Adds jump instructions

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

@@ -41,7 +41,10 @@ class CPU(val memory: Memory) {
       Pair(Instruction.ORA, ORA(this)),
       Pair(Instruction.CPX, CPX(this)),
       Pair(Instruction.BRK, BRK(this)),
-      Pair(Instruction.BNE, BNE(this))
+      Pair(Instruction.BNE, BNE(this)),
+      Pair(Instruction.JMP, JMP(this)),
+      Pair(Instruction.JSR, JSR(this)),
+      Pair(Instruction.RTS, RTS(this))
 //      Pair(Instruction.BPL, BPL(this)),
 //      Pair(Instruction.BMI, BMI(this)),
 //      Pair(Instruction.BVC, BVC(this)),
@@ -61,8 +64,6 @@ class CPU(val memory: Memory) {
 //      Pair(Instruction.CLD, CLD(this)),
 //      Pair(Instruction.SED, SED(this)),
 //      Pair(Instruction.INC, INC(this)),
-//      Pair(Instruction.JMP, JMP(this)),
-//      Pair(Instruction.JSR, JSR(this)),
 //      Pair(Instruction.LSR, LSR(this)),
 //      Pair(Instruction.NOP, NOP(this)),
 //      Pair(Instruction.TXA, TXA(this)),
@@ -73,7 +74,6 @@ class CPU(val memory: Memory) {
 //      Pair(Instruction.ROR, ROR(this)),
 //      Pair(Instruction.ROL, ROL(this)),
 //      Pair(Instruction.RTI, RTI(this)),
-//      Pair(Instruction.RTS, RTS(this)),
 //      Pair(Instruction.SBC, SBC(this)),
 //      Pair(Instruction.TXS, TXS(this)),
 //      Pair(Instruction.TSX, TSX(this)),
@@ -248,6 +248,24 @@ class CPU(val memory: Memory) {
     P = P.or(0x40)
   }
 
+  fun stackPush(value: Int) {
+    memory.set(SP.and(0xff) + 0x100, value.and(0xff))
+    SP--
+    if (SP < 0) {
+      SP = SP.and(0xff)
+      Log.i(TAG, "6502 Stack filled! Wrapping...")
+    }
+  }
+
+  fun stackPop(): Int {
+    SP++;
+    if (SP >= 0x100) {
+      SP = SP.and(0xff)
+      Log.i(TAG, "6502 Stack emptied! Wrapping...")
+    }
+    return memory.get(SP + 0x100)
+  }
+
   /**
    * http://nesdev.com/6502.txt
    * Returns the processor flags in the format SV-BDIZC

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

@@ -18,38 +18,62 @@ open class BaseInstruction(private val instruction: Instruction,
   }
 
   open fun immediate() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with immediate addressing")
   }
 
   open fun zeroPage() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with zeroPage addressing")
   }
 
   open fun zeroPageX() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with zeroPageX addressing")
   }
 
   open fun zeroPageY() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with zeroPageY addressing")
   }
 
   open fun absolute() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with absolute addressing")
   }
 
   open fun absoluteX() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with absoluteX addressing")
   }
 
   open fun absoluteY() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with absoluteY addressing")
   }
 
   open fun indirect() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with indirect addressing")
   }
 
   open fun indirectX() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with indirectX addressing")
   }
 
   open fun indirectY() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with indirectY addressing")
   }
 
   open fun single() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with single addressing")
   }
 
   open fun branch() {
+    throw IllegalStateException("Instruction " + javaClass.getSimpleName() + " not implemented" +
+        " with branch addressing")
   }
 }

app/src/main/kotlin/android/emu6502/instructions/impl/JMP.kt

@@ -0,0 +1,12 @@
+package android.emu6502.instructions.impl
+
+import android.emu6502.CPU
+import android.emu6502.instructions.BaseInstruction
+import android.emu6502.instructions.Instruction
+
+/** JuMP */
+class JMP(private val cpu: CPU) : BaseInstruction(Instruction.JMP, cpu.instructionList) {
+  override fun absolute() {
+    cpu.PC = cpu.popWord()
+  }
+}

app/src/main/kotlin/android/emu6502/instructions/impl/JSR.kt

@@ -0,0 +1,17 @@
+package android.emu6502.instructions.impl
+
+import android.emu6502.CPU
+import android.emu6502.instructions.BaseInstruction
+import android.emu6502.instructions.Instruction
+
+/** Jump to SubRoutine */
+class JSR(private val cpu: CPU) : BaseInstruction(Instruction.JSR, cpu.instructionList) {
+  override fun absolute() {
+    val addr = cpu.popWord()
+    val currAddr = cpu.PC - 1
+    cpu.stackPush(currAddr.shr(8).and(0xff))
+    cpu.stackPush(currAddr.and(0xff))
+    cpu.PC = addr
+  }
+}
+

app/src/main/kotlin/android/emu6502/instructions/impl/RTS.kt

@@ -0,0 +1,13 @@
+package android.emu6502.instructions.impl
+
+import android.emu6502.CPU
+import android.emu6502.instructions.BaseInstruction
+import android.emu6502.instructions.Instruction
+
+/** ReTurn from Subroutine */
+class RTS(private val cpu: CPU) : BaseInstruction(Instruction.RTS, cpu.instructionList) {
+  override fun single() {
+    cpu.PC = cpu.stackPop().or(cpu.stackPop().shl(8)) + 1
+  }
+}
+

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

@@ -1,9 +1,9 @@
 package android.emu6502;
 
-import com.google.common.collect.ImmutableList;
-
 import android.emu6502.instructions.Symbols;
 
+import com.google.common.collect.ImmutableList;
+
 import org.junit.Before;
 import org.junit.Test;
 
@@ -61,6 +61,7 @@ public class CPUTest {
   @Test public void testBranchAndLabel() {
     List<String> lines = ImmutableList.of(
         "LDX #$08",
+
         "decrement:",
         "DEX",
         "STX $0200",
@@ -77,4 +78,52 @@ public class CPUTest {
     assertThat(cpu.getPC(), equalTo(0x060e));
     assertThat(cpu.flags(), equalTo("00110011"));
   }
+
+  @Test public void testJump() {
+    List<String> lines = ImmutableList.of(
+        "LDA #$03",
+        "JMP there",
+        "BRK",
+        "BRK",
+        "BRK",
+
+        "there:",
+        "STA $0200");
+    assembler.assembleCode(lines);
+    cpu.execute();
+    assertThat(cpu.getA(), equalTo(0x03));
+    assertThat(cpu.getX(), equalTo(0x00));
+    assertThat(cpu.getY(), equalTo(0x00));
+    assertThat(cpu.getSP(), equalTo(0xFF));
+    assertThat(cpu.getPC(), equalTo(0x060c));
+    assertThat(cpu.flags(), equalTo("00110000"));
+  }
+
+  @Test public void testJumpToSubroutines() {
+    List<String> lines = ImmutableList.of(
+        "JSR init",
+        "JSR loop",
+        "JSR end",
+
+        "init:",
+        "LDX #$00",
+        "RTS",
+
+        "loop:",
+        "INX",
+        "CPX #$05",
+        "BNE loop",
+        "RTS",
+
+        "end:",
+        "BRK");
+    assembler.assembleCode(lines);
+    cpu.execute();
+    assertThat(cpu.getA(), equalTo(0x00));
+    assertThat(cpu.getX(), equalTo(0x05));
+    assertThat(cpu.getY(), equalTo(0x00));
+    assertThat(cpu.getSP(), equalTo(0xFD));
+    assertThat(cpu.getPC(), equalTo(0x0613));
+    assertThat(cpu.flags(), equalTo("00110011"));
+  }
 }