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#include "idt.h"
#include <stdint.h>
struct __attribute__((packed)) Pointer {
uint16_t limit;
uint32_t base;
};
enum Type {
Null = 0,
Intr = 0x8e /* 1000 1110 32-bit interrupt */
};
struct __attribute__((packed)) Gate_t {
uint16_t offset_15_0; /* segment offset low */
uint16_t selector; /* code segment selector */
uint8_t __unused; /* unused in protected mode */
uint8_t type; /* interrupt type */
uint16_t offset_31_16; /* segment offset high */
};
/* _Static_assert(sizeof(struct Gate_t) == 8, "interrupt gate size"); */
void
Gate(struct Gate_t *entry, void (*f)(struct interrupt_frame *), uint16_t selector)
{
uint32_t f_addr = (uint32_t)f;
entry->offset_15_0 = f_addr & 0xffff;
entry->offset_31_16 = (uint16_t)(f_addr >> 16) & 0xffff;
entry->selector = selector;
entry->__unused = 0;
entry->type = Intr;
}
static struct Gate_t interrupt_table[256] __attribute((aligned(4096)));
void
idt_install()
{
int i;
const struct Pointer ptr = {sizeof(interrupt_table) - 1, (unsigned)&interrupt_table};
/* exceptions 0x00~0x13 */
for (i = 0; i <= 0x13; ++i) Gate(&interrupt_table[i], &abort_handler, 0x10);
/* irq 0x20~0x2f */
for (i = 0x22; i <= 0x2f; ++i) Gate(&interrupt_table[i], &abort_handler, 0x10);
Gate(&interrupt_table[0x20], &irq0x00, 0x10);
Gate(&interrupt_table[0x21], &irq0x01, 0x10);
Gate(&interrupt_table[0x2c], &irq0x0c, 0x10);
/* syscall 0x80 */
Gate(&interrupt_table[0x80], &syscall_handler, 0x10);
__asm__("lidt (%0)" : : "a"(&ptr));
}
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