interrupt descriptor table setup, but has no handlers yet

interrupts.c

@@ -1,10 +1,34 @@
 #include "interrupts.h"
+#include "mem.h"
 #include "types.h"
 
+void setup_idt_entry(u32 t_idx, u32 base, u16 sel, u8 type_attrs) {
+	// Configuring a single given entry in the IDT table
+	IDT[t_idx].offset_low = (base & 0xffff);
+	IDT[t_idx].offset_high = ((base >> 16) & 0xffff);
+
+	IDT[t_idx].type_attrs = type_attrs;
+	IDT[t_idx].selector = sel;
+}
+
 void load_idt() {
 	asm("lidt [idt_ptr]");
 	return;
 }
 
+// Generic interrupt handler to be used later on
 //void interrupt_handler(struct cpu_reg_state cpu, struct stack_state stack, u32 interrupt_code) {
 //}
+
+void init_idt() {
+	// setup special idt pointer
+	idt_ptr.address = (u32)(&IDT);
+	idt_ptr.limit = sizeof(struct IDT_Entry) * IDT_SIZE;
+	// clear table
+	memset((u8*)IDT, 0x00, (sizeof(struct IDT_Entry) * IDT_SIZE) - 1);
+	// add interrupt service routines here
+	// TODO
+
+	// Load IDT with all the new information in place, ready to use
+	load_idt();
+}

interrupts.h

@@ -1,5 +1,6 @@
 #include "types.h"
 
+
 struct cpu_reg_state {
 	u32 eax;
 	u32 ebx;
@@ -30,6 +31,8 @@ struct stack_state {
 	u32 eflags;
 };
 
+#define IDT_SIZE 256
+
 struct IDT_Entry {
 	u16 offset_low; // offset bits 0..15
 	u16 selector; 	// code segment in either gdt or ldt
@@ -48,8 +51,10 @@ struct IDT_PTR {
 	u32 address;
 }__attribute__((packed));
 
-struct IDT_Entry IDT[255];
+struct IDT_Entry IDT[IDT_SIZE];
 struct IDT_PTR idt_ptr;
 
-//void interrupt_handler(struct cpu_reg_state, struct stack_state, u32);
 void load_idt();
+void init_idt();
+void setup_idt_entry(u32 t_idx, u32 base, u16 sel, u8 type_attrs);
+//void interrupt_handler(struct cpu_reg_state, struct stack_state, u32);

kernel.c

@@ -1,10 +1,12 @@
+#include "kernel.h"
 #include "types.h"
 #include "tests.h"
+#include "interrupts.h"
 #include "gdt.h"
-#include "kernel.h"
 
 void kinit() {
 	gdt_configure();
+	init_idt();
 	test_dispatcher();
 }
 

makefile

@@ -3,7 +3,8 @@ ASM=nasm
 LINK=ld
 ISO=genisoimage
 
-OBJECTS=kernel.o gdt_seg.o gdt.o interrupts.o loader.o serial.o framebuffer.o ports.o stlio.o tests.o
+OBJECTS=mem.o kernel.o gdt_seg.o gdt.o interrupts.o loader.o serial.o \
+		framebuffer.o ports.o stlio.o tests.o
 AFLAGS=-f elf32
 CFLAGS=-masm=intel -O2 -m32 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles \
 		-nodefaultlibs -Wall -Wextra -Werror -c