From 99019721a9e147c49becc466c5427609b937aca8 Mon Sep 17 00:00:00 2001
From: Loic Guegan <manzerbredes@mailbox.org>
Date: Wed, 21 Apr 2021 18:54:50 +0200
Subject: Enable interrupts

---
 src/core/idt.cc | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 src/core/idt.cc

(limited to 'src/core/idt.cc')

diff --git a/src/core/idt.cc b/src/core/idt.cc
new file mode 100644
index 0000000..b808625
--- /dev/null
+++ b/src/core/idt.cc
@@ -0,0 +1,51 @@
+#include "idt.hpp"
+#include "libs/string.hpp"
+
+IDT_REGISTER IDTR = {
+    IDT_GATE_SIZE*IDT_MAX_ENTRIES,
+    IDT_ADDR
+};
+
+extern u64 INT_DEFAULT,INT_0,INT_14;
+
+void idt_enable_interrupt(void){
+    IDT_DESCRIPTOR d;
+    d.ign=0;
+    d.ist=0;
+    d.selector=0x08;
+    d.options=IDT_OPT_P|IDT_OPT_PRVL_0|IDT_OPT_TYPE_INT;
+
+    // Write idt entries
+    for(u16 i=0;i<IDT_MAX_ENTRIES;i++){
+        if(i==0){ // Zero-division
+            d.offset=(u64)&INT_0;
+            idt_write_descriptor(d, i);
+        }
+        else if(i==14){ // Page fault
+            d.offset=(u64)&INT_14;
+            idt_write_descriptor(d, i);
+        }
+        else {
+            d.offset=(u64)&INT_DEFAULT;
+            idt_write_descriptor(d, i);
+        }
+    }
+
+    // Enable interrupts
+    asm(
+        "lidt (IDTR)   \n\t"
+        "sti           \n\t"
+    );
+}
+
+void idt_write_descriptor(IDT_DESCRIPTOR desc, u16 index){
+    u32 desc0_31=(desc.selector << 16) | desc.offset&0xFFFF;
+    u32 desc32_63=desc.ist | desc.options | (desc.offset&0xFFFF0000);
+    u32 desc64_95=desc.offset>>32;
+    u32 desc96_127=desc.ign;
+    u32* dst=(u32*)(IDTR.base+index*IDT_GATE_SIZE);
+    *dst=desc0_31;
+    *(dst+1)=desc32_63;
+    *(dst+2)=desc64_95;
+    *(dst+3)=desc96_127;
+}
\ No newline at end of file
-- 
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