ucos4skyeye中断安装函数有点不理解
void install_irqhandler(void * isr){
/* ARM irq exception vector addr is 0x00000018*/
unsigned int * irq_vec_addr = ( unsigned int * ) 0x18;
/* this is isr entry address, could be another address like 0x3c, 0x58... */
unsigned int * isr_entry_addr = ( unsigned int * ) 0x38;
unsigned int instruction;
/* set the ISR entry at 0x38*/
*isr_entry_addr = (unsigned int)isr;
/* make an instruction: it is machine-code for "ldrpc, "*/
/* pc是预取指令，会自动加8所以要得出中断处理函数地址的偏移量就后再减去pc事
先自动加上的8才得到真正的偏移量 */
instruction = ((unsigned int) isr_entry_addr- (unsigned int)irq_vec_addr - 0x0 | 0xe59ff000;
/* set this instruction at 0x18*/
*irq_vec_addr = instruction;
}
我的理解是当irq中断发生，从向量表0x18跳转到0x38去寻找中断处理函数。问题是0x38只是存放了isr的地址，没有使用ldr之类的指令pc指针怎么从0x38又跳转到isr的地址的呢？ :-D 看代码不仔细，结贴了
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