Interrupt of ARM A7

.text
.align 2         //设置字节对齐
.global _start
_start:

    ldr     pc, =Reset_Handler           /* Reset                  */
    ldr     pc, =Undefined_Handler       /* Undefined instructions */
    ldr     pc, =SVC_Handler             /* Supervisor Call        */
    ldr     pc, =PrefAbort_Handler       /* Prefetch abort         */
    ldr     pc, =DataAbort_Handler       /* Data abort             */
    .word   0                            /* RESERVED               */
    ldr     pc, =IRQ_Handler             /* IRQ interrupt          */
    ldr     pc, =FIQ_Handler             /* FIQ interrupt          */



/**********************第三部分*********************/
Reset_Handler:
    cpsid   i                         /* 全局关闭中断 */


    mrc     p15, 0, r0, c1, c0, 0     /*读取CP15系统控制寄存器   */
    bic     r0,  r0, #(0x1 << 12)     /*  清除第12位（I位）禁用 I Cache  */
    bic     r0,  r0, #(0x1 <<  2)     /*  清除第 2位（C位）禁用 D Cache  */
    bic     r0,  r0, #0x2             /*  清除第 1位（A位）禁止严格对齐   */
    bic     r0,  r0, #(0x1 << 11)     /*  清除第11位（Z位）分支预测   */
    bic     r0,  r0, #0x1             /*  清除第 0位（M位）禁用 MMU   */
    mcr     p15, 0, r0, c1, c0, 0     /*  将修改后的值写回CP15寄存器   */

/**********************第四部分*********************/
    /* 定义IRQ工作模式的栈起始地址 */
    cps     #0x12
    ldr     sp, =IRQ_model_stack_start

    /*定义User工作模式的栈起始地址，与Supervisor相同*/
    cps     #0x1F
    ldr     sp, =SUP_model_stack_start

    /*定义Supervisor工作模式的栈起始地址，与User相同 */
    cps     #0x13
    ldr     sp, =SUP_model_stack_start

/**********************第五部分*******************/
    /*跳转到系统初始化函数，初始化GIC、CACHE-L1、mmu等等*/
    ldr     r2, =SystemInit
    blx     r2

 /*********************第六部分*******************/
    /*开启全局中断*/
    cpsie   i

    /*跳转到到 main 函数执行，*/
    b main
    b .        /*死循环*/
    /*其他中断处理函数与官方相同这里省略，可直接打开源码查看*/

void SystemInit(void)
{
  uint32_t sctlr;
  uint32_t actlr;
 #if ((__FPU_PRESENT == 1) && (__FPU_USED == 1))
  uint32_t cpacr;
  uint32_t fpexc;
 #endif

  L1C_InvalidateInstructionCacheAll();
  L1C_InvalidateDataCacheAll();

  actlr = __get_ACTLR();
  actlr = (actlr | ACTLR_SMP_Msk); /* Change to SMP mode before enable DCache */
  __set_ACTLR(actlr);

  sctlr = __get_SCTLR();
  sctlr = (sctlr & ~(SCTLR_V_Msk | /* Use low vector */
                     SCTLR_A_Msk | /* Disable alignment fault checking */
                     SCTLR_M_Msk)) /* Disable MMU */
          | (SCTLR_I_Msk |         /* Enable ICache */
             SCTLR_Z_Msk |         /* Enable Prediction */
             SCTLR_CP15BEN_Msk |   /* Enable CP15 barrier operations */
             SCTLR_C_Msk);         /* Enable DCache */
  __set_SCTLR(sctlr);

  /* Set vector base address */
  GIC_Init();
  __set_VBAR((uint32_t)__VECTOR_TABLE);

  // rgb_led_init();
  // blue_led_on;
 #if ((__FPU_PRESENT == 1) && (__FPU_USED == 1))
  cpacr = __get_CPACR();
  /* Enable NEON and FPU */
  cpacr = (cpacr & ~(CPACR_ASEDIS_Msk | CPACR_D32DIS_Msk)) | (3UL << CPACR_cp10_Pos) | (3UL << CPACR_cp11_Pos);
  __set_CPACR(cpacr);

  fpexc = __get_FPEXC();
  fpexc |= 0x40000000UL; /* Enable NEON and FPU */
  __set_FPEXC(fpexc);
 #endif /* ((__FPU_PRESENT == 1) && (__FPU_USED == 1)) */
}

void interrupt_button2_init(void)
{
    volatile uint32_t *icr;  //用于保存 GPIO-ICR寄存器的地址,与 icrShift 变量配合使用
    uint32_t icrShift;       //引脚号大于16时会用到,

    icrShift = button2_GPIO_PIN;  //保存button2引脚对应的 GPIO 号

    /*添加中断服务函数到  "中断向量表"*/
    SystemInstallIrqHandler(GPIO5_Combined_0_15_IRQn, (system_irq_handler_t)EXAMPLE_GPIO_IRQHandler, NULL);
    GIC_EnableIRQ(GPIO5_Combined_0_15_IRQn);                 //开启中断


    CCM_CCGR1_CG15(0x3);  //开启GPIO5的时钟

    /*设置 按键引脚的PAD属性*/
    IOMUXC_SetPinMux(IOMUXC_SNVS_SNVS_TAMPER1_GPIO5_IO01,0);     
    IOMUXC_SetPinConfig(IOMUXC_SNVS_SNVS_TAMPER1_GPIO5_IO01, button_PAD_CONFIG_DATA); 
    
    /*设置GPIO方向（输入或输出）*/
    GPIO5->IMR &= ~(1 << button2_GPIO_PIN);  //寄存器重置为默认值
    GPIO5->GDIR &= ~(1<<1);                  //设置GPIO5_01为输入模式

    /*设置GPIO引脚中断类型*/
    GPIO5->EDGE_SEL &= ~(1U << button2_GPIO_PIN);//寄存器重置为默认值

    if(button2_GPIO_PIN < 16)
    {
        icr = &(GPIO5->ICR1);       // interrupt configuration register1 save all interrupt trigger mode//
    }
    else
    {
        icr = &(GPIO5->ICR2);
        icrShift -= 16;
    }

    /*按键引脚默认低电平，设置为上升沿触发中断*/
     *icr = (*icr & (~(3U << (2 * icrShift)))) | (2U << (2 * icrShift));

     button2_GPIO->IMR |= (1 << button2_GPIO_PIN);    // IMR--interrupt mask register 1 for enable interrupt/
}

void SystemInstallIrqHandler(IRQn_Type irq, system_irq_handler_t handler, void *userParam)
{
  irqTable[irq].irqHandler = handler;
  irqTable[irq].userParam = userParam;
}

typedef struct _sys_irq_handle
{
    system_irq_handler_t irqHandler; /**< IRQ handler for specific IRQ */
    void *userParam;                 /**< User param for handler callback */
} sys_irq_handle_t;

static sys_irq_handle_t irqTable[NUMBER_OF_INT_VECTORS];

typedef void (*system_irq_handler_t) (uint32_t giccIar, void *param);

void EXAMPLE_GPIO_IRQHandler(void)
{
    /*按键引脚中断服务函数*/
    button2_GPIO->ISR = 1U << button2_GPIO_PIN;  //清除GIIP中断标志位
    if(button_status > 0)
    {
        button_status = 0;
    }
    else
    {
        button_status = 1;
    }
}

char (*pFun)(int);   
char glFun(int a){ return;}   
void main()   
{   
    pFun = glFun;   
    (*pFun)(2);   
}  

typedef char (*PTRFUN)(int);   
PTRFUN pFun;   
char glFun(int a){ return;}   
void main()   
{   
    pFun = glFun;   
    (*pFun)(2);   
}