rt-thread/bsp/dm365/platform/start_gcc.S

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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
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*
* SPDX-License-Identifier: Apache-2.0
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*
* Change Logs:
* Date Author Notes
* 2010-11-13 weety first version
*/
#define CONFIG_STACKSIZE 512
#define S_FRAME_SIZE 68
#define S_PC 64
#define S_LR 60
#define S_SP 56
#define S_IP 52
#define S_FP 48
#define S_R10 44
#define S_R9 40
#define S_R8 36
#define S_R7 32
#define S_R6 28
#define S_R5 24
#define S_R4 20
#define S_R3 16
#define S_R2 12
#define S_R1 8
#define S_R0 4
#define S_CPSR 0
.equ I_BIT, 0x80 @ when I bit is set, IRQ is disabled
.equ F_BIT, 0x40 @ when F bit is set, FIQ is disabled
.equ USERMODE, 0x10
.equ FIQMODE, 0x11
.equ IRQMODE, 0x12
.equ SVCMODE, 0x13
.equ ABORTMODE, 0x17
.equ UNDEFMODE, 0x1b
.equ MODEMASK, 0x1f
.equ NOINT, 0xc0
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.equ RAM_BASE, 0x00000000 /*Start address of RAM */
.equ ROM_BASE, 0x80000000 /*Start address of Flash */
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.equ EINT_ENABLE0, 0x01c48018
.equ EINT_ENABLE1, 0x01c4801c
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/*
*************************************************************************
*
* Jump vector table
*
*************************************************************************
*/
.section .init, "ax"
.code 32
.globl _start
_start:
b 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_undef: .word vector_undef
_vector_swi: .word vector_swi
_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
/*
*************************************************************************
*
* Startup Code (reset vector)
* relocate armboot to ram
* setup stack
* jump to second stage
*
*************************************************************************
*/
_TEXT_BASE:
.word TEXT_BASE
/*
* rtthread kernel start and end
* which are defined in linker script
*/
.globl _rtthread_start
_rtthread_start:
.word _start
.globl _rtthread_end
_rtthread_end:
.word _end
/*
* rtthread bss start and end which are defined in linker script
*/
.globl _bss_start
_bss_start:
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.word __bss_start
.globl _bss_end
_bss_end:
.word __bss_end
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
.word _irq_stack_start + 1024
.globl FIQ_STACK_START
FIQ_STACK_START:
.word _fiq_stack_start + 1024
.globl UNDEFINED_STACK_START
UNDEFINED_STACK_START:
.word _undefined_stack_start + CONFIG_STACKSIZE
.globl ABORT_STACK_START
ABORT_STACK_START:
.word _abort_stack_start + CONFIG_STACKSIZE
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.globl _STACK_START
_STACK_START:
.word _svc_stack_start + 1024
/* ----------------------------------entry------------------------------*/
reset:
/* set the cpu to SVC32 mode */
mrs r0,cpsr
bic r0,r0,#MODEMASK
orr r0,r0,#SVCMODE
msr cpsr,r0
/* mask all IRQs by clearing all bits in the INTMRs */
mov r1, $0
ldr r0, =EINT_ENABLE0
str r1, [r0]
ldr r0, =EINT_ENABLE1
str r1, [r0]
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#if 0
/* set interrupt vector */
ldr r0, _TEXT_BASE
mov r1, #0x00
add r2, r0, #0x40 /* size, 32bytes */
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copy_loop:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
stmia r1!, {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end addreee [r2] */
ble copy_loop
#endif
/* setup stack */
bl stack_setup
/* clear .bss */
mov r0,#0 /* get a zero */
ldr r1,=__bss_start /* bss start */
ldr r2,=__bss_end /* bss end */
bss_loop:
cmp r1,r2 /* check if data to clear */
strlo r0,[r1],#4 /* clear 4 bytes */
blo bss_loop /* loop until done */
/* 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:
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.word rtthread_startup
#if defined (__FLASH_BUILD__)
_load_address:
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.word ROM_BASE + _TEXT_BASE
#else
_load_address:
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.word RAM_BASE + _TEXT_BASE
#endif
/*
*************************************************************************
*
* Interrupt handling
*
*************************************************************************
*/
.macro push_exp_reg
sub sp, sp, #S_FRAME_SIZE @/* Sizeof(struct rt_hw_stack) */
stmib sp, {r0 - r12} @/* Calling r0-r12 */
mov r0, sp
mrs r6, spsr @/* Save CPSR */
str lr, [r0, #S_PC] @/* Push PC */
str r6, [r0, #S_CPSR] @/* Push CPSR */
@ switch to SVC mode with no interrupt
msr cpsr_c, #I_BIT|F_BIT|SVCMODE
str sp, [r0, #S_SP] @/* Save calling SP */
str lr, [r0, #S_LR] @/* Save calling PC */
.endm
/* exception handlers */
.align 5
vector_undef:
push_exp_reg
bl rt_hw_trap_udef
.align 5
vector_swi:
push_exp_reg
bl rt_hw_trap_swi
.align 5
vector_pabt:
push_exp_reg
bl rt_hw_trap_pabt
.align 5
vector_dabt:
push_exp_reg
bl rt_hw_trap_dabt
.align 5
vector_resv:
push_exp_reg
bl rt_hw_trap_resv
.globl rt_interrupt_enter
.globl rt_interrupt_leave
.globl rt_thread_switch_interrupt_flag
.globl rt_interrupt_from_thread
.globl rt_interrupt_to_thread
vector_irq:
stmfd sp!, {r0-r12,lr}
bl rt_interrupt_enter
bl rt_hw_trap_irq
bl rt_interrupt_leave
@ if rt_thread_switch_interrupt_flag set, jump to
@ rt_hw_context_switch_interrupt_do and don't return
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
.align 5
vector_fiq:
stmfd sp!,{r0-r7,lr}
bl rt_hw_trap_fiq
ldmfd sp!,{r0-r7,lr}
subs pc,lr,#4
rt_hw_context_switch_interrupt_do:
mov r1, #0 @ clear flag
str r1, [r0]
ldmfd sp!, {r0-r12,lr}@ reload saved registers
stmfd sp, {r0-r2} @ save r0-r2
mrs r0, spsr @ get cpsr of interrupt thread
sub r1, sp, #4*3
sub r2, lr, #4 @ save old task's pc to r2
@ switch to SVC mode with no interrupt
msr cpsr_c, #I_BIT|F_BIT|SVCMODE
stmfd sp!, {r2} @ push old task's pc
stmfd sp!, {r3-r12,lr}@ push old task's lr,r12-r4
ldmfd r1, {r1-r3} @ restore r0-r2 of the interrupt thread
stmfd sp!, {r1-r3} @ push old task's r0-r2
stmfd sp!, {r0} @ push old task's cpsr
ldr r4, =rt_interrupt_from_thread
ldr r5, [r4]
str sp, [r5] @ store sp in preempted tasks's TCB
ldr r6, =rt_interrupt_to_thread
ldr r6, [r6]
ldr sp, [r6] @ get new task's stack pointer
ldmfd sp!, {r4} @ pop new task's cpsr to spsr
msr spsr_cxsf, r4
ldmfd sp!, {r0-r12,lr,pc}^ @ pop new task's r0-r12,lr & pc, copy spsr to cpsr
stack_setup:
mrs r0, cpsr
bic r0, r0, #MODEMASK
orr r1, r0, #UNDEFMODE|NOINT
msr cpsr_cxsf, r1 /* undef mode */
ldr sp, UNDEFINED_STACK_START
orr r1,r0,#ABORTMODE|NOINT
msr cpsr_cxsf,r1 /* abort mode */
ldr sp, ABORT_STACK_START
orr r1,r0,#IRQMODE|NOINT
msr cpsr_cxsf,r1 /* IRQ mode */
ldr sp, IRQ_STACK_START
orr r1,r0,#FIQMODE|NOINT
msr cpsr_cxsf,r1 /* FIQ mode */
ldr sp, FIQ_STACK_START
bic r0,r0,#MODEMASK
orr r1,r0,#SVCMODE|NOINT
msr cpsr_cxsf,r1 /* SVC mode */
ldr sp, _STACK_START
/* USER mode is not initialized. */
bx lr /* The LR register may be not valid for the mode changes.*/
/*/*}*/