i8259.c

这是《自己动手写操作系统》的原文件和代码

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                            i8259.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                                                    Forrest Yu, 2005
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/


#include "type.h"
#include "const.h"
#include "protect.h"
#include "proto.h"


/*======================================================================*
                            init_8259A
 *======================================================================*/
PUBLIC void init_8259A()
{
	out_byte(INT_M_CTL,	0x11);			// Master 8259, ICW1.
	out_byte(INT_S_CTL,	0x11);			// Slave  8259, ICW1.
	out_byte(INT_M_CTLMASK,	INT_VECTOR_IRQ0);	// Master 8259, ICW2. 设置 '主8259' 的中断入口地址为 0x20.
	out_byte(INT_S_CTLMASK,	INT_VECTOR_IRQ8);	// Slave  8259, ICW2. 设置 '从8259' 的中断入口地址为 0x28
	out_byte(INT_M_CTLMASK,	0x4);			// Master 8259, ICW3. IR2 对应 '从8259'.
	out_byte(INT_S_CTLMASK,	0x2);			// Slave  8259, ICW3. 对应 '主8259' 的 IR2.
	out_byte(INT_M_CTLMASK,	0x1);			// Master 8259, ICW4.
	out_byte(INT_S_CTLMASK,	0x1);			// Slave  8259, ICW4.

	out_byte(INT_M_CTLMASK,	0xFD);	// Master 8259, OCW1. 
	out_byte(INT_S_CTLMASK,	0xFF);	// Slave  8259, OCW1. 
}

/*======================================================================*
                           spurious_irq
 *======================================================================*/
PUBLIC void spurious_irq(int irq)
{
	disp_str("spurious_irq: ");
	disp_int(irq);
	disp_str("\n");
}