11buzzer_50000000.zip

#include "regs.h" #include "common.h" void do_irq(void) { void (*handler)(void) = NULL;//函数指针,函数的地址 if(VIC0ADDRESS)//这两个寄存器只能有一个非0 { handler = (void *)VIC0ADDRESS; } else if(VIC1ADDRESS) { handler = (void *)VIC1ADDRESS; } VIC0ADDRESS = 0; VIC1ADDRESS = 1; if(handler) { handler(); } handler = 0; } int irq_request(int num, void (*handler)(void))//用于设置enable和select以及对应的中断处理号(num)对应的中断处理函数(handler)地址放到相应的中断处理寄存器中 { if(num >= 0 && num <= 31) { VIC0INTENABLE |= 1 << num; VIC0INTSELECT &= ~(1 << num); VIC0VECTADDR[num] = (unsigned int)handler; } else if(num >= 32 && num <= 63) { num -= 31; VIC1INTENABLE |= 1 << num; VIC1INTSELECT &= ~(1 << num); VIC1VECTADDR[num] = (unsigned int)handler; } else { return -1; } __asm__ __volatile__( "mrs r0,cpsr\n" //读cpsr的值 //"and r0,r0,#0xffffff7f\n" //修改,将cpsr第7位置0 ，其他位不变 "bic r0,r0,#0x80\n" //修改，将cpsr第7位置为0 "msr cpsr,r0\n" //写入修改后的cpsr的值 ); return 0; }