108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
#ifndef INTERRUPTS_C
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#define INTERRUPTS_C
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#include <stdint.h>
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#include <stddef.h>
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#include "memory.c"
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#include "terminal.c"
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#include "inline_asm.c"
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typedef struct idt_entry_struct {
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uint16_t offset_1; // offset bits 0..15
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uint16_t selector; // a code segment selector in GDT or LDT
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uint8_t zero; // unused, set to 0
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uint8_t type_attr; // type and attributes, see below
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uint16_t offset_2; // offset bits 16..31
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} idt_entry;
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struct interrupt_frame {
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uint32_t esp;
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uint32_t ss;
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uint32_t gs;
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uint32_t fs;
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uint32_t es;
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uint32_t ds;
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uint32_t ebp;
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uint32_t edi;
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uint32_t esi;
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uint32_t edx;
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uint32_t ecx;
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uint32_t ebx;
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uint32_t eax;
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uint32_t eip;
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uint32_t cs;
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uint32_t eflags;
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};
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idt_entry IDT[256];
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int count = 1;
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void interrupt_new_handler(int intnum, void (*handler)(struct interrupt_frame*)) {
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uint32_t handler_address = (uint32_t) handler;
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IDT[intnum].offset_1 = (uint16_t) (handler_address & 0xffff);
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IDT[intnum].selector = 0x08;
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IDT[intnum].zero = 0;
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IDT[intnum].type_attr = 0b10001110; // Active, privilege level 00, storage segment = 0; 32 bit interrupt gate
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IDT[intnum].offset_2 = (uint16_t) ((handler_address & 0xffff0000) >> 16);
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}
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void kb_init() {
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uint8_t mask = inb(0x21);
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mask = mask & ~(1 << 1);
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outb(0x21 , mask);
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}
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__attribute__((interrupt)) void keyboard_handler(struct interrupt_frame* frame) {
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outb(0x20, 0x20);
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char* result = "XXXXXX";
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itoa(frame->eip, result, 16);
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terminal_writestring(result);
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}
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void interrupt_init() {
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/* ICW1 - begin initialization */
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outb(0x20, 0x11);
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outb(0xA0, 0x11);
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/* ICW2 - remap offset address of IDT */
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outb(0x21, 0x20);
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outb(0xA1, 0x82);
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/* ICW3 - setup cascading */
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outb(0x21, 0x00);
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outb(0xA1, 0x00);
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/* ICW4 - environment info */
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outb(0x21, 0x01);
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outb(0xA1, 0x01);
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/* mask interrupts */
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outb(0x21 , 0xff);
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outb(0xA1 , 0xff);
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interrupt_new_handler(0x21, keyboard_handler);
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uint16_t size = (sizeof(idt_entry) * 256);
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terminal_writestring("Size = 0x");
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char* result = "XXXXX";
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itoa(size, result, 16);
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terminal_writestring(result);
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lidt(IDT, size);
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kb_init();
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uint8_t mask = inb(0x21);
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terminal_writestring(" mask = 0b");
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result = "XXXXXXXX";
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itoa(mask, result, 2);
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terminal_writestring(result);
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}
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#endif //INTERRUPTS_C
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