From b924e632cf80bb23fcaccf36c6371bb997ef1fb2 Mon Sep 17 00:00:00 2001
From: Nathan Giddings <nathang567@gmail.com>
Date: Sun, 2 Aug 2020 15:07:23 -0500
Subject: [PATCH] Fixed x86 lidt function, added addSyscall() method

---
 src/interrupts.hpp     |  8 ++++++++
 src/x86/interrupts.cpp | 13 ++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/interrupts.hpp b/src/interrupts.hpp
index 173a002..d51d864 100644
--- a/src/interrupts.hpp
+++ b/src/interrupts.hpp
@@ -7,12 +7,20 @@ namespace kernel
     {
     public:
 
+        static const unsigned int MAX_SYSCALL_ID = 31;
+
         Interrupts();
 
         void enable();
 
         void disable();
 
+        void addSyscall(unsigned int id, void* function);
+
+    private:
+
+        void* syscalls[MAX_SYSCALL_ID + 1];
+
     };
 }
 
diff --git a/src/x86/interrupts.cpp b/src/x86/interrupts.cpp
index 2b22417..c825113 100644
--- a/src/x86/interrupts.cpp
+++ b/src/x86/interrupts.cpp
@@ -1,6 +1,7 @@
 #include "../interrupts.hpp"
 
 #include <stdint.h>
+#include <stddef.h>
 
 class InterruptDescriptor
 {
@@ -59,7 +60,9 @@ void lidt()
     IDTInfo idtInfo;
     idtInfo.size = sizeof(idt) - 1;
     idtInfo.location = (void*) &idt;
-    asm("lidt idt");
+    asm("lidt (%0)"
+        :
+        : "r" (&idtInfo));
 }
 
 __attribute__ ((interrupt))
@@ -156,6 +159,8 @@ void* InterruptDescriptor::operator=(void* rhs)
 
 kernel::Interrupts::Interrupts()
 {
+    for(unsigned int i = 0; i <= MAX_SYSCALL_ID; i++)
+        syscalls[i] = (void*) NULL;
     idt[0] = InterruptDescriptor((void*) &divisionByZero, InterruptDescriptor::INT32, 0);
     idt[8] = InterruptDescriptor((void*) &doubleFaultHandler, InterruptDescriptor::INT32, 0);
     idt[0x80] = InterruptDescriptor((void*) &syscallHandler, InterruptDescriptor::INT32, 0);
@@ -172,4 +177,10 @@ void kernel::Interrupts::enable()
 void kernel::Interrupts::disable()
 {
     asm("cli");
+}
+
+void kernel::Interrupts::addSyscall(unsigned int id, void* function)
+{
+    if(id <= MAX_SYSCALL_ID)
+        syscalls[id] = function;
 }
\ No newline at end of file