From 158cbf443d5e4a65d4a499cfc9cf5ca81c4c9458 Mon Sep 17 00:00:00 2001
From: Anachronaut <75824887+RealBusinessAccount@users.noreply.github.com>
Date: Thu, 17 Oct 2024 18:40:54 -0400
Subject: [PATCH] Bug fixes

Added stack collision detection.
Added SETD instruction.
---
 Source/bootstrap.c |  2 +-
 Source/cpu.c       | 15 ++++++++++++++-
 Source/emulator.c  | 10 ++++++----
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/Source/bootstrap.c b/Source/bootstrap.c
index f7e6c2d..fd88f17 100644
--- a/Source/bootstrap.c
+++ b/Source/bootstrap.c
@@ -25,7 +25,7 @@ uint32_t readLength(FILE *file) {
 }
 
 uint32_t readHeader(FILE *file, const char *expectedHeader) {
-    uint8_t header[HEADER_LENGTH];
+    char header[HEADER_LENGTH];
     for (int i = 0; i < HEADER_LENGTH; i++) {
         int byte = fgetc(file);
         if (byte == EOF) {
diff --git a/Source/cpu.c b/Source/cpu.c
index 265e3be..6148321 100644
--- a/Source/cpu.c
+++ b/Source/cpu.c
@@ -5,7 +5,6 @@
 
 #include "cpu.h"
 #include "io.h"
-#include <stdio.h>
 
 void initializeCPU(CPURegisters *cpu, uint8_t *programMemory, uint8_t *dataMemory) {
     cpu->A = 0;
@@ -247,6 +246,15 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
             // STB - Store B into Data.
             cpu->Data[cpu->DataPointer] = cpu->B;
         break;
+        case 0x47:
+            // SETD - Set the Data Pointer.
+            cpu->ProgramCounter++;
+            uint16_t Address;
+            Address = (uint16_t)cpu->Program[cpu->ProgramCounter] << 8; // Cast the 8 bits to a 16 bit value and shift them to the high byte.
+            cpu->ProgramCounter++;
+            Address |= (uint16_t)cpu->Program[cpu->ProgramCounter];
+            cpu-> DataPointer = Address;
+        break;
         //
         // Dx - Output Operations:
         //
@@ -301,5 +309,10 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
             // Unknown Instruction.
             return 1;
     }
+    if (cpu->DataPointer >= cpu->StackPointer) {
+        // A Stack Collision was detected.
+        cpu->Status |= 0x82; // Set Stack Collision Flag and Halt . (Bits 7 and 1 of the Status Register);
+        return 2;
+    }
     return 0;
 }
diff --git a/Source/emulator.c b/Source/emulator.c
index 5198e3f..11e2a84 100644
--- a/Source/emulator.c
+++ b/Source/emulator.c
@@ -47,15 +47,17 @@ int main (int argc, char *argv[]) {
     }
     CPURegisters cpu;
     initializeCPU(&cpu, Program, Data);
+    if(debugEnable) {
+        printRegisters(&cpu, Program, Data);
+    }
     while (!(cpu.Status & 0x80)) {
+        executeOperation(cpu.Program[cpu.ProgramCounter], &cpu);
+        cpu.ProgramCounter++;
+        cycleCount++;
         if (debugEnable) {
             getchar();
             printRegisters(&cpu, Program, Data);
         }
-
-        executeOperation(cpu.Program[cpu.ProgramCounter], &cpu);
-        cpu.ProgramCounter++;
-        cycleCount++;
     }
     printf("Execution halted after %u cycles.\n", cycleCount);
 }