From 8cb13eb9df20d93987a2a0f991e29f89ba1b0308 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Quei=C3=9Fner?= <git@mq32.de>
Date: Fri, 6 May 2016 09:28:30 +0200
Subject: [PATCH] Adds interrupt handlers.

---
 prototypes/base/Makefile        |  2 +-
 prototypes/base/include/idt.hpp | 57 +++++++++++++++++----------
 prototypes/base/init.cpp        |  7 ++++
 prototypes/base/src/idt.cpp     | 69 +++++++++++++++++++++++++++++++--
 4 files changed, 111 insertions(+), 24 deletions(-)

diff --git a/prototypes/base/Makefile b/prototypes/base/Makefile
index 904d1c7..8aaff01 100644
--- a/prototypes/base/Makefile
+++ b/prototypes/base/Makefile
@@ -47,7 +47,7 @@ kernel-base.ker: $(OBJS)
 
 
 run:
-	qemu-system-i386 -kernel kernel-base.ker -m 64 -d int
+	qemu-system-i386 -kernel kernel-base.ker -m 64
 
 bnr: kernel-base.ker run
 
diff --git a/prototypes/base/include/idt.hpp b/prototypes/base/include/idt.hpp
index 0ac2f4f..965b38d 100644
--- a/prototypes/base/include/idt.hpp
+++ b/prototypes/base/include/idt.hpp
@@ -28,38 +28,44 @@ struct InterruptDescriptor
 	InterruptFlags flags;
 	uint16_t offset1;
 	
-	InterruptDescriptor() : 
-		offset0(0), selector(0), zero(0), flags(InterruptFlags::None), offset1(0)
-	{
+	InterruptDescriptor();
 	
-	}
+	InterruptDescriptor(uint32_t offset, uint32_t selector, InterruptFlags flags);
 	
-	InterruptDescriptor(uint32_t offset, uint32_t selector, InterruptFlags flags) : 
-		offset0(0), selector(selector), zero(0), flags(flags), offset1(0)
-	{
-		this->setOffset(offset);
-	}
-	
-	uint32_t offset() const
-	{
-		return this->offset0 | (this->offset1 << 16);
-	}
-	
-	void setOffset(uint32_t offset)
-	{
-		this->offset0 = (offset & 0x0000FFFF) >> 0;
-		this->offset1 = (offset & 0xFFFF0000) >> 16;
-	}
+	uint32_t offset() const;
 	
+	void setOffset(uint32_t offset);
 } __attribute__((packed));
 
 static_assert(sizeof(InterruptDescriptor) == 8, "InterruptDescriptor must be 8 byte large.");
 
+/**
+ * An interrupt that specifies
+ * a handler and if the interrupt is
+ * enabled. Any non-enabled interrupt
+ * causes a BSOD.
+ */
+class Interrupt
+{
+	friend class IDT;
+	using Handler = void (*)(CpuState *cpu);
+private:
+	bool isEnabled;
+	Handler handler;
+	
+public:
+	Interrupt();
+	explicit Interrupt(Handler handler);
+};
+
 
 class IDT
 {
 public:
 	static const uint32_t length = 256;
+	
+	static Interrupt interrupts[length];
+	
 private:
 	static InterruptDescriptor descriptors[length];
 	IDT() = delete;
@@ -68,8 +74,19 @@ private:
 	static void setupPIC();
 public:
 
+	/**
+	 * Accessor to an interrupt handler.
+	 */
+	static Interrupt & interrupt(uint32_t index);
+
+	/** 
+	 * Gets an interrupt descriptor
+	 */
 	static InterruptDescriptor & descriptor(uint32_t idx);
 
+	/**
+	 * Initializes the interrupt table and sets up the PIC.
+	 */
 	static void initialize();
 	
 };
\ No newline at end of file
diff --git a/prototypes/base/init.cpp b/prototypes/base/init.cpp
index 1d6c694..bfbd422 100644
--- a/prototypes/base/init.cpp
+++ b/prototypes/base/init.cpp
@@ -19,6 +19,11 @@ struct dummy;
 extern dummy kernelStartMarker;
 extern dummy kernelEndMarker;
 
+void timer(CpuState *cpu)
+{
+	Console::main << "tick! ";
+}
+
 extern "C" void init(Structure const & data)
 {
 	Console::main
@@ -83,6 +88,8 @@ extern "C" void init(Structure const & data)
     << (freeMemory >> 12) << "Pages\n";
 
 	IDT::initialize();
+	
+	IDT::interrupt(0x20) = Interrupt(timer);
 
 	Console::main << "Interrupts set up.\n";
 	
diff --git a/prototypes/base/src/idt.cpp b/prototypes/base/src/idt.cpp
index 01bb9cf..8503f31 100644
--- a/prototypes/base/src/idt.cpp
+++ b/prototypes/base/src/idt.cpp
@@ -9,17 +9,28 @@
 #undef ISR
 #undef ISR_ERR
 
-static InterruptDescriptor invalid;
+static InterruptDescriptor invalidDesc;
+static Interrupt invalidIntr;
+
 InterruptDescriptor IDT::descriptors[length];
+Interrupt IDT::interrupts[length];
 
 InterruptDescriptor & IDT::descriptor(uint32_t idx)
 {
 	if(idx >= IDT::length) {
-		return invalid;
+		return invalidDesc;
 	}
 	return IDT::descriptors[idx];
 }
 
+Interrupt & IDT::interrupt(uint32_t index)
+{
+	if(index >= IDT::length) {
+		return invalidIntr;
+	}
+	return IDT::interrupts[index];
+}
+
 void IDT::initialize()
 {
 #define ISR(num) IDT::descriptor(num) = InterruptDescriptor( \
@@ -54,13 +65,22 @@ void IDT::setupPIC()
 
 void IDT::dispatch(CpuState *cpu)
 {
+	Interrupt &intr = IDT::interrupts[cpu->interrupt];
+	if(intr.isEnabled) {
+		(*intr.handler)(cpu);
+	} else {
+		BSOD::die(Error::UnhandledException, "Unhandled Interrupt!", cpu);
+	}
+
 	if(cpu->interrupt <= 0x1F) {
 		// Exception Handling
-		BSOD::die(Error::UnhandledException, "Ermahgerd, Exceptions!", cpu);
+		
 	} else if (cpu->interrupt >= 0x20 && cpu->interrupt <= 0x2F) {
 	
 		// IRQ
 		// Console::main << "[IRQ " << (cpu->interrupt - 0x20) << "]";
+		
+		
 	
 		if(cpu->interrupt >= 0x28) {
 			slavePIC.sendEndOfInterrupt();
@@ -69,4 +89,47 @@ void IDT::dispatch(CpuState *cpu)
 	} else {
 		BSOD::die(Error::UnhandledInterrupt, "Ermahgerd, Interrupts!", cpu);
 	}
+}
+
+
+
+
+Interrupt::Interrupt() :
+	isEnabled(false), 
+	handler(nullptr)
+{
+
+}
+	
+Interrupt::Interrupt(Handler handler) : 
+	isEnabled(true), 
+	handler(handler)
+{
+	
+}
+
+
+
+
+InterruptDescriptor::InterruptDescriptor() : 
+	offset0(0), selector(0), zero(0), flags(InterruptFlags::None), offset1(0)
+{
+
+}
+	
+InterruptDescriptor::InterruptDescriptor(uint32_t offset, uint32_t selector, InterruptFlags flags) : 
+	offset0(0), selector(selector), zero(0), flags(flags), offset1(0)
+{
+	this->setOffset(offset);
+}
+	
+uint32_t InterruptDescriptor::offset() const
+{
+	return this->offset0 | (this->offset1 << 16);
+}
+
+void InterruptDescriptor::setOffset(uint32_t offset)
+{
+	this->offset0 = (offset & 0x0000FFFF) >> 0;
+	this->offset1 = (offset & 0xFFFF0000) >> 16;
 }
\ No newline at end of file