Implemented IDT, modified Makefile and boot.S

kernel/Makefile

@@ -25,7 +25,7 @@ CFLAGS:=$(CFLAGS) -ffreestanding -D__is_kernel -Iinclude -Wall -Wextra -Werror
 CPPFLAGS:=$(CPPFLAGS) 
 LDFLAGS:=$(LDFLAGS)
 LIB_INCLUDE_FLAGS=-L./lib/so
-LIBS:=$(LIBS) -nostdlib -lgcc -lklib #-lk -lgcc
+LIBS:=$(LIBS) -nostdlib -lgcc -lklib -lk
 
 # Current architecture directory
 
@@ -37,6 +37,7 @@ include $(ARCHDIR)/make.config
 
 # Updated compiler flags with architecture settings added
 
+CFLAGS+=-I$(KERNEL_ARCH_INCLUDE)
 CFLAGS:=$(CFLAGS) $(KERNEL_ARCH_CFLAGS)
 CPPFLAGS:=$(CPPFLAGS) $(KERNEL_ARCH_CPPFLAGS)
 LDFLAGS:=$(LDFLAGS) $(KERNEL_ARCH_LDFLAGS)

kernel/arch/i386/boot.S

@@ -1,5 +1,5 @@
-#include "gdt.h"
-#include "a20.h"
+#include "tables/gdt.h"
+#include "tables/a20.h"
 
 .global _start
 

kernel/arch/i386/make.config

@@ -5,3 +5,10 @@ KERNEL_ARCH_LIBS=
 
 KERNEL_ARCH_OBJS=\
 $(ARCHDIR)/boot.o \
+$(ARCHDIR)/tables/idt.o \
+$(ARCHDIR)/tables/idt_flush.o \
+$(ARCHDIR)/tables/isr.o \
+$(ARCHDIR)/tables/isr_gate.o \
+
+KERNEL_ARCH_INCLUDE=\
+$(ARCHDIR)/ \

kernel/arch/i386/tables/gdt.h

@@ -69,7 +69,6 @@
  *
  */
 
-
 #define GDT_ENTRY(base, limit, options) \
     (limit & 0x0000FFFF)          | (base << 16)                  | \
     ((((base >> 16) & 0x000000FF) | ((options << 8) & 0x00F0FF00) | \

kernel/arch/i386/tables/idt.c

@@ -0,0 +1,34 @@
+#include "idt.h"
+
+#include "types/idt_types.h"
+
+/* Data structures used to fill the IDT. */
+
+idt_entry_t idt_entries[256];
+idt_ptr_t idt_ptr;
+
+/* Routine that installs the IDT. */
+
+extern void idt_flush(uint32_t idt_ptr);
+
+/*
+ * idt_init:
+ * ---------
+ *
+ *  After the table and the table pointer are filled, flush the table pointer
+ *  using gdt_flush.
+ *
+ */
+
+void idt_init(void) {
+
+    idt_ptr.limit = sizeof(idt_entry_t) * 256 - 1;
+    idt_ptr.base = (uint32_t) &idt_entries;
+
+    for (int i = 0; i < 256; i++)
+        idt_entries[i] = (idt_entry_t) {};
+
+    idt_flush((uint32_t) &idt_ptr);
+
+}
+

kernel/arch/i386/tables/idt.h

@@ -0,0 +1,13 @@
+#ifndef INTRPT_H_
+#define INTRPT_H_
+
+/*
+ * idt_init:
+ *  Creates an array of 256 empty entries that will be loaded in the CPU as
+ *  an IDT.
+ *
+ */
+
+void idt_init(void);
+
+#endif

kernel/arch/i386/tables/idt_flush.S

@@ -0,0 +1,15 @@
+.global idt_flush
+
+/*
+ * idt_flush - load the 48bit memory that contains the information about
+ * the IDT in its corresponding register using the LIDT instruction.
+ *
+ * @param [esp + 4] - pointer to a 48bit memory location
+ *
+ */
+
+idt_flush:
+
+    mov 0x04(%esp), %eax
+    lidt (%eax)
+    ret

kernel/arch/i386/tables/types/idt_types.h

@@ -0,0 +1,49 @@
+#ifndef INTRPT_IDT_H_
+#define INTRPT_IDT_H_
+
+#include "stdint.h"
+
+/*
+ * idt_entry_t  - entry in Interrupt Descriptor Table
+ * idt_set_gate - creates an IDT entry
+ *
+ */
+
+struct idt_entry_struct {
+
+    uint16_t base_low;
+    uint16_t selector;
+    uint8_t  zero;
+    uint8_t  flags;
+    uint16_t base_high;
+
+} __attribute__((packed));
+
+typedef struct idt_entry_struct idt_entry_t;
+
+
+static inline idt_entry_t idt_set_gate(uint32_t base, uint16_t sel, uint8_t flags) {
+
+    idt_entry_t entry;
+
+    entry.base_low = base & 0xFFFF;
+    entry.selector = sel;
+    entry.zero = 0x00;
+    entry.flags = flags;
+    entry.base_high = (base >> 16) & 0xFFFF;
+
+    return entry;
+}
+
+/* idt_ptr_t - IDT pointer that will be loaded in CPU */
+
+struct idt_ptr_struct {
+
+    uint16_t limit;
+    uint32_t base;
+
+} __attribute__((packed));
+
+typedef struct idt_ptr_struct idt_ptr_t;
+
+#endif