kernel/src/cpu/pic.c


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#include <io.h>
#include <pic.h>

void remap_pic(void)
{
	// starts the initialization sequence (in cascade mode)
	outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4);
	outb(PIC2_COMMAND, ICW1_INIT | ICW1_ICW4);
	outb(PIC1_DATA, 0xe0); // ICW2: Master PIC vector offset
	outb(PIC2_DATA, 0xe8); // ICW2: Slave PIC vector offset
	outb(PIC1_DATA,
	     4); // ICW3: tell Master PIC that there is a slave PIC at IRQ2 (0000 0100)
	outb(PIC2_DATA,
	     2); // ICW3: tell Slave PIC its cascade identity (0000 0010)

	outb(PIC1_DATA, ICW4_8086);
	outb(PIC2_DATA, ICW4_8086);

	// mask all interrupts
	outb(PIC1_DATA, 0xff);
	outb(PIC2_DATA, 0xff);
}