at91.c

来自「基于ARM7微控制器AT91X40开发板的定时器程序」· C语言 代码 · 共 46 行

/*
 * at91.c
 * 
 * author: Kexin ([e-mail]) Tel:[phone]
 * date:   2007-11-22	
 */
#include "at91.h"
#include "at91_aic.h"
#include "at91_timer.h"

extern unsigned long svr[32];

void at91_install_irqhandler(void *isr)
{
  unsigned int *irq_vec_addr = (unsigned int*)0x18;
  unsigned int *isr_entry_addr = (unsigned int*)0x38;
  unsigned int instruction;

  *isr_entry_addr=(unsigned int)isr;
  instruction=((unsigned int)isr_entry_addr-(unsigned int)irq_vec_addr-0x08)|0xe59ff000;
  *irq_vec_addr = instruction;
}

void do_irq(void)
{
  unsigned int irq_num=0;
  void (*isr)(void);
 
label_again:
  irq_num=*(volatile unsigned int  *)AIC_IVR;
  if(irq_num!=0)
  {
    at91_mask_irq(irq_num);
    isr=(void*)svr[irq_num];
    if(isr!=0) isr();
    at91_unmask_irq(irq_num);
    *(volatile unsigned int  *)AIC_EOICR=irq_num;
    goto label_again;
   }
}

void at91_init(void *isr)
{
	at91_install_irqhandler(isr);
	at91_init_aic();
}