsr_cxsf, r0
/* init cpu */
bl cpu_init_crit
/* todo:copyself to link address */
/* Copy vector to the correct address */
ldr r0, =system_vectors
mrc p15, 0, r2, c1, c0, 0
ands r2, r2, #(1 << 13)
ldreq r1, =0x00000000
ldrne r1, =0xffff0000
ldmia r0!, {r2-r8, r10}
stmia r1!, {r2-r8, r10}
ldmia r0!, {r2-r8, r10}
stmia r1!, {r2-r8, r10}
/* turn off the watchdog */
ldr r0, =0x01C20CB8
mov r1, #0x0
str r1, [r0]
/* mask all IRQs source */
ldr r1, =0xffffffff
ldr r0, =0x01C20430
str r1, [r0], #0x04
str r1, [r0]
/* Call low level init function */
ldr sp, =svc_stack_start
ldr r0, =rt_low_level_init
blx r0
/* init stack */
bl stack_setup
/* clear bss */
mov r0, #0
ldr r1, =__bss_start
ldr r2, =__bss_end
bss_clear_loop:
cmp r1, r2
strlo r0, [r1], #4
blo bss_clear_loop
/* call c++ constructors of global objects */
/*
ldr r0, =__ctors_start__
ldr r1, =__ctors_end__
ctor_loop:
cmp r0, r1
beq ctor_end
ldr r2, [r0], #4
stmfd sp!, {r0-r1}
mov lr, pc
bx r2
ldmfd sp!, {r0-r1}
b ctor_loop
ctor_end:
*/
/* start RT-Thread Kernel */
ldr pc, _rtthread_startup
_rtthread_startup:
.word rtthread_startup
cpu_init_crit:
/* invalidate I/D caches */
mov r0, #0
mcr p15, 0, r0, c7, c7, 0
mcr p15, 0, r0, c8, c7, 0
/* disable MMU stuff and caches */
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #0x00002300
bic r0, r0, #0x00000087
orr r0, r0, #0x00000002
orr r0, r0, #0x00001000
mcr p15, 0, r0, c1, c0, 0
bx lr
stack_setup:
/* Setup Stack for each mode */
mrs r0, cpsr
bic r0, r0, #MODEMASK
orr r1, r0, #MODE_UND|NOINT
msr cpsr_cxsf, r1
ldr sp, =und_stack_start
orr r1, r0, #MODE_ABT|NOINT
msr cpsr_cxsf, r1
ldr sp, =abt_stack_start
orr r1, r0, #MODE_IRQ|NOINT
msr cpsr_cxsf, r1
ldr sp, =irq_stack_start
orr r1, r0, #MODE_FIQ|NOINT
msr cpsr_cxsf, r1
ldr sp, =fiq_stack_start
orr r1, r0, #MODE_SYS|NOINT
msr cpsr_cxsf,r1
ldr sp, =sys_stack_start
orr r1, r0, #MODE_SVC|NOINT
msr cpsr_cxsf, r1
ldr sp, =svc_stack_start
bx lr
/*
***************************************
* exception handlers
***************************************
*/
.global rt_hw_trap_udef
.global rt_hw_trap_swi
.global rt_hw_trap_pabt
.global rt_hw_trap_dabt
.global rt_hw_trap_resv
.global rt_hw_trap_irq
.global rt_hw_trap_fiq
.global rt_interrupt_enter
.global rt_interrupt_leave
.global rt_thread_switch_interrupt_flag
.global rt_interrupt_from_thread
.global rt_interrupt_to_thread
/* Interrupt */
.align 5
vector_fiq:
stmfd sp!,{r0-r7,lr}
bl rt_hw_trap_fiq
ldmfd sp!,{r0-r7,lr}
subs pc, lr, #4
.align 5
vector_irq:
stmfd sp!, {r0-r12,lr}
bl rt_interrupt_enter
bl rt_hw_trap_irq
bl rt_interrupt_leave
ldr r0, =rt_thread_switch_interrupt_flag
ldr r1, [r0]
cmp r1, #1
beq rt_hw_context_switch_interrupt_do
ldmfd sp!, {r0-r12,lr}
subs pc, lr, #4
rt_hw_context_switch_interrupt_do:
mov r1, #0
str r1, [r0]
mov r1, sp
add sp, sp, #4*4
ldmfd sp!, {r4-r12,lr}
mrs r0, spsr
sub r2, lr, #4
msr cpsr_c, #I_BIT|F_BIT|MODE_SVC
stmfd sp!, {r2}
stmfd sp!, {r4-r12,lr}
ldmfd r1, {r1-r4}
stmfd sp!, {r1-r4}
stmfd sp!, {r0}
ldr r4, =rt_interrupt_from_thread
ldr r5, [r4]
str sp, [r5]
ldr r6, =rt_interrupt_to_thread
ldr r6, [r6]
ldr sp, [r6]
ldmfd sp!, {r4}
msr spsr_cxsf, r4
ldmfd sp!, {r0-r12,lr,pc}^
/* Exception */
.macro push_svc_reg
sub sp, sp, #17 * 4
stmia sp, {r0 - r12}
mov r0, sp
mrs r6, spsr
str lr, [r0, #15*4]
str r6, [r0, #16*4]
str sp, [r0, #13*4]
str lr, [r0, #14*4]
.endm
.align 5
.weak SVC_Handler
SVC_Handler:
vector_swi:
push_svc_reg
bl rt_hw_trap_swi
b .
.align 5
vector_undef:
push_svc_reg
bl rt_hw_trap_udef
b .
.align 5
vector_pabt:
push_svc_reg
bl rt_hw_trap_pabt
b .
.align 5
vector_dabt:
push_svc_reg
bl rt_hw_trap_dabt
b .
.align 5
vector_resv:
push_svc_reg
bl rt_hw_trap_resv
b .
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