From 60450253cdfac9c098d76f01efff34d4ee1dfae4 Mon Sep 17 00:00:00 2001
From: Anachronaut <75824887+RealBusinessAccount@users.noreply.github.com>
Date: Fri, 18 Oct 2024 16:23:03 -0400
Subject: [PATCH] Assorted bug fixes. Added INIA and INIB instructions.

---
 Source/cpu.c                   | 16 ++++++++++------
 Source/emulator.c              |  1 +
 SplitBit Programming Manual.md |  4 ++++
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/Source/cpu.c b/Source/cpu.c
index 6148321..29c5c43 100644
--- a/Source/cpu.c
+++ b/Source/cpu.c
@@ -150,12 +150,14 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
             cpu->B = cpu->Data[cpu->DataPointer];
         break;
         case 0x28:
-            // INCD - Add 1 to the Data Pointer.
-            cpu->DataPointer++;
+            // INIA - Initialize A Immediately from Program Memory.
+            cpu->ProgramCounter++;
+            cpu->A = cpu->Data[cpu->ProgramCounter];
         break;
         case 0x29:
-            // DECD - Subtract 1 from the Data Pointer.
-            cpu->DataPointer--;
+            // INIB - Initialize A Immediately from Program Memory.
+            cpu->ProgramCounter++;
+            cpu->B = cpu->Data[cpu->ProgramCounter];
         break;
         //
         // 3x - Stack Operations:
@@ -193,19 +195,21 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
         break;
         case 0x35:
             // POPA - Pop Data to A.
-            cpu->A = cpu->Data[cpu->StackPointer];
             cpu->StackPointer++;
+            cpu->A = cpu->Data[cpu->StackPointer];
+
         break;
         case 0x36:
             // POPB - Pop Data to B.
-            cpu->B = cpu->Data[cpu->StackPointer];
             cpu->StackPointer++;
+            cpu->B = cpu->Data[cpu->StackPointer];
         break;
         case 0x37:
             // POPP - Pop Data to the Program Counter
             cpu->ProgramCounter = (uint16_t)cpu->Data[cpu->StackPointer] << 8;
             cpu->StackPointer++;
             cpu->ProgramCounter = cpu->ProgramCounter | (uint16_t)cpu->Data[cpu->StackPointer];
+            cpu->ProgramCounter += 3; // Because it needs to skip over the subsequent branch instruction on return.
             cpu->StackPointer++;
         break;
         case 0x38:
diff --git a/Source/emulator.c b/Source/emulator.c
index 11e2a84..1216be6 100644
--- a/Source/emulator.c
+++ b/Source/emulator.c
@@ -57,6 +57,7 @@ int main (int argc, char *argv[]) {
         if (debugEnable) {
             getchar();
             printRegisters(&cpu, Program, Data);
+            printf("Cycle: %u\n", cycleCount);
         }
     }
     printf("Execution halted after %u cycles.\n", cycleCount);
diff --git a/SplitBit Programming Manual.md b/SplitBit Programming Manual.md
index bdd6433..5380821 100644
--- a/SplitBit Programming Manual.md	
+++ b/SplitBit Programming Manual.md	
@@ -46,6 +46,10 @@ Hex Code | Mnemonic | Description
 | 23       | INCB     | Adds 1 to B.        |
 | 24       | DECA     | Subtracts 1 from A. |
 | 25       | DECB     | Subtracts 1 from B. |
+| 26       | LDA	  | Loads Data to A via the Data Pointer. |
+| 27	   | LDB      | Loads Data to B via the Data Pointer.
+| 28	   | INIA     | Loads the next byte of Program Memory to A. |
+| 29       | INIB     | Loads the next byte of Program Memory to B. |
 
 ### Stack Operations: 9 Instructions
 Hex Code | Mnemonic | Description