We can now receive interrupts

Makefile

@@ -1,8 +1,8 @@
-CFLAGS = -m32 -nostdlib -fno-builtin -fno-exceptions -fno-leading-underscore -fno-pie -fno-stack-protector
+CFLAGS = -m32 -mgeneral-regs-only -nostdlib -fno-builtin -fno-exceptions -fno-leading-underscore -fno-pie -fno-stack-protector -Wno-pointer-to-int-cast
 LDFLAGS = 
 
 DISK_IMG_FILES = kernel.bin hello.bin print.bin boot32.bin kernel32.bin
-KERNEL32_OBJS = screenstuff.o io.o kernel32_strap.o kernel32.o
+KERNEL32_OBJS = screenstuff.o io.o idt.o kernel32_strap.o kernel32.o
 
 run: disk.img
 	qemu-system-x86_64 disk.img
@@ -28,7 +28,7 @@ boot.sector: boot.asm
 kernel32.bin: kernel32.ld $(KERNEL32_OBJS)
 	ld $(LDFLAGS) -T $< $(KERNEL32_OBJS)
 
-kernel32_strap.o: kernel32_strap.asm
+%.o: %.asm
 	nasm -felf32 $< -o $@
 
 %.o: %.c

idt.c

@@ -0,0 +1,30 @@
+#include "idt.h"
+
+GateEntry idt[256];
+
+void set_entry(uint8_t interrupt_number, uint16_t code_segment, void* handler, uint8_t type) {
+  uint32_t handler_addr = (uint16_t)handler;
+  uint16_t* handler_halves = (uint16_t*)&handler_addr;
+  idt[interrupt_number] = (GateEntry){
+    .offset_low = handler_halves[0],
+    .selector = code_segment,
+    .zero = 0,
+    .type = type,
+    .offset_high = handler_halves[1]
+  };
+}
+
+__attribute__((interrupt)) void ignore_interrupt(struct interrupt_frame* frame) {
+  // Do nothing
+}
+
+void init_idt() {
+  idt_desc desc = {.size = 256 * sizeof(GateEntry) - 1, .offset = (uint32_t)idt};
+  asm volatile("lidt %0" : : "m" (desc));
+  for (int i=0; i<256; i++)
+    set_entry(i, 0x08, &ignore_interrupt, 0x8E);
+}
+
+void enable_idt() {
+  asm ("sti");
+}

idt.h

@@ -0,0 +1,32 @@
+#ifndef IDT_H
+#define IDT_H
+
+#include "types.h"
+#include "screenstuff.h"
+
+struct interrupt_frame{
+    uint16_t ip;
+    uint16_t cs;
+    uint16_t flags;
+    uint16_t sp;
+    uint16_t ss;
+};
+extern void load_idt();
+void set_entry(uint8_t interrupt_number, uint16_t code_segment, void* handler, uint8_t type);
+void init_idt();
+void enable_idt();
+
+typedef struct {
+  uint16_t offset_low;
+  uint16_t selector;
+  uint8_t zero;
+  uint8_t type;
+  uint16_t offset_high;
+}__attribute__((packed)) GateEntry;
+
+typedef struct {
+  uint16_t size;
+  uint32_t offset;
+}__attribute__((packed)) idt_desc;
+
+#endif

kernel32.c

@@ -1,13 +1,34 @@
 #include "types.h"
 #include "screenstuff.h"
 #include "io.h"
+#include "idt.h"
+
+__attribute__((interrupt)) void interrupt_21(struct interrupt_frame* frame) {
+  printf("Interrupt 20 received!!\n");
+  outb(0x20, 0x20);
+}
 
 int main() {
+  init_idt();
+  set_entry(0x20, 0x08, &interrupt_21, 0x8E);
   init_term();
 
   printf("KERNEL32 OK!\n");
 
   printf("Hello, World!\n\nWe are running XnoeOS Code in C now, Protected Mode has been achieved and everything is working super nicely!\n\nHow wonderful!\n\nNow I just need to hope my print function works properly too~~\n");
 
+  outb(0x20, 0x11);
+  outb(0xA0, 0x11);
+  outb(0x21, 0x20);
+  outb(0xA1, 0x28);
+  outb(0x21, 0x04);
+  outb(0xA1, 0x02);
+  outb(0x21, 0x01);
+  outb(0xA1, 0x01);
+  outb(0x21, 0x00);
+  outb(0xA1, 0x00);
+
+  enable_idt();
+
   while (1);
 }

types.h

@@ -5,7 +5,7 @@ typedef char int8_t;
 typedef unsigned char uint8_t;
 typedef short int16_t;
 typedef unsigned short uint16_t;
-typedef long long int int32_t;
-typedef unsigned long long int uint32_t;
+typedef long int int32_t;
+typedef unsigned long int uint32_t;
 
 #endif