tabs/kernel/interrupts.c
2020-01-09 12:06:45 +01:00

80 lines
No EOL
1.8 KiB
C

#ifndef INTERRUPTS_C
#define INTERRUPTS_C
#include <stdint.h>
#include <stddef.h>
#include "memory.c"
#include "terminal.c"
#include "inline_asm.c"
#include "drivers/keyboard/keyboard.c"
typedef struct idt_entry_struct {
uint16_t offset_1; // offset bits 0..15
uint16_t selector; // a code segment selector in GDT or LDT
uint8_t zero; // unused, set to 0
uint8_t type_attr; // type and attributes, see below
uint16_t offset_2; // offset bits 16..31
} idt_entry;
struct interrupt_frame {
uint32_t esp;
uint32_t ss;
uint32_t gs;
uint32_t fs;
uint32_t es;
uint32_t ds;
uint32_t ebp;
uint32_t edi;
uint32_t esi;
uint32_t edx;
uint32_t ecx;
uint32_t ebx;
uint32_t eax;
uint32_t eip;
uint32_t cs;
uint32_t eflags;
};
idt_entry IDT[256];
void interrupt_new_handler(int intnum, void (*handler)(struct interrupt_frame*)) {
uint32_t handler_address = (uint32_t) handler;
IDT[intnum].offset_1 = (uint16_t) (handler_address & 0xffff);
IDT[intnum].selector = 0x08;
IDT[intnum].zero = 0;
IDT[intnum].type_attr = 0b10001110; // Active, privilege level 00, storage segment = 0; 32 bit interrupt gate
IDT[intnum].offset_2 = (uint16_t) ((handler_address & 0xffff0000) >> 16);
}
void interrupt_init() {
/* ICW1 - begin initialization */
outb(0x20, 0x11);
outb(0xA0, 0x11);
/* ICW2 - remap offset address of IDT */
outb(0x21, 0x20);
outb(0xA1, 0x82);
/* ICW3 - setup cascading */
outb(0x21, 0x00);
outb(0xA1, 0x00);
/* ICW4 - environment info */
outb(0x21, 0x01);
outb(0xA1, 0x01);
/* mask interrupts */
outb(0x21 , 0xff);
outb(0xA1 , 0xff);
interrupt_new_handler(0x21, keyboard_handler);
uint16_t size = (sizeof(idt_entry) * 256);
lidt(IDT, size);
keyboard_init();
}
#endif //INTERRUPTS_C