61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
#include <stdint.h>
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#include <idt.h>
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#define IDT_MAX_DESCRIPTORS 256
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#define ATTR_KERN_32 0x8E // active(1), ring 0 (00), interrupt gate(0), 32 bit (1110)
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#define ATTR_USER_32 0xEE // active, ring 3, 32bit
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#define SEGMENT_KERN 0x08
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extern void load_idt(void);
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extern void enable_int(void);
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extern void isr0();
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extern void isr1();
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extern void isr8();
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extern void isr13();
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extern void isr14();
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extern void isr32();
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extern void isr33();
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void* isr_stub_table[256] = {
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[0] = isr0,
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[1] = isr1,
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[8] = isr8,
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[13] = isr13,
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[14] = isr14,
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[32] = isr32,
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[33] = isr33,
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};
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idt_entry idt[IDT_MAX_DESCRIPTORS];
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idt_ptr idtr;
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void set_idtr(uint8_t vector, void* isr, uint16_t sel, uint8_t attributes) {
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idt_entry* desc = &idt[vector];
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desc->isr_low = (uint32_t)isr & 0xFFFF;
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desc->selector = SEGMENT_KERN;
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desc->reserved = 0;
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desc->attributes = attributes;
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desc->isr_high = ((uint32_t)isr >> 16) & 0xFFFF;
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}
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void init_idt() {
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idtr.limit = (sizeof(idt_entry) * IDT_MAX_DESCRIPTORS) - 1;
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idtr.base = (uint32_t)&idt;
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for (int i = 0; i < IDT_MAX_DESCRIPTORS; i++) {
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if (isr_stub_table[i] != 0) {
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set_idtr(i, isr_stub_table[i], SEGMENT_KERN, ATTR_KERN_32);
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} else {
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set_idtr(i, 0, SEGMENT_KERN, 0);
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}
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}
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extern void syscall_handler();
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set_idtr(0x80, syscall_handler, SEGMENT_KERN, ATTR_USER_32);
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load_idt();
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} |