rt_system_scheduler_start()函数exception

发布于 2020-09-10 10:53:01 浏览：1468 订阅该版

经单步，发现在如下函数：（rvds.s文件中）

```
;/*
; * void rt_hw_context_switch_to(rt_uint32 to);
; * r0 --> to
; * this fucntion is used to perform the first thread switch
; */
rt_hw_context_switch_to    PROC
    EXPORT rt_hw_context_switch_to
    ; set to thread
    LDR     r1, =rt_interrupt_to_thread
    STR     r0, [r1]

; set from thread to 0
    LDR     r1, =rt_interrupt_from_thread
    MOVS    r0, #0x0
    STR     r0, [r1]

; set interrupt flag to 1
    LDR     r1, =rt_thread_switch_interrupt_flag
    MOVS    r0, #1
    STR     r0, [r1]

; set the PendSV exception priority
    LDR     r0, =NVIC_SHPR3
    LDR     r1, =NVIC_PENDSV_PRI
    LDR     r2, [r0,#0x00]       ; read
    ORRS    r1,r1,r2             ; modify
    STR     r1, [r0]             ; write-back

; trigger the PendSV exception (causes context switch)
    LDR     r0, =NVIC_INT_CTRL
    LDR     r1, =NVIC_PENDSVSET
    STR     r1, [r0]

; restore MSP
    LDR     r0, =SCB_VTOR
    LDR     r0, [r0]
    LDR     r0, [r0]
    MSR     msp, r0

; enable interrupts at processor level
    CPSIE   I		   ;faultful exception

; never reach here!
    ENDP
    
    
    CPSIE   I  这个执行会导致出现问题    rt_hw_hard_fault_exception
```

用的rtthread 版本椒3.13，在keil上模拟仿真。

谢谢