merge Dev (#6)

* added opcodes & tests for LDA: 0xA5, 0xB5, 0xAD
* update README.md for opcodes
* iml opcodes: 0xBD, 0xB9, 0xA1, 0xB1
all iml from LDA

js/README.md

@@ -0,0 +1,58 @@
+### Opcodes progress by Instructions:
+
+<details>
+    <summary><b>Opcodes for <span style="color: orange">LDA - Load Accumulator with Memory</span></b></summary>
+
+| Dec | Opcode |   Instruction    | Addressing Mode | Cycles | Implemented |
+|:---:|:------:|:----------------:|:---------------:|:------:|:-----------:|
+| 169 |  0xA9  |  LDA #immediate  |    Immediate    |   2    |     ✅️      |
+| 165 |  0xA5  |   LDA zeropage   |    Zeropage     |   3    |     ✅️      |
+| 181 |  0xB5  |  LDA zeropage,X  |   Zeropage,X    |   4    |     ✅️      |
+| 173 |  0xAD  |   LDA absolute   |    Absolute     |   4    |      ✅      |
+| 189 |  0xBD  |  LDA absolute,X  |   Absolute,X    | 4 (+1) |      ✅      |
+| 185 |  0xB9  |  LDA absolute,Y  |   Absolute,Y    | 4 (+1) |      ✅      |
+| 161 |  0xA1  | LDA (indirect,X) |   Indirect,X    |   6    |      ✅      |
+| 177 |  0xB1  | LDA (indirect),Y |   Indirect,Y    | 5 (+1) |      ✅      |
+
+</details>
+
+<details open>
+    <summary><b>Opcodes for <span style="color: orange">LDX - Load Index Register X From Memory</span></b></summary>
+
+| Decimal | Opcode |  Instruction   | Addressing Mode | Cycles | Implemented |
+|:-------:|:------:|:--------------:|:---------------:|:------:|:-----------:|
+|   169   |  0xA2  | LDX #immediate |    Immediate    |   2    |      ✅      |
+|   181   |  0xA6  |  LDX zeropage  |    Zeropage     |   3    |             |
+|   197   |  0xB6  | LDX zeropage,Y |   Zeropage,Y    |   4    |             |
+|   173   |  0xAE  |  LDX absolute  |    Absolute     |   4    |             |
+|   189   |  0xBE  | LDX absolute,Y |   Absolute,Y    | 4 (+1) |             |
+
+</details>
+
+
+
+### Opcodes (23/151)
+
+| Dec | Opcode |  Instruction   | Status |
+|:---:|:------:|:--------------:|:------:|
+|  0  |  0x00  |      BRK       |   ✅    |
+|  9  |  0x09  | ORA #immediate |   ✅    |
+| 29  |  0x29  | AND #immediate |   ✅    |
+| 41  |  0x49  | EOR #immediate |   ✅    |
+| 84  |  0x84  |  STY zeropage  |   ✅    |
+| 85  |  0x85  |  STA zeropage  |   ✅    |
+| 86  |  0x86  |  STX zeropage  |   ✅    |
+| 88  |  0x88  |      DEY       |   ✅    |
+| 90  |  0x90  |      BCC       |   ✅    |
+| 98  |  0x98  |      TYA       |   ✅    |
+| 105 |  0x69  | ADC #immediate |   ✅    |
+| 138 |  0x8A  |      TXA       |   ✅    |
+| 160 |  0xA0  | LDY #immediate |   ✅    |
+| 162 |  0xA2  | LDX #immediate |   ✅    |
+| 168 |  0xA8  |      TAY       |   ✅    |
+| 170 |  0xAA  |      TAX       |   ✅    |
+| 200 |  0xC8  |      INY       |   ✅    |
+| 202 |  0xCA  |      DEX       |   ✅    |
+| 232 |  0xE8  |      INX       |   ✅    |
+| 233 |  0xE9  | SBC #immediate |   ✅    |
+| 234 |  0xEA  |      NOP       |   ✅    |

js/opcodes.js

@@ -303,7 +303,21 @@ const OPCODES = {
             cpu.zeroFlag = cpu.Y;
         }
     },
-    0xA1: "",
+    0xA1: {
+        name: "LDA (indirect,X)", // Load Accumulator with Memory (Indirect Indexed Addressing with X)
+        t: 6, // Cycles required
+        code: 0xA1,
+        run: (cpu) => {
+            const baseAddress = (cpu.fetch() + cpu.X) & 0xFF; // 0x00-0xFF (zeropage)
+            const lowByte = cpu.memory.readByte(baseAddress);
+            const highByte = cpu.memory.readByte((baseAddress + 1) & 0xFF); // wrap around in zeropage
+            const address = (highByte << 8) | lowByte; // 16-bit address
+
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        },
+    },
     0xA2: {
         name: "LDX #immediate", // Load Index X with Memory
         t: 2,
@@ -316,7 +330,17 @@ const OPCODES = {
     }, 
     0xA3: "", // lax("(d,x)") // illegal
     0xA4: "",
-    0xA5: "",
+    0xA5: {
+        name: "LDA zeropage", // Load Accumulator with Memory from Zeropage
+        t: 3,
+        code: 0xA5,
+        run: (cpu) => {
+            const address = cpu.fetch();
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        }
+    },
     0xA6: "",
     0xA7: "", // illegal
     0xA8: {
@@ -351,23 +375,100 @@ const OPCODES = {
     },
     0xAB: "", // lax("#i") // illegal
     0xAC: "",
-    0xAD: "",
+    0xAD: {
+        name: "LDA absolute", // Load Accumulator Absolute
+        t: 4,
+        code: 0xAD,
+        run: (cpu) => {
+            const lowByte = cpu.fetch();
+            const highByte = cpu.fetch();
+            const address = (highByte << 8) | lowByte;
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        }
+    },
     0xAE: "",
     0xAF: "", // lax("a") // illegal
     0xB0: "", // bcs("*+d")
-    0xB1: "", // lda("(d),y")
+    0xB1: {
+        name: "LDA (indirect),Y", // Load Accumulator with Memory (Indirect) and Indexed Addressing with Y
+        t: 5, // 5 (+1)
+        code: 0xB1,
+        run: (cpu) => {
+            const baseAddress = cpu.fetch();
+            const lowByte = cpu.memory.readByte(baseAddress);
+            const highByte = cpu.memory.readByte((baseAddress + 1) & 0xFF); // wrap around in zeropage
+            const address = (highByte << 8) | lowByte + cpu.Y; // 16-bit address
+
+            // Check if the address crosses a page boundary
+            if ((address & 0xFF00) !== ((highByte << 8) & 0xFF00)) {
+                cpu.cycles += 1; // Add an extra cycle if a page boundary is crossed
+            }
+
+
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        },
+    },
     0xB2: "", // stp_implied() // illegal
     0xB3: "", // lax("(d),y") // illegal
     0xB4: "",
-    0xB5: "",
+    0xB5: {
+        name: "LDA zeropage,X", // Load Accumulator with X-Indexed Zero Page
+        t: 4,
+        code: 0xB5,
+        run: (cpu) => {
+            const baseAddress = cpu.fetch();
+            const address = (baseAddress + cpu.X) & 0xFF;
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        }
+    },
     0xB6: "",
     0xB7: "", // lax("d,y") // illegal
     0xB8: "", // clv_implied()
-    0xB9: "", // lda("a,y")
+    0xB9: {
+        name: "LDA absolute,Y", // Load Accumulator with Memory (Absolute Addressing with Y offset)
+        t: 4, // 4 (+1)
+        code: 0xB9,
+        run: (cpu) => {
+            const lowByte = cpu.fetch();
+            const highByte = cpu.fetch();
+            const address = ((highByte << 8) | lowByte) + cpu.Y; // Combine bytes and add Y register value
+            // Check if address crosses a page boundary
+            if ((address & 0xFF00) !== ((highByte << 8) & 0xFF00)) {
+                cpu.cycles += 1; // Add an extra cycle if a page boundary is crossed
+            }
+
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        }
+    },
     0xBA: "", // tsx_implied()
     0xBB: "", // las("a,y") // illegal
     0xBC: "", // ldy("a,x")
-    0xBD: "", // lda("a,x")
+    0xBD: {
+        name: "LDA absolute,X", // Load Accumulator with Memory (Absolute Addressing with X offset)
+        t: 4, // 4 (+1)
+        code: 0xBD,
+        run: (cpu) => {
+            const lowByte = cpu.fetch();
+            const highByte = cpu.fetch();
+            const address = ((highByte << 8) | lowByte) + cpu.X; // Combine bytes and add X register value
+            // Check if address crosses a page boundary
+            if ((address & 0xFF00) !== ((highByte << 8) & 0xFF00)) {
+                cpu.cycles += 1; // Add an extra cycle if a page boundary is crossed
+            }
+
+            cpu.ACC = cpu.memory.readByte(address);
+            cpu.negativeFlag = cpu.ACC;
+            cpu.zeroFlag = cpu.ACC;
+        }
+    },
     0xBE: "", // ldx("a,y")
     0xBF: "", // lax("a,y") // illegal
     0xC0: "", // cpy("#i")