Fixes labels, adds more tests

app/src/main/kotlin/android/emu6502/Assembler.kt

@@ -2,18 +2,28 @@ package android.emu6502
 
 import android.emu6502.instructions.Instruction
 import android.emu6502.instructions.Opcodes
+import android.emu6502.instructions.Symbols
+import java.util.HashMap
 import java.util.regex.Pattern
 import kotlin.text.Regex
 
-class Assembler(private var labels: Labels, private var memory: Memory,
-    private var symbols: Symbols) {
+class Assembler(private var memory: Memory, private val symbols: Symbols) {
 
   var codeLen = 0
   val BOOTSTRAP_ADDRESS = 0x600
   var defaultCodePC = BOOTSTRAP_ADDRESS
+  private var labels = Labels(this, symbols)
 
   fun assembleCode(lines: List<String>) {
-    lines.forEachIndexed { i, line ->
+    val preprocessedLines = preprocess(lines)
+
+    labels.indexLines(preprocessedLines)
+
+    // Reset PC and code length since labels screwed it
+    defaultCodePC = BOOTSTRAP_ADDRESS
+    codeLen = 0
+
+    preprocessedLines.forEachIndexed { i, line ->
       if (!assembleLine(line)) {
         throw RuntimeException("**Syntax error line " + (i + 1) + ": " + line + "**")
       }
@@ -22,7 +32,24 @@ class Assembler(private var labels: Labels, private var memory: Memory,
     memory.set(defaultCodePC, 0x00)
   }
 
-  private fun assembleLine(line: String): Boolean {
+  private fun preprocess(lines: List<String>): List<String> {
+    val pattern = Pattern.compile("^define\\s+(\\w+)\\s+(\\S+)", Pattern.CASE_INSENSITIVE)
+
+    var sanitizedLines = lines.map { sanitize(it) }
+
+    sanitizedLines
+        .map { pattern.matcher(it) }
+        .filter { it.find() }
+        .forEach { symbols.put(it.group(1), sanitize(it.group(2))) }
+
+    return sanitizedLines.filterNot { pattern.matcher(it).find() }
+  }
+
+  private fun sanitize(line: String): String {
+    return line.replace("^(.*?);.*".toRegex(), "$1").trim()
+  }
+
+  fun assembleLine(line: String): Boolean {
     var input = line
     var command: String
     var param: String
@@ -56,7 +83,7 @@ class Assembler(private var labels: Labels, private var memory: Memory,
       } else {
         addr = Integer.parseInt(param, 10)
       }
-      if ((addr < 0) || (addr > 0xffff)) {
+      if (addr < 0 || addr > 0xffff) {
         throw IllegalStateException("Unable to relocate code outside 64k memory")
       }
       defaultCodePC = addr
@@ -73,7 +100,7 @@ class Assembler(private var labels: Labels, private var memory: Memory,
 
     param = param.replace("[ ]".toRegex(), "")
 
-    if (command === "DCB") {
+    if (command == "DCB") {
       return DCB(param)
     }
 
@@ -129,12 +156,35 @@ class Assembler(private var labels: Labels, private var memory: Memory,
         "not implemented") //To change body of created functions use File | Settings | File Templates.
   }
 
+  /** Common branch function for all branches (BCC, BCS, BEQ, BNE..) */
   private fun checkBranch(param: String, opcode: Int): Boolean {
-    throw UnsupportedOperationException(
-        "not implemented") //To change body of created functions use File | Settings | File Templates.
+    if (opcode == 0xff) {
+      return false
+    }
+
+    var addr = -1
+    if (param.matches("\\w+".toRegex())) {
+      addr = labels.get(param)
+    }
+    if (addr == -1) {
+      pushWord(0x00)
+      return false
+    }
+    pushByte(opcode)
+    if (addr < (defaultCodePC - 0x600)) {
+      // Backwards?
+      pushByte((0xff - ((defaultCodePC - 0x600) - addr)).and(0xff))
+      return true
+    }
+    pushByte((addr - (defaultCodePC - 0x600) - 1).and(0xff))
+    return true
   }
 
   private fun checkAbsolute(param: String, opcode: Int): Boolean {
+    if (opcode == 0xff) {
+      return false
+    }
+
     if (checkWordOperand(param, opcode, "^([\\w\\$]+)$")) {
       return true
     }
@@ -183,8 +233,8 @@ class Assembler(private var labels: Labels, private var memory: Memory,
     if (param.matches(regex)) {
       val finalParam = param.replace(",Y", "", true).replace(",X", "", true)
       pushByte(opcode)
-      if (labels.find(finalParam)) {
-        val addr = (labels.getPC(finalParam))
+      val addr = labels.get(finalParam)
+      if (addr != null) {
         if (addr < 0 || addr > 0xffff) {
           return false
         }
@@ -269,8 +319,8 @@ class Assembler(private var labels: Labels, private var memory: Memory,
       var label = param.replace("^#[<>](\\w+)$".toRegex(), "$1")
       var hilo = param.replace("^#([<>]).*$".toRegex(), "$1")
       pushByte(opcode)
-      if (labels.find(label)) {
-        var addr = labels.getPC(label)
+      val addr = labels.get(label)
+      if (addr != null) {
         when (hilo) {
           ">" -> {
             pushByte(addr.shr(8).and(0xFF))
@@ -296,7 +346,7 @@ class Assembler(private var labels: Labels, private var memory: Memory,
     var parameter = param
 
     if (parameter.matches("^\\w+$".toRegex())) {
-      var lookupVal = symbols.lookup(parameter) // Substitute symbol by actual value, then proceed
+      var lookupVal = symbols.get(parameter) // Substitute symbol by actual value, then proceed
       if (lookupVal != null) {
         parameter = lookupVal
       }
@@ -328,7 +378,7 @@ class Assembler(private var labels: Labels, private var memory: Memory,
     var parameter = param
 
     if (parameter.matches("^\\w+$".toRegex())) {
-      var lookupVal = symbols.lookup(parameter) // Substitute symbol by actual value, then proceed
+      var lookupVal = symbols.get(parameter) // Substitute symbol by actual value, then proceed
       if (lookupVal != null) {
         parameter = lookupVal
       }
@@ -368,7 +418,7 @@ class Assembler(private var labels: Labels, private var memory: Memory,
 
   private fun checkSingle(param: String, opcode: Int): Boolean {
     // Accumulator instructions are counted as single-byte opcodes
-    if (!param.equals("") && !param.equals("A")) { 
+    if (!param.equals("") && !param.equals("A")) {
       return false
     }
     pushByte(opcode)

app/src/main/kotlin/android/emu6502/Emulator.kt

@@ -1,8 +1,10 @@
 package android.emu6502
 
+import android.emu6502.instructions.Symbols
+
 final class Emulator {
   val display = Display()
   val memory = Memory(display)
   val cpu = CPU(memory)
-  val assembler = Assembler(Labels(), memory, Symbols())
+  val assembler = Assembler(memory, Symbols())
 }

app/src/main/kotlin/android/emu6502/Labels.kt

@@ -1,13 +1,39 @@
 package android.emu6502
 
-class Labels {
-  fun getPC(label: String): Int {
-    throw UnsupportedOperationException(
-        "not implemented") //To change body of created functions use File | Settings | File Templates.
+import android.emu6502.instructions.Symbols
+import java.util.*
+
+class Labels(private val assembler: Assembler, private val symbols: Symbols) : HashMap<String, Int>() {
+  private val labelIndex: ArrayList<String> = ArrayList()
+
+  fun indexLines(lines: List<String>) {
+    lines.forEach { line ->
+      indexLine(line)
+    }
   }
 
-  fun find(label: String): Boolean {
-    throw UnsupportedOperationException(
-        "not implemented") //To change body of created functions use File | Settings | File Templates.
+  fun get(label: String): Int {
+    return super.get(label) ?: -1
+  }
+
+  // Extract label if line contains one and calculate position in memory.
+  // Return false if label already exists.
+  private fun indexLine(input: String) {
+    // Figure out how many bytes this instruction takes
+    val currentPC = assembler.defaultCodePC;
+    // TODO: find a better way for Labels to have access to assembler
+    assembler.assembleLine(input);
+
+    // Find command or label
+    if (input.matches("^\\w+:".toRegex())) {
+      val label = input.replace("(^\\w+):.*$".toRegex(), "$1");
+
+      if (symbols.get(label) != null) {
+        throw RuntimeException(
+            "**Label " + label + "is already used as a symbol; please rename one of them**");
+      }
+
+      put(label, currentPC);
+    }
   }
 }

app/src/main/kotlin/android/emu6502/Symbols.kt

@@ -1,13 +0,0 @@
-package android.emu6502
-
-class Symbols {
-  private val table: Map<String, String> = emptyMap()
-
-  fun lookup(key: String): String? {
-    return null
-  }
-
-  fun add(key: String, value: String) {
-
-  }
-}

app/src/main/kotlin/android/emu6502/instructions/Symbols.kt

@@ -0,0 +1,6 @@
+package android.emu6502.instructions
+
+import java.util.*
+
+class Symbols : HashMap<String, String>() {
+}

app/src/test/java/android/emu6502/AssemblerTest.java

@@ -2,6 +2,9 @@ package android.emu6502;
 
 import com.google.common.collect.ImmutableList;
 
+import android.emu6502.instructions.Symbols;
+
+import org.junit.Before;
 import org.junit.Test;
 
 import java.util.List;
@@ -11,7 +14,13 @@ import static org.junit.Assert.assertThat;
 
 public class AssemblerTest {
 
-  @Test public void testAssembler() {
+  private Assembler assembler;
+
+  @Before public void setUp() {
+    assembler = new Assembler(new Memory(new Display()), new Symbols());
+  }
+
+  @Test public void testSimple() {
     List<String> lines = ImmutableList.of(
         "LDA #$01",
         "STA $0200",
@@ -19,8 +28,73 @@ public class AssemblerTest {
         "STA $0201",
         "LDA #$08",
         "STA $0202");
-    Assembler assembler = new Assembler(new Labels(), new Memory(new Display()), new Symbols());
     assembler.assembleCode(lines);
     assertThat(assembler.hexdump(), equalTo("0600: A9 01 8D 00 02 A9 05 8D 01 02 A9 08 8D 02 02"));
   }
+
+  @Test public void testWithComments() {
+    List<String> lines = ImmutableList.of(
+        "LDA #$c0  ;Load the hex value $c0 into the A register",
+        "TAX       ;Transfer the value in the A register to X",
+        "INX       ;Increment the value in the X register",
+        "ADC #$c4  ;Add the hex value $c4 to the A register",
+        "BRK       ;Break - we're done");
+    assembler.assembleCode(lines);
+    assertThat(assembler.hexdump(), equalTo("0600: A9 C0 AA E8 69 C4 00"));
+  }
+
+  @Test public void testBranchAndLabel() {
+    List<String> lines = ImmutableList.of(
+        "LDX #$08",
+        "decrement:",
+        "DEX",
+        "STX $0200",
+        "CPX #$03",
+        "BNE decrement",
+        "STX $0201",
+        "BRK");
+    assembler.assembleCode(lines);
+    assertThat(assembler.hexdump(), equalTo("0600: A2 08 CA 8E 00 02 E0 03 D0 F8 8E 01 02 00"));
+  }
+
+  @Test public void testRelative() {
+    List<String> lines = ImmutableList.of(
+        "LDA #$01",
+        "CMP #$02",
+        "BNE notequal",
+        "STA $22",
+        "notequal:",
+        "BRK");
+
+    assembler.assembleCode(lines);
+    assertThat(assembler.hexdump(), equalTo("0600: A9 01 C9 02 D0 02 85 22 00"));
+  }
+
+  @Test public void testIndirect() {
+    List<String> lines = ImmutableList.of(
+        "LDA #$01",
+        "STA $f0",
+        "LDA #$cc",
+        "STA $f1",
+        "JMP ($00f0) ;dereferences to $cc01");
+
+    assembler.assembleCode(lines);
+    assertThat(assembler.hexdump(), equalTo("0600: A9 01 85 F0 A9 CC 85 F1 6C F0 00"));
+  }
+
+  @Test public void testIndexedIndirect() {
+    List<String> lines = ImmutableList.of(
+        "LDX #$01",
+        "LDA #$05",
+        "STA $01",
+        "LDA #$06",
+        "STA $02",
+        "LDY #$0a",
+        "STY $0605",
+        "LDA ($00,X)");
+
+    assembler.assembleCode(lines);
+    assertThat(assembler.hexdump(),
+        equalTo("0600: A2 01 A9 05 85 01 A9 06 85 02 A0 0A 8C 05 06 A1 \n0610: 00"));
+  }
 }

app/src/test/java/android/emu6502/LabelsTest.java

@@ -0,0 +1,28 @@
+package android.emu6502;
+
+import android.emu6502.instructions.Symbols;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Collections;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+public class LabelsTest {
+
+  private Labels labels;
+  private Assembler assembler;
+
+  @Before public void setUp() {
+    Symbols symbols = new Symbols();
+    assembler = new Assembler(new Memory(new Display()), symbols);
+    labels = new Labels(assembler, symbols);
+  }
+
+  @Test public void testAddLabel() {
+    labels.indexLines(Collections.singletonList("test:"));
+    assertThat(labels.get("test"), equalTo(assembler.getDefaultCodePC()));
+  }
+}