From 60b288a76297d7df051f99719a7e979ee27a2862 Mon Sep 17 00:00:00 2001
From: Darkress <30271678+DarkressX@users.noreply.github.com>
Date: Sun, 18 Jun 2023 19:13:37 +0200
Subject: [PATCH] Somewhat working Timer0Interrupt

---
 de/darkress/pic16f84sim/Main.java              |  2 +-
 de/darkress/pic16f84sim/commands/Retfie.java   | 18 ++++++++++++++++++
 .../pic16f84sim/decoder/CommandDecoder.java    |  2 +-
 .../pic16f84sim/microcontroller/Interrupt.java | 14 ++++++++++++++
 .../microcontroller/ProgramCounter.java        |  9 ++++++---
 .../pic16f84sim/microcontroller/Timer.java     |  8 +++++++-
 .../pic16f84sim/microcontroller/Watchdog.java  |  2 +-
 7 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 de/darkress/pic16f84sim/commands/Retfie.java
 create mode 100644 de/darkress/pic16f84sim/microcontroller/Interrupt.java

diff --git a/de/darkress/pic16f84sim/Main.java b/de/darkress/pic16f84sim/Main.java
index aa6dc7c..d083c25 100644
--- a/de/darkress/pic16f84sim/Main.java
+++ b/de/darkress/pic16f84sim/Main.java
@@ -11,7 +11,7 @@ class Main
 {
     public static void main(String[] args) {
 
-        Command[] program = Parser.parser("de/darkress/pic16f84sim/TestPrograms/TPicSim11.LST");
+        Command[] program = Parser.parser("de/darkress/pic16f84sim/TestPrograms/TPicSim8.LST");
 
         Memory.initMemory();
 
diff --git a/de/darkress/pic16f84sim/commands/Retfie.java b/de/darkress/pic16f84sim/commands/Retfie.java
new file mode 100644
index 0000000..f41a868
--- /dev/null
+++ b/de/darkress/pic16f84sim/commands/Retfie.java
@@ -0,0 +1,18 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Cycles;
+import de.darkress.pic16f84sim.microcontroller.Memory;
+import de.darkress.pic16f84sim.microcontroller.ProgramCounter;
+import de.darkress.pic16f84sim.microcontroller.Stack;
+
+public class Retfie extends LiteralCommandUtils implements Command
+{
+    @Override
+    public void execute()
+    {
+        Cycles.incCycles();
+        Memory.setRegister(0x0B, Memory.getRegister(0x0B) | 0x80); //Set GIE
+        ProgramCounter.setPcFromStack(Stack.pop() + 1);
+        Cycles.incCycles(); // Simulate 2-Cycle Instruction
+    }
+}
diff --git a/de/darkress/pic16f84sim/decoder/CommandDecoder.java b/de/darkress/pic16f84sim/decoder/CommandDecoder.java
index 0d480d0..8e7615d 100644
--- a/de/darkress/pic16f84sim/decoder/CommandDecoder.java
+++ b/de/darkress/pic16f84sim/decoder/CommandDecoder.java
@@ -102,7 +102,7 @@ public class CommandDecoder
 
         if (input == 0x0009)
         {
-            //retfie();
+            return new Retfie();
         }
 
         if (input == 0x0008)
diff --git a/de/darkress/pic16f84sim/microcontroller/Interrupt.java b/de/darkress/pic16f84sim/microcontroller/Interrupt.java
new file mode 100644
index 0000000..e2c2ebd
--- /dev/null
+++ b/de/darkress/pic16f84sim/microcontroller/Interrupt.java
@@ -0,0 +1,14 @@
+package de.darkress.pic16f84sim.microcontroller;
+
+public class Interrupt
+{
+    private static boolean globalInterruptEnabled() {
+        return (Memory.getRegister(0x0B) & 0x80) == 0x80;
+
+    }
+    public static boolean checkTimerInterruptConditions() {
+        boolean timerInterruptEnabled = (Memory.getRegister(0x0B) & 0x20) == 0x20;
+        //boolean timerOverflowInterruptFlag = (Memory.getRegister(0x0B) & 0x04) == 0x04;
+        return globalInterruptEnabled() && timerInterruptEnabled;
+    }
+}
diff --git a/de/darkress/pic16f84sim/microcontroller/ProgramCounter.java b/de/darkress/pic16f84sim/microcontroller/ProgramCounter.java
index 9a4e84d..9d584af 100644
--- a/de/darkress/pic16f84sim/microcontroller/ProgramCounter.java
+++ b/de/darkress/pic16f84sim/microcontroller/ProgramCounter.java
@@ -37,8 +37,11 @@ public class ProgramCounter
         Memory.setPCL(pc & 0x00FF);
     }
 
-    public static void resetProgramCounter() {
-        pc = 0;
-        Memory.setPCL(0x0);
+    public static void setProgramCounter(int value) {
+        if(value <= 0xFF && value >= 0)
+        {
+            pc = value;
+            Memory.setPCL(pc);
+        }
     }
 }
diff --git a/de/darkress/pic16f84sim/microcontroller/Timer.java b/de/darkress/pic16f84sim/microcontroller/Timer.java
index cb7d407..99f881c 100644
--- a/de/darkress/pic16f84sim/microcontroller/Timer.java
+++ b/de/darkress/pic16f84sim/microcontroller/Timer.java
@@ -43,9 +43,15 @@ public class Timer
     {
         int timerRegister = Memory.getRegister(0x01);
         timerRegister = (timerRegister + 1) % 256;
-        if(timerRegister == 0) //check for timer Overflow  --> interrupt
+        if(timerRegister == 0 && !((Memory.getRegister(0x0B) & 0x04) == 0x04)) //check for timer Overflow  --> interrupt
         {
             System.out.println("Timer Overflow");
+            Memory.setRegister(0x0B, Memory.getRegister(0x0B) | 0x04); //set T0IF
+            if(Interrupt.checkTimerInterruptConditions())
+            {
+                Stack.push(ProgramCounter.getPc());
+                ProgramCounter.setProgramCounter(0x04); // Interrupt Vector
+            }
         }
         Memory.setTimer(timerRegister);
     }
diff --git a/de/darkress/pic16f84sim/microcontroller/Watchdog.java b/de/darkress/pic16f84sim/microcontroller/Watchdog.java
index 60c5897..456feaa 100644
--- a/de/darkress/pic16f84sim/microcontroller/Watchdog.java
+++ b/de/darkress/pic16f84sim/microcontroller/Watchdog.java
@@ -30,7 +30,7 @@ public class Watchdog
     public static void resetProgram()
     {
         Memory.setRegister(0x03, Memory.getRegister(0x03) | 0x10); //Set !T0 in StatusReg
-        ProgramCounter.resetProgramCounter();
+        ProgramCounter.setProgramCounter(0);
         watchdogTimer = 18000;
     }