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// MIT License, Copyright (c) 2021 Marvin Borner
#include <cpu.h>
#include <pic.h>
#define PIC1 0x20
#define PIC1_COMMAND PIC1
#define PIC1_OFFSET 0x20
#define PIC1_DATA (PIC1 + 1)
#define PIC2 0xa0
#define PIC2_COMMAND PIC2
#define PIC2_OFFSET 0x28
#define PIC2_DATA (PIC2 + 1)
#define ICW1_ICW4 0x01
#define ICW1_INIT 0x10
static void pic_wait(void)
{
__asm__ volatile("jmp 1f\n\t"
"1:\n\t"
" jmp 2f\n\t"
"2:");
}
void pic_install(void)
{
// Initialize
outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4);
pic_wait();
outb(PIC2_COMMAND, ICW1_INIT | ICW1_ICW4);
pic_wait();
// Remap
outb(PIC1_DATA, PIC1_OFFSET);
pic_wait();
outb(PIC2_DATA, PIC2_OFFSET);
pic_wait();
outb(PIC1_DATA, 0x04);
pic_wait();
outb(PIC2_DATA, 0x02);
pic_wait();
// Set 8086 mode
outb(PIC1_DATA, 0x01);
pic_wait();
outb(PIC2_DATA, 0x01);
pic_wait();
outb(PIC1_DATA, 0x00);
pic_wait();
outb(PIC2_DATA, 0x00);
pic_wait();
}
void pic_ack(u32 interrupt_no)
{
if (interrupt_no >= 40)
outb(PIC2, 0x20);
outb(PIC1, 0x20);
}
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