请教W90P710 IRQ中断的问题

只看该作者 · 2010-8-12 20:09

下面是我写的IRQ_Handler程序。

      EXPORT IRQ_Handler
IMPORT Fake_Interrupt ,WEAK
IMPORT Int1_Interrupt ,WEAK
IMPORT Int2_Interrupt ,WEAK
IMPORT Int3_Interrupt ,WEAK
IMPORT Int4_Interrupt ,WEAK
IMPORT Int5_Interrupt ,WEAK
IMPORT Int6_Interrupt ,WEAK
IMPORT Int7_Interrupt ,WEAK
IMPORT Int8_Interrupt ,WEAK
IMPORT Int9_Interrupt ,WEAK
      IMPORT Int10_Interrupt ,WEAK
      IMPORT Int11_Interrupt ,WEAK
      IMPORT Int12_Interrupt ,WEAK
      IMPORT Int13_Interrupt ,WEAK
      IMPORT Int14_Interrupt ,WEAK
      IMPORT Int15_Interrupt ,WEAK
      IMPORT Int16_Interrupt ,WEAK
      IMPORT Int17_Interrupt ,WEAK
      IMPORT Int18_Interrupt ,WEAK
      IMPORT Int19_Interrupt ,WEAK
      IMPORT Int20_Interrupt ,WEAK
      IMPORT Int21_Interrupt ,WEAK
      IMPORT Int22_Interrupt ,WEAK
      IMPORT Int23_Interrupt ,WEAK
      IMPORT Int24_Interrupt ,WEAK
      IMPORT Int25_Interrupt ,WEAK
      IMPORT Int26_Interrupt ,WEAK
      IMPORT Int27_Interrupt ,WEAK
      IMPORT Int28_Interrupt ,WEAK
      IMPORT Int29_Interrupt ,WEAK
      IMPORT Int30_Interrupt ,WEAK
      IMPORT Int31_Interrupt ,WEAK

AIC_IPER EQU 0xFFF8210C

      AREA IRQ , CODE ,READONLY

IRQ_Handler
      SUB    LR, LR, #4
            STMFD SP!, {R0-R12, LR}
      MSR    CPSR_c, #0X9F                   ;// Switch to User module
      LDR R2, =AICBase

      LDR R3, =AIC_IPER
      LDR R3,[R3]
      LDR R1, [R2,R3] ; gets the highest pendingvector
      LDR PC, [PC, R1] ; jump to correct handler
      NOP
      ;table of handler start address
AICBase
            DCD Fake_Interrupt
      DCD Int1_Interrupt
      DCD Int2_Interrupt
      DCD Int3_Interrupt
      DCD Int4_Interrupt
      DCD Int5_Interrupt
      DCD Int6_Interrupt
      DCD Int7_Interrupt
      DCD Int8_Interrupt
      DCD Int9_Interrupt
      DCD Int10_Interrupt
      DCD Int11_Interrupt
      DCD Int12_Interrupt
      DCD Int13_Interrupt
      DCD Int14_Interrupt
      DCD Int15_Interrupt
      DCD Int16_Interrupt
      DCD Int17_Interrupt
      DCD Int18_Interrupt
      DCD Int19_Interrupt
      DCD Int20_Interrupt
      DCD Int21_Interrupt
      DCD Int22_Interrupt
      DCD Int23_Interrupt
      DCD Int24_Interrupt
      DCD Int25_Interrupt
      DCD Int26_Interrupt
      DCD Int27_Interrupt
      DCD Int28_Interrupt
      DCD Int29_Interrupt
      DCD Int30_Interrupt
      DCD Int31_Interrupt

      rAIC_EOSCR = 0;
      MSR    CPSR_c, #0X92             ;// Switch to IRQ module
      LDMFD SP!, {R0-R12, PC}^
END

这些是在IQR_Handler里面的，而Int1_Interrupt ~Int31_Interrupt是准备用C语言实现的中断函数。比如

void Int1_Interrupt(void)
{

}

请大家找出错误与不合理之处。万分感激

只看该作者 · 2010-8-12 20:10

问题是：
这样写是通过LDR PC, [PC, R1] 语句跳转到中断服务函数中的，但是如果中断服务函数运行完的话PC还会跳回到
LDR PC, [PC, R1] 后面的语句，也就是NOP 语句执行吗，这样写是不是不科学？

只看该作者 · 2010-8-12 20:44

肯定不科学呢，你在进去IRQ_Handler的时候不是保存了LR和cpsr了么，你出来的时候要恢复他们的值啊，中断是中断了一个正在运行的进程，但是当中断完成的时候，你得恢复这个进程继续执行，而不是进到一个nop里面啥也不做，系统不就挂掉了么。

请教W90P710 IRQ中断的问题

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