系统时钟为 80MHz配置 tx_thread_sleep 延时为 1ms
.global _tx_thread_system_stack_ptr
.global _tx_initialize_unused_memory
.global __RAM_segment_used_end__
.global _tx_timer_interrupt
.global __main
.global __tx_SVCallHandler
.global __tx_PendSVHandler
.global g_pfnVectors
.global __tx_NMIHandler @ NMI
.global __tx_BadHandler @ HardFault
.global __tx_SVCallHandler @ SVCall
.global __tx_DBGHandler @ Monitor
.global __tx_PendSVHandler @ PendSV
.global __tx_SysTickHandler @ SysTick
.global __tx_IntHandler @ Int 0
SYSTEM_CLOCK = 80000000 @ 系统时钟
TX_TICK_PER_SECOND = 1000 @ 1s 的时钟数
SYSTICK_CYCLES = ((SYSTEM_CLOCK / TX_TICK_PER_SECOND) -1) @滴答定时器 reload 值
.text 32
.align 4
.syntax unified
@VOID _tx_initialize_low_level(VOID)
@{
.global _tx_initialize_low_level
.thumb_func
_tx_initialize_low_level:
@ 关闭全局中断
CPSID i
@ _tx_initialize_unused_memory = __RAM_segment_used_end__ + 4
@ 设置未使用的 RAM 指针
LDR r0, =_tx_initialize_unused_memory @ Build address of unused memory pointer
LDR r1, =__RAM_segment_used_end__ @ Build first free address
ADD r1, r1, #4 @
STR r1, [r0] @ Setup first unused memory pointer
@ 设置中断向量表的偏移 SCB->VTOR = g_pfnVectors g_pfnVectors 为程序的起始地址：0x08000000
MOV r0, #0xE000E000 @ Build address of NVIC registers
LDR r1, =g_pfnVectors @ Pickup address of vector table
STR r1, [r0, #0xD08] @ Set vector table address
@ _tx_thread_system_stack_ptr = g_pfnVectors
LDR r0, =_tx_thread_system_stack_ptr @ Build address of system stack pointer
LDR r1, =g_pfnVectors @ Pickup address of vector table
LDR r1, [r1] @ Pickup reset stack pointer
STR r1, [r0] @ Save system stack pointer
@ DWT->CTRL 寄存器 CYCCNTENA 位置 1
LDR r0, =0xE0001000 @ Build address of DWT register
LDR r1, [r0] @ Pickup the current value
ORR r1, r1, #1 @ Set the CYCCNTENA bit
STR r1, [r0] @ Enable the cycle count register
@ SysTick->LOAD = SYSTICK_CYCLES 设置滴答定时器
MOV r0, #0xE000E000 @ Build address of NVIC registers
LDR r1, =SYSTICK_CYCLES
STR r1, [r0, #0x14] @ Setup SysTick Reload Value
@ SysTick->CTRL 的 0 1 2 三个位置 1 使能滴答定时器
MOV r1, #0x7 @ Build SysTick Control Enable Value
STR r1, [r0, #0x10] @ Setup SysTick Control
@ 设置中断优先级
LDR r1, =0x00000000 @ Rsrv, UsgF, BusF, MemM
STR r1, [r0, #0xD18] @ Setup System Handlers 4-7 Priority Registers
LDR r1, =0xFF000000 @ SVCl, Rsrv, Rsrv, Rsrv
STR r1, [r0, #0xD1C] @ Setup System Handlers 8-11 Priority Registers
@ Note: SVC must be lowest priority, which is 0xFF
LDR r1, =0x40FF0000 @ SysT, PnSV, Rsrv, DbgM
STR r1, [r0, #0xD20] @ Setup System Handlers 12-15 Priority Registers
@ Note: PnSV must be lowest priority, which is 0xFF
@
@ /* Return to caller. */
@
BX lr
@}
@
@/* Define shells for each of the unused vectors. */
@
.global __tx_BadHandler
.thumb_func
__tx_BadHandler:
B __tx_BadHandler
@ /* added to catch the hardfault */
.global __tx_HardfaultHandler
.thumb_func
__tx_HardfaultHandler:
B __tx_HardfaultHandler
@ /* added to catch the SVC */
.global __tx_SVCallHandler
.thumb_func
__tx_SVCallHandler:
B __tx_SVCallHandler
@ /* Generic interrupt handler template */
.global __tx_IntHandler
.thumb_func
__tx_IntHandler:
@ VOID InterruptHandler (VOID)
@ {
PUSH {r0, lr}
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
BL _tx_execution_isr_enter @ Call the ISR enter function
#endif
@ /* Do interrupt handler work here */
@ /* BL <your C Function>.... */
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
BL _tx_execution_isr_exit @ Call the ISR exit function
#endif
POP {r0, lr}
BX LR
@ }
@ /* System Tick timer interrupt handler */
.global __tx_SysTickHandler
.global SysTick_Handler
.thumb_func
__tx_SysTickHandler:
.thumb_func
@ 滴答定时器的中断服务函数
SysTick_Handler:
@ VOID TimerInterruptHandler (VOID)
@ {
@
PUSH {r0, lr}
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
BL _tx_execution_isr_enter @ Call the ISR enter function
#endif
BL _tx_timer_interrupt
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
BL _tx_execution_isr_exit @ Call the ISR exit function
#endif
POP {r0, lr}
BX LR
@ }
@ /* NMI, DBG handlers */
.global __tx_NMIHandler
.thumb_func
__tx_NMIHandler:
B __tx_NMIHandler
.global __tx_DBGHandler
.thumb_func
__tx_DBGHandler:
B __tx_DBGHandler
