From 41a2a86fd07134668263cf901706d6c0380173a1 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sun, 15 Sep 2019 01:13:31 +0200
Subject: Added interrupt descriptor table and memory setter

---
 src/idt/idt.c | 36 ++++++++++++++++++++++++++++++++++++
 src/idt/idt.h |  6 ++++++
 2 files changed, 42 insertions(+)
 create mode 100644 src/idt/idt.c
 create mode 100644 src/idt/idt.h

(limited to 'src/idt')

diff --git a/src/idt/idt.c b/src/idt/idt.c
new file mode 100644
index 0000000..3c0c246
--- /dev/null
+++ b/src/idt/idt.c
@@ -0,0 +1,36 @@
+#include "../memory/memory.h"
+
+/* Defines an IDT entry */
+struct idt_entry {
+    unsigned short base_lo;
+    unsigned short sel; // Kernel segment
+    unsigned char always0; // Always 0
+    unsigned char flags;
+    unsigned short base_hi;
+} __attribute__((packed));
+
+struct idt_ptr {
+    unsigned short limit;
+    unsigned int base;
+} __attribute__((packed));
+
+// Initialize IDT with 256 entries
+struct idt_entry idt[256];
+struct idt_ptr idtp;
+
+// Defined in boot.asm
+extern void idt_load();
+
+// Install IDT
+void idt_install() {
+    // Set IDT pointer and limit
+    idtp.limit = (sizeof(struct idt_entry) * 256) - 1;
+    idtp.base = &idt;
+
+    // Clear IDT by setting memory cells to 0
+    memory_set(&idt, 0, sizeof(struct idt_entry) * 256);
+
+    // TODO: Add method to add ISRs to IDT
+
+    idt_load();
+}
diff --git a/src/idt/idt.h b/src/idt/idt.h
new file mode 100644
index 0000000..6a68e86
--- /dev/null
+++ b/src/idt/idt.h
@@ -0,0 +1,6 @@
+#ifndef MELVIX_IDT_H
+#define MELVIX_IDT_H
+
+void idt_install();
+
+#endif
-- 
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