From c5b4666b50785c5be83e94b602cac70d81489440 Mon Sep 17 00:00:00 2001
From: Alex <enderice2@users.noreply.github.com>
Date: Mon, 17 Oct 2022 01:43:00 +0300
Subject: [PATCH] Implemented PIC (untested code)

---
 Core/Interrupts/8259PIC.cpp | 123 ++++++++++++++++++++++++++++++++++++
 Core/Interrupts/pic.hpp     |  42 ++++++++++++
 2 files changed, 165 insertions(+)
 create mode 100644 Core/Interrupts/8259PIC.cpp
 create mode 100644 Core/Interrupts/pic.hpp

diff --git a/Core/Interrupts/8259PIC.cpp b/Core/Interrupts/8259PIC.cpp
new file mode 100644
index 0000000..b04aeec
--- /dev/null
+++ b/Core/Interrupts/8259PIC.cpp
@@ -0,0 +1,123 @@
+#include "pic.hpp"
+
+#include <io.h>
+
+namespace PIC
+{
+    PIC::PIC(uint8_t MasterCommandPort, uint8_t MasterDataPort, uint8_t SlaveCommandPort, uint8_t SlaveDataPort, uint8_t MasterOffset, uint8_t SlaveOffset)
+    {
+        this->MasterCommandPort = MasterCommandPort;
+        this->MasterDataPort = MasterDataPort;
+        this->SlaveCommandPort = SlaveCommandPort;
+        this->SlaveDataPort = SlaveDataPort;
+        this->MasterOffset = MasterOffset;
+        this->SlaveOffset = SlaveOffset;
+
+        MasterMask = 0xFF;
+        SlaveMask = 0xFF;
+
+        // ICW1
+        outb(MasterCommandPort, 0x11);
+        outb(SlaveCommandPort, 0x11);
+
+        // ICW2
+        outb(MasterDataPort, MasterOffset);
+        outb(SlaveDataPort, SlaveOffset);
+
+        // ICW3
+        outb(MasterDataPort, 0x04);
+        outb(SlaveDataPort, 0x02);
+
+        // ICW4
+        outb(MasterDataPort, 0x01);
+        outb(SlaveDataPort, 0x01);
+
+        // OCW1
+        outb(MasterDataPort, MasterMask);
+        outb(SlaveDataPort, SlaveMask);
+    }
+
+    PIC::~PIC()
+    {
+        outb(MasterDataPort, 0xFF);
+        outb(SlaveDataPort, 0xFF);
+    }
+
+    void PIC::Mask(uint8_t IRQ)
+    {
+        uint16_t Port;
+        uint8_t Value;
+
+        if (IRQ < 8)
+        {
+            Port = MasterDataPort;
+            Value = MasterMask & ~(1 << IRQ);
+            MasterMask = Value;
+        }
+        else
+        {
+            Port = SlaveDataPort;
+            Value = SlaveMask & ~(1 << (IRQ - 8));
+            SlaveMask = Value;
+        }
+
+        outb(Port, Value);
+    }
+
+    void PIC::Unmask(uint8_t IRQ)
+    {
+        uint16_t Port;
+        uint8_t Value;
+
+        if (IRQ < 8)
+        {
+            Port = MasterDataPort;
+            Value = MasterMask | (1 << IRQ);
+            MasterMask = Value;
+        }
+        else
+        {
+            Port = SlaveDataPort;
+            Value = SlaveMask | (1 << (IRQ - 8));
+            SlaveMask = Value;
+        }
+
+        outb(Port, Value);
+    }
+
+    void PIC::SendEOI(uint8_t IRQ)
+    {
+        if (IRQ >= 8)
+            outb(SlaveCommandPort, 0x20);
+
+        outb(MasterCommandPort, 0x20);
+    }
+
+    PIT::PIT(uint16_t Port, uint16_t Frequency)
+    {
+        this->Port = Port;
+        this->Frequency = Frequency;
+    }
+
+    PIT::~PIT()
+    {
+    }
+
+    void PIT::PrepareSleep(uint32_t Milliseconds)
+    {
+        uint16_t Divisor = 1193182 / Frequency;
+        uint8_t Low = (uint8_t)(Divisor & 0xFF);
+        uint8_t High = (uint8_t)((Divisor >> 8) & 0xFF);
+
+        outb(Port + 3, 0x36);
+        outb(Port + 0, Low);
+        outb(Port + 1, High);
+    }
+
+    void PIT::PerformSleep()
+    {
+        uint8_t Value = inb(Port + 0);
+        while (Value != 0)
+            Value = inb(Port + 0);
+    }
+}
diff --git a/Core/Interrupts/pic.hpp b/Core/Interrupts/pic.hpp
new file mode 100644
index 0000000..893e73b
--- /dev/null
+++ b/Core/Interrupts/pic.hpp
@@ -0,0 +1,42 @@
+#ifndef __FENNIX_KERNEL_8259PIC_H__
+#define __FENNIX_KERNEL_8259PIC_H__
+
+#include <types.h>
+
+namespace PIC
+{
+    class PIC
+    {
+    private:
+        uint8_t MasterCommandPort;
+        uint8_t MasterDataPort;
+        uint8_t SlaveCommandPort;
+        uint8_t SlaveDataPort;
+        uint8_t MasterOffset;
+        uint8_t SlaveOffset;
+        uint8_t MasterMask;
+        uint8_t SlaveMask;
+
+    public:
+        PIC(uint8_t MasterCommandPort, uint8_t MasterDataPort, uint8_t SlaveCommandPort, uint8_t SlaveDataPort, uint8_t MasterOffset, uint8_t SlaveOffset);
+        ~PIC();
+        void Mask(uint8_t IRQ);
+        void Unmask(uint8_t IRQ);
+        void SendEOI(uint8_t IRQ);
+    };
+
+    class PIT
+    {
+    private:
+        uint16_t Port;
+        uint16_t Frequency;
+
+    public:
+        PIT(uint16_t Port, uint16_t Frequency);
+        ~PIT();
+        void PrepareSleep(uint32_t Milliseconds);
+        void PerformSleep();
+    };
+}
+
+#endif // !__FENNIX_KERNEL_8259PIC_H__