From e18ec6d167f95247210095613c5b2178b2bccf8e Mon Sep 17 00:00:00 2001
From: Darkress <30271678+DarkressX@users.noreply.github.com>
Date: Wed, 31 May 2023 20:22:38 +0200
Subject: [PATCH] Started implementation of decfsz Instruction

---
 de/darkress/pic16f84sim/commands/Decfsz.java | 27 ++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 de/darkress/pic16f84sim/commands/Decfsz.java

diff --git a/de/darkress/pic16f84sim/commands/Decfsz.java b/de/darkress/pic16f84sim/commands/Decfsz.java
new file mode 100644
index 0000000..8f5c1b1
--- /dev/null
+++ b/de/darkress/pic16f84sim/commands/Decfsz.java
@@ -0,0 +1,27 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Memory;
+import de.darkress.pic16f84sim.microcontroller.ProgramCounter;
+
+public class Decfsz extends FileRegisterCommandUtils implements Command
+{
+    private final int address;
+    private final boolean destinationBit;
+
+    public Decfsz(int input)
+    {
+        address = input & 0x007F;
+        destinationBit = checkDestinationBit(input);
+    }
+
+    @Override
+    public void execute()
+    {
+        int result = Memory.getRegister(address) + 255; // Allow underflow
+
+        checkZeroBit(result);
+
+        writeToDestination(destinationBit, address, result % 256); // Catch underflow
+        ProgramCounter.incPC();
+    }
+}