Add: IDT implementation without ISRs

idt.c

@@ -0,0 +1,42 @@
+#include "idt.h"
+#include "system.h"
+
+struct idt_entry
+{
+	unsigned short base_lo;
+	unsigned short sel;
+	unsigned char always0;
+	unsigned char flags;
+	unsigned short base_hi;
+} __attribute__((packed));
+
+struct idt_ptr
+{
+	unsigned short limit;
+	unsigned int base;
+} __attribute__((packed));
+
+struct idt_entry idt[256];
+struct idt_ptr idtp;
+
+extern void idt_load();
+
+void idt_set_gate(unsigned char num, unsigned long base, unsigned short sel, unsigned char flags)
+{
+	idt[num].base_lo = (base & 0xFFFF);
+	idt[num].base_hi = (base >> 16) & 0xFFFF;
+
+	idt[num].sel = sel;
+	idt[num].always0 = 0;
+	idt[num].flags = flags;
+}
+
+void idt_install()
+{
+	idtp.limit = (sizeof (struct idt_entry)*256) - 1;
+	idtp.base = (unsigned int)&idt;
+
+	memset(&idt, 0, sizeof(struct idt_entry)*256);
+
+	idt_load();
+}

idt.h

@@ -0,0 +1,8 @@
+#ifndef IDT_H
+#define IDT_H
+
+void idt_set_gate(unsigned char num, unsigned long base, unsigned short sel, unsigned char flags);
+
+void idt_install();
+
+#endif

kmain.c

@@ -1,11 +1,13 @@
 #include "stdio.h"
 #include "serial.h"
 #include "gdt.h"
+#include "idt.h"
 
 int kmain(int retvalue)
 {
   
   gdt_install();
+  idt_install();
 
   // serial testing
 

loader.s

@@ -38,6 +38,13 @@ gdt_flush:
 flush2:
 	ret
 
+global idt_load
+extern idtp
+
+idt_load:
+	lidt [idtp]
+	ret
+
 section .bss
 align 4 
 kernel_stack:

makefile

@@ -1,4 +1,4 @@
-OBJECTS = loader.o kmain.o stdio.o io.o string.o serial.o gdt.o 
+OBJECTS = loader.o kmain.o stdio.o io.o string.o serial.o gdt.o idt.o system.o 
 CC = gcc
 CFLAGS = -m32 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -Wall -Wextra -c
 LDFLAGS = -T link.ld -melf_i386

system.c

@@ -0,0 +1,8 @@
+#include "system.h"
+
+void *memset(void *dest, char val, size_t count)
+{
+	char *temp = (char *)dest;
+	for(; count != 0; count--) *temp++ = val;
+	return dest;
+}

system.h

@@ -0,0 +1,8 @@
+#ifndef SYSTEM_H
+#define SYSTEM_H
+
+typedef int size_t;
+
+void *memset(void *dest, char val, size_t count);
+
+#endif