diff --git a/src/nes/cpu.rs b/src/nes/cpu.rs
index e40cdfa..68247aa 100644
--- a/src/nes/cpu.rs
+++ b/src/nes/cpu.rs
@@ -65,7 +65,7 @@ impl Clockable for CPU {
         if self.cycles_ahead == 0 {
             let opcode = self.readb_pc(bus);
             self.curr_op = opcode;
-            let instruction = Instruction::decode_op(opcode).unwrap();  // TODO error handling
+            let instruction = Instruction::decode_op(opcode);
             info!("{:#06X}  {:02X} {}          A:{:02X} X:{:02X} Y:{:02X} P:{:02X} SP:{:02X} CYC:{}",
                 self.regs.pc-1, opcode, instruction.operation,
                 self.regs.a, self.regs.x, self.regs.y, self.regs.flags, self.regs.sp, self.cycles);
@@ -234,6 +234,7 @@ impl CPU {
             Operation::INC => self.op_INC(bus, value),
             Operation::INX => self.op_INX(),
             Operation::INY => self.op_INY(),
+            Operation::ISB => self.op_ISB(bus, value),
             Operation::JMP => self.op_JMP(value),
             Operation::JSR => self.op_JSR(bus, value),
             Operation::LAX => self.op_LAX(bus, value),
@@ -256,6 +257,7 @@ impl CPU {
             Operation::SEC => self.op_SEC(),
             Operation::SED => self.op_SED(),
             Operation::SEI => self.op_SEI(),
+            Operation::SLO => self.op_SLO(bus, value),
             Operation::STA => self.op_STA(bus, value),
             Operation::STX => self.op_STX(bus, value),
             Operation::STY => self.op_STY(bus, value),
@@ -265,6 +267,11 @@ impl CPU {
             Operation::TXA => self.op_TXA(),
             Operation::TXS => self.op_TXS(),
             Operation::TYA => self.op_TYA(),
+            _ => { 
+                // OP not implemented. do nothing
+                warn!("Operation not implemented: {:?}", i.operation);
+                false
+            }
         };
 
         if page_cross && extra_cycle_on_page_cross {
@@ -448,7 +455,7 @@ impl CPU {
     // Negative bit is set
     fn op_ASL<T: Memory>(&mut self, bus: &mut T, addr: Addr) -> bool {
         // LSR works on memory or A. We can differenciate by the addr mode
-        let addr_mode = &Instruction::decode_op(self.curr_op).unwrap().addr_mode;
+        let addr_mode = &Instruction::decode_op(self.curr_op).addr_mode;
         let val = if *addr_mode == AddrMode::IMP {
             self.regs.a
         } else {
@@ -726,6 +733,13 @@ impl CPU {
         false
     }
 
+    // Unofficial opcode: INC, then SBC
+    fn op_ISB<T: Memory>(&mut self, bus: &mut T, addr: Addr) -> bool {
+        self.op_INC(bus, addr);
+        self.op_SBC(bus, addr);
+        false
+    }
+
     // Jump to address (set pc)
     fn op_JMP(&mut self, addr: Addr) -> bool {
         self.jump(addr);
@@ -780,7 +794,7 @@ impl CPU {
     // that was in bit 0 is shifted into the carry flag. Bit 7 is set to zero.
     fn op_LSR<T: Memory>(&mut self, bus: &mut T, addr: Addr) -> bool {
         // LSR works on memory or A. We can differenciate by the addr mode
-        let addr_mode = &Instruction::decode_op(self.curr_op).unwrap().addr_mode;
+        let addr_mode = &Instruction::decode_op(self.curr_op).addr_mode;
         let val = if *addr_mode == AddrMode::IMP {
             self.regs.a as Word
         } else {
@@ -854,7 +868,7 @@ impl CPU {
     // filled with the current value of the carry flag whilst the old bit 7
     // becomes the new carry flag value.
     fn op_ROL<T: Memory>(&mut self, bus: &mut T, addr: Addr) -> bool {
-        let addr_mode = &Instruction::decode_op(self.curr_op).unwrap().addr_mode;
+        let addr_mode = &Instruction::decode_op(self.curr_op).addr_mode;
         let val = if *addr_mode == AddrMode::IMP {
             self.regs.a as Word
         } else {
@@ -878,7 +892,7 @@ impl CPU {
     // filled with the current value of the carry flag whilst the old bit 0
     // becomes the new carry flag value.
     fn op_ROR<T: Memory>(&mut self, bus: &mut T, addr: Addr) -> bool {
-        let addr_mode = &Instruction::decode_op(self.curr_op).unwrap().addr_mode;
+        let addr_mode = &Instruction::decode_op(self.curr_op).addr_mode;
         let val = if *addr_mode == AddrMode::IMP {
             self.regs.a as Word
         } else {
@@ -982,6 +996,13 @@ impl CPU {
         false
     }
 
+    // Unofficial opcode: ASL then ORA
+    fn op_SLO<T: Memory>(&mut self, bus: &mut T, addr: Word) -> bool {
+        self.op_ASL(bus, addr);
+        self.op_ORA(bus, addr);
+        false
+    }
+
     // Push A reg to memory
     fn op_STA<T: Memory>(&mut self, bus: &mut T, addr: Word) -> bool {
         self.writeb(bus, addr, self.regs.a);
diff --git a/src/nes/cpu/instructions.rs b/src/nes/cpu/instructions.rs
index afb2a11..b943843 100644
--- a/src/nes/cpu/instructions.rs
+++ b/src/nes/cpu/instructions.rs
@@ -30,8 +30,13 @@ impl fmt::Display for AddrMode {
 #[derive(Debug,PartialEq)]
 pub enum Operation {
     ADC,
+    AHX,
+    ALR,
+    ANC,
     AND,
+    ARR,
     ASL,
+    AXS,
     BCC,
     BCS,
     BEQ,
@@ -57,8 +62,11 @@ pub enum Operation {
     INC,
     INX,
     INY,
+    ISB,
     JMP,
     JSR,
+    KIL,
+    LAS,
     LAX,
     LDA,
     LDX,
@@ -70,8 +78,10 @@ pub enum Operation {
     PHP,
     PLA,
     PLP,
+    RLA,
     ROL,
     ROR,
+    RRA,
     RTI,
     RTS,
     SAX,
@@ -79,15 +89,21 @@ pub enum Operation {
     SEC,
     SED,
     SEI,
+    SHX,
+    SHY,
+    SLO,
+    SRE,
     STA,
     STX,
     STY,
+    TAS,
     TAX,
     TAY,
     TSX,
     TXA,
     TXS,
     TYA,
+    XAA,
 }
 
 impl fmt::Display for Operation {
@@ -99,100 +115,140 @@ impl fmt::Display for Operation {
 static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     // 0x00
     0x00u8 => Instruction { opcode: 0x00, addr_mode: AddrMode::IMP, operation: Operation::BRK, cycles: [7, 0] }, 
-    0x01u8 => Instruction { opcode: 0x01, addr_mode: AddrMode::IZX, operation: Operation::ORA, cycles: [6, 0] },
+    0x01u8 => Instruction { opcode: 0x01, addr_mode: AddrMode::IZX, operation: Operation::ORA, cycles: [6, 0] }, 
+    0x02u8 => Instruction { opcode: 0x02, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x03u8 => Instruction { opcode: 0x03, addr_mode: AddrMode::IZX, operation: Operation::SLO, cycles: [8, 0] }, 
     0x04u8 => Instruction { opcode: 0x04, addr_mode: AddrMode::ZP0, operation: Operation::NOP, cycles: [3, 0] },
     0x05u8 => Instruction { opcode: 0x05, addr_mode: AddrMode::ZP0, operation: Operation::ORA, cycles: [3, 0] }, 
     0x06u8 => Instruction { opcode: 0x06, addr_mode: AddrMode::ZP0, operation: Operation::ASL, cycles: [5, 0] }, 
+    0x07u8 => Instruction { opcode: 0x07, addr_mode: AddrMode::ZP0, operation: Operation::SLO, cycles: [5, 0] }, 
     0x08u8 => Instruction { opcode: 0x08, addr_mode: AddrMode::IMP, operation: Operation::PHP, cycles: [3, 0] }, 
     0x09u8 => Instruction { opcode: 0x09, addr_mode: AddrMode::IMM, operation: Operation::ORA, cycles: [2, 0] }, 
     0x0au8 => Instruction { opcode: 0x0a, addr_mode: AddrMode::IMP, operation: Operation::ASL, cycles: [2, 0] },
+    0x0bu8 => Instruction { opcode: 0x0b, addr_mode: AddrMode::IMM, operation: Operation::ANC, cycles: [2, 0] },
     0x0cu8 => Instruction { opcode: 0x0c, addr_mode: AddrMode::ABS, operation: Operation::NOP, cycles: [4, 0] },
     0x0du8 => Instruction { opcode: 0x0d, addr_mode: AddrMode::ABS, operation: Operation::ORA, cycles: [4, 0] }, 
     0x0eu8 => Instruction { opcode: 0x0e, addr_mode: AddrMode::ABS, operation: Operation::ASL, cycles: [6, 0] }, 
+    0x0fu8 => Instruction { opcode: 0x0f, addr_mode: AddrMode::ABS, operation: Operation::SLO, cycles: [6, 0] }, 
     // 0x10
     0x10u8 => Instruction { opcode: 0x10, addr_mode: AddrMode::REL, operation: Operation::BPL, cycles: [2, 0] }, 
-    0x11u8 => Instruction { opcode: 0x11, addr_mode: AddrMode::IZY, operation: Operation::ORA, cycles: [5, 0] },
+    0x11u8 => Instruction { opcode: 0x11, addr_mode: AddrMode::IZY, operation: Operation::ORA, cycles: [5, 0] }, 
+    0x12u8 => Instruction { opcode: 0x12, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x13u8 => Instruction { opcode: 0x13, addr_mode: AddrMode::IZY, operation: Operation::SLO, cycles: [8, 0] }, 
     0x14u8 => Instruction { opcode: 0x14, addr_mode: AddrMode::ZPX, operation: Operation::NOP, cycles: [4, 0] },
     0x15u8 => Instruction { opcode: 0x15, addr_mode: AddrMode::ZPX, operation: Operation::ORA, cycles: [4, 0] }, 
     0x16u8 => Instruction { opcode: 0x16, addr_mode: AddrMode::ZPX, operation: Operation::ASL, cycles: [6, 0] }, 
+    0x17u8 => Instruction { opcode: 0x17, addr_mode: AddrMode::ZPX, operation: Operation::SLO, cycles: [6, 0] }, 
     0x18u8 => Instruction { opcode: 0x18, addr_mode: AddrMode::IMP, operation: Operation::CLC, cycles: [2, 0] }, 
     0x19u8 => Instruction { opcode: 0x19, addr_mode: AddrMode::ABY, operation: Operation::ORA, cycles: [4, 0] },
     0x1au8 => Instruction { opcode: 0x1a, addr_mode: AddrMode::IMP, operation: Operation::NOP, cycles: [2, 0] },
+    0x1bu8 => Instruction { opcode: 0x1b, addr_mode: AddrMode::ABY, operation: Operation::SLO, cycles: [7, 0] }, 
     0x1cu8 => Instruction { opcode: 0x1c, addr_mode: AddrMode::ABX, operation: Operation::NOP, cycles: [4, 0] },
     0x1du8 => Instruction { opcode: 0x1d, addr_mode: AddrMode::ABX, operation: Operation::ORA, cycles: [4, 0] }, 
     0x1eu8 => Instruction { opcode: 0x1e, addr_mode: AddrMode::ABX, operation: Operation::ASL, cycles: [7, 0] }, 
+    0x1fu8 => Instruction { opcode: 0x1f, addr_mode: AddrMode::ABX, operation: Operation::SLO, cycles: [7, 0] }, 
     // 0x20
     0x20u8 => Instruction { opcode: 0x20, addr_mode: AddrMode::ABS, operation: Operation::JSR, cycles: [6, 0] }, 
     0x21u8 => Instruction { opcode: 0x21, addr_mode: AddrMode::IZX, operation: Operation::AND, cycles: [6, 0] }, 
+    0x22u8 => Instruction { opcode: 0x22, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x23u8 => Instruction { opcode: 0x23, addr_mode: AddrMode::IZX, operation: Operation::RLA, cycles: [8, 0] }, 
     0x24u8 => Instruction { opcode: 0x24, addr_mode: AddrMode::ZP0, operation: Operation::BIT, cycles: [3, 0] }, 
     0x25u8 => Instruction { opcode: 0x25, addr_mode: AddrMode::ZP0, operation: Operation::AND, cycles: [3, 0] }, 
     0x26u8 => Instruction { opcode: 0x26, addr_mode: AddrMode::ZP0, operation: Operation::ROL, cycles: [5, 0] }, 
+    0x27u8 => Instruction { opcode: 0x27, addr_mode: AddrMode::ZP0, operation: Operation::RLA, cycles: [5, 0] }, 
     0x28u8 => Instruction { opcode: 0x28, addr_mode: AddrMode::IMP, operation: Operation::PLP, cycles: [4, 0] }, 
     0x29u8 => Instruction { opcode: 0x29, addr_mode: AddrMode::IMM, operation: Operation::AND, cycles: [2, 0] }, 
     0x2au8 => Instruction { opcode: 0x2a, addr_mode: AddrMode::IMP, operation: Operation::ROL, cycles: [2, 0] }, 
+    0x2bu8 => Instruction { opcode: 0x2b, addr_mode: AddrMode::IMM, operation: Operation::ANC, cycles: [2, 0] }, 
     0x2cu8 => Instruction { opcode: 0x2c, addr_mode: AddrMode::ABS, operation: Operation::BIT, cycles: [4, 0] }, 
     0x2du8 => Instruction { opcode: 0x2d, addr_mode: AddrMode::ABS, operation: Operation::AND, cycles: [4, 0] }, 
     0x2eu8 => Instruction { opcode: 0x2e, addr_mode: AddrMode::ABS, operation: Operation::ROL, cycles: [6, 0] }, 
+    0x2fu8 => Instruction { opcode: 0x2f, addr_mode: AddrMode::ABS, operation: Operation::RLA, cycles: [6, 0] }, 
     // 0x30
     0x30u8 => Instruction { opcode: 0x30, addr_mode: AddrMode::REL, operation: Operation::BMI, cycles: [2, 0] }, 
-    0x31u8 => Instruction { opcode: 0x31, addr_mode: AddrMode::IZY, operation: Operation::AND, cycles: [5, 0] },
+    0x31u8 => Instruction { opcode: 0x31, addr_mode: AddrMode::IZY, operation: Operation::AND, cycles: [5, 0] }, 
+    0x32u8 => Instruction { opcode: 0x32, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x33u8 => Instruction { opcode: 0x33, addr_mode: AddrMode::IZY, operation: Operation::RLA, cycles: [8, 0] },
     0x34u8 => Instruction { opcode: 0x34, addr_mode: AddrMode::ZPX, operation: Operation::NOP, cycles: [4, 0] },
     0x35u8 => Instruction { opcode: 0x35, addr_mode: AddrMode::ZPX, operation: Operation::AND, cycles: [4, 0] }, 
-    0x36u8 => Instruction { opcode: 0x36, addr_mode: AddrMode::ZPX, operation: Operation::ROL, cycles: [6, 0] }, 
+    0x36u8 => Instruction { opcode: 0x36, addr_mode: AddrMode::ZPX, operation: Operation::ROL, cycles: [6, 0] },
+    0x37u8 => Instruction { opcode: 0x37, addr_mode: AddrMode::ZPX, operation: Operation::RLA, cycles: [6, 0] },
     0x38u8 => Instruction { opcode: 0x38, addr_mode: AddrMode::IMP, operation: Operation::SEC, cycles: [2, 0] }, 
     0x39u8 => Instruction { opcode: 0x39, addr_mode: AddrMode::ABY, operation: Operation::AND, cycles: [4, 0] },
     0x3au8 => Instruction { opcode: 0x3a, addr_mode: AddrMode::IMP, operation: Operation::NOP, cycles: [2, 0] },
+    0x3bu8 => Instruction { opcode: 0x3b, addr_mode: AddrMode::ABY, operation: Operation::RLA, cycles: [7, 0] },
     0x3cu8 => Instruction { opcode: 0x3c, addr_mode: AddrMode::ABX, operation: Operation::NOP, cycles: [4, 0] },
     0x3du8 => Instruction { opcode: 0x3d, addr_mode: AddrMode::ABX, operation: Operation::AND, cycles: [4, 0] }, 
     0x3eu8 => Instruction { opcode: 0x3e, addr_mode: AddrMode::ABX, operation: Operation::ROL, cycles: [7, 0] }, 
+    0x3fu8 => Instruction { opcode: 0x3f, addr_mode: AddrMode::ABX, operation: Operation::RLA, cycles: [7, 0] }, 
     // 0x40
     0x40u8 => Instruction { opcode: 0x40, addr_mode: AddrMode::IMP, operation: Operation::RTI, cycles: [6, 0] }, 
-    0x41u8 => Instruction { opcode: 0x41, addr_mode: AddrMode::IZX, operation: Operation::EOR, cycles: [6, 0] }, 
+    0x41u8 => Instruction { opcode: 0x41, addr_mode: AddrMode::IZX, operation: Operation::EOR, cycles: [6, 0] },  
+    0x42u8 => Instruction { opcode: 0x42, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x43u8 => Instruction { opcode: 0x43, addr_mode: AddrMode::IZX, operation: Operation::SRE, cycles: [8, 0] }, 
     0x44u8 => Instruction { opcode: 0x44, addr_mode: AddrMode::ZP0, operation: Operation::NOP, cycles: [3, 0] },
     0x45u8 => Instruction { opcode: 0x45, addr_mode: AddrMode::ZP0, operation: Operation::EOR, cycles: [3, 0] }, 
     0x46u8 => Instruction { opcode: 0x46, addr_mode: AddrMode::ZP0, operation: Operation::LSR, cycles: [5, 0] }, 
+    0x47u8 => Instruction { opcode: 0x47, addr_mode: AddrMode::ZP0, operation: Operation::SRE, cycles: [5, 0] }, 
     0x48u8 => Instruction { opcode: 0x48, addr_mode: AddrMode::IMP, operation: Operation::PHA, cycles: [3, 0] }, 
     0x49u8 => Instruction { opcode: 0x49, addr_mode: AddrMode::IMM, operation: Operation::EOR, cycles: [2, 0] }, 
     0x4au8 => Instruction { opcode: 0x4a, addr_mode: AddrMode::IMP, operation: Operation::LSR, cycles: [2, 0] }, 
+    0x4bu8 => Instruction { opcode: 0x4b, addr_mode: AddrMode::IMM, operation: Operation::ALR, cycles: [2, 0] }, 
     0x4cu8 => Instruction { opcode: 0x4c, addr_mode: AddrMode::ABS, operation: Operation::JMP, cycles: [3, 0] }, 
     0x4du8 => Instruction { opcode: 0x4d, addr_mode: AddrMode::ABS, operation: Operation::EOR, cycles: [4, 0] }, 
     0x4eu8 => Instruction { opcode: 0x4e, addr_mode: AddrMode::ABS, operation: Operation::LSR, cycles: [6, 0] }, 
+    0x4fu8 => Instruction { opcode: 0x4f, addr_mode: AddrMode::ABS, operation: Operation::SRE, cycles: [6, 0] }, 
     // 0x50
     0x50u8 => Instruction { opcode: 0x50, addr_mode: AddrMode::REL, operation: Operation::BVC, cycles: [2, 0] }, 
     0x51u8 => Instruction { opcode: 0x51, addr_mode: AddrMode::IZY, operation: Operation::EOR, cycles: [5, 0] }, 
+    0x52u8 => Instruction { opcode: 0x52, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] }, 
+    0x53u8 => Instruction { opcode: 0x53, addr_mode: AddrMode::IZY, operation: Operation::SRE, cycles: [8, 0] }, 
     0x54u8 => Instruction { opcode: 0x54, addr_mode: AddrMode::ZPX, operation: Operation::NOP, cycles: [4, 0] },
     0x55u8 => Instruction { opcode: 0x55, addr_mode: AddrMode::ZPX, operation: Operation::EOR, cycles: [4, 0] }, 
     0x56u8 => Instruction { opcode: 0x56, addr_mode: AddrMode::ZPX, operation: Operation::LSR, cycles: [6, 0] }, 
+    0x57u8 => Instruction { opcode: 0x57, addr_mode: AddrMode::ZPX, operation: Operation::SRE, cycles: [6, 0] }, 
     0x58u8 => Instruction { opcode: 0x58, addr_mode: AddrMode::IMP, operation: Operation::CLI, cycles: [2, 0] }, 
     0x59u8 => Instruction { opcode: 0x59, addr_mode: AddrMode::ABY, operation: Operation::EOR, cycles: [4, 0] }, 
     0x5au8 => Instruction { opcode: 0x5a, addr_mode: AddrMode::IMP, operation: Operation::NOP, cycles: [2, 0] },
+    0x5bu8 => Instruction { opcode: 0x5b, addr_mode: AddrMode::ABY, operation: Operation::SRE, cycles: [7, 0] },
     0x5cu8 => Instruction { opcode: 0x5c, addr_mode: AddrMode::ABX, operation: Operation::NOP, cycles: [4, 0] },
     0x5du8 => Instruction { opcode: 0x5d, addr_mode: AddrMode::ABX, operation: Operation::EOR, cycles: [4, 0] }, 
     0x5eu8 => Instruction { opcode: 0x5e, addr_mode: AddrMode::ABX, operation: Operation::LSR, cycles: [7, 0] }, 
+    0x5fu8 => Instruction { opcode: 0x5f, addr_mode: AddrMode::ABX, operation: Operation::SRE, cycles: [7, 0] }, 
     // 0x60
     0x60u8 => Instruction { opcode: 0x60, addr_mode: AddrMode::IMP, operation: Operation::RTS, cycles: [6, 0] }, 
     0x61u8 => Instruction { opcode: 0x61, addr_mode: AddrMode::IZX, operation: Operation::ADC, cycles: [6, 0] }, 
+    0x62u8 => Instruction { opcode: 0x62, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x63u8 => Instruction { opcode: 0x63, addr_mode: AddrMode::IZX, operation: Operation::RRA, cycles: [8, 0] }, 
     0x64u8 => Instruction { opcode: 0x64, addr_mode: AddrMode::ZP0, operation: Operation::NOP, cycles: [3, 0] },
     0x65u8 => Instruction { opcode: 0x65, addr_mode: AddrMode::ZP0, operation: Operation::ADC, cycles: [3, 0] }, 
-    0x66u8 => Instruction { opcode: 0x66, addr_mode: AddrMode::ZP0, operation: Operation::ROR, cycles: [5, 0] }, 
+    0x66u8 => Instruction { opcode: 0x66, addr_mode: AddrMode::ZP0, operation: Operation::ROR, cycles: [5, 0] },
+    0x67u8 => Instruction { opcode: 0x67, addr_mode: AddrMode::ZP0, operation: Operation::RRA, cycles: [5, 0] }, 
     0x68u8 => Instruction { opcode: 0x68, addr_mode: AddrMode::IMP, operation: Operation::PLA, cycles: [4, 0] }, 
     0x69u8 => Instruction { opcode: 0x69, addr_mode: AddrMode::IMM, operation: Operation::ADC, cycles: [2, 0] }, 
     0x6au8 => Instruction { opcode: 0x6a, addr_mode: AddrMode::IMP, operation: Operation::ROR, cycles: [2, 0] }, 
+    0x6bu8 => Instruction { opcode: 0x6b, addr_mode: AddrMode::IMM, operation: Operation::ARR, cycles: [2, 0] }, 
     0x6cu8 => Instruction { opcode: 0x6c, addr_mode: AddrMode::IND, operation: Operation::JMP, cycles: [5, 0] }, 
     0x6du8 => Instruction { opcode: 0x6d, addr_mode: AddrMode::ABS, operation: Operation::ADC, cycles: [4, 0] }, 
     0x6eu8 => Instruction { opcode: 0x6e, addr_mode: AddrMode::ABS, operation: Operation::ROR, cycles: [6, 0] }, 
+    0x6fu8 => Instruction { opcode: 0x6f, addr_mode: AddrMode::ABS, operation: Operation::RRA, cycles: [6, 0] }, 
     // 0x70
     0x70u8 => Instruction { opcode: 0x70, addr_mode: AddrMode::REL, operation: Operation::BVS, cycles: [2, 0] }, 
-    0x71u8 => Instruction { opcode: 0x71, addr_mode: AddrMode::IZY, operation: Operation::ADC, cycles: [5, 0] }, 
+    0x71u8 => Instruction { opcode: 0x71, addr_mode: AddrMode::IZY, operation: Operation::ADC, cycles: [5, 0] },
+    0x72u8 => Instruction { opcode: 0x72, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] }, 
+    0x73u8 => Instruction { opcode: 0x73, addr_mode: AddrMode::IZY, operation: Operation::RRA, cycles: [8, 0] }, 
     0x74u8 => Instruction { opcode: 0x74, addr_mode: AddrMode::ZPX, operation: Operation::NOP, cycles: [4, 0] },
     0x75u8 => Instruction { opcode: 0x75, addr_mode: AddrMode::ZPX, operation: Operation::ADC, cycles: [4, 0] }, 
     0x76u8 => Instruction { opcode: 0x76, addr_mode: AddrMode::ZPX, operation: Operation::ROR, cycles: [6, 0] }, 
+    0x77u8 => Instruction { opcode: 0x77, addr_mode: AddrMode::ZPX, operation: Operation::RRA, cycles: [6, 0] }, 
     0x78u8 => Instruction { opcode: 0x78, addr_mode: AddrMode::IMP, operation: Operation::SEI, cycles: [2, 0] }, 
     0x79u8 => Instruction { opcode: 0x79, addr_mode: AddrMode::ABY, operation: Operation::ADC, cycles: [4, 0] }, 
     0x7au8 => Instruction { opcode: 0x7a, addr_mode: AddrMode::IMP, operation: Operation::NOP, cycles: [2, 0] },
+    0x7bu8 => Instruction { opcode: 0x7b, addr_mode: AddrMode::ABY, operation: Operation::RRA, cycles: [7, 0] },
     0x7cu8 => Instruction { opcode: 0x7c, addr_mode: AddrMode::ABX, operation: Operation::NOP, cycles: [4, 0] },
     0x7du8 => Instruction { opcode: 0x7d, addr_mode: AddrMode::ABX, operation: Operation::ADC, cycles: [4, 0] }, 
     0x7eu8 => Instruction { opcode: 0x7e, addr_mode: AddrMode::ABX, operation: Operation::ROR, cycles: [7, 0] }, 
+    0x7fu8 => Instruction { opcode: 0x7f, addr_mode: AddrMode::ABX, operation: Operation::RRA, cycles: [7, 0] },
     // 0x80
     0x80u8 => Instruction { opcode: 0x80, addr_mode: AddrMode::IMM, operation: Operation::NOP, cycles: [2, 0] },
     0x81u8 => Instruction { opcode: 0x81, addr_mode: AddrMode::IZX, operation: Operation::STA, cycles: [6, 0] }, 
@@ -205,13 +261,16 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0x88u8 => Instruction { opcode: 0x88, addr_mode: AddrMode::IMP, operation: Operation::DEY, cycles: [2, 0] }, 
     0x89u8 => Instruction { opcode: 0x89, addr_mode: AddrMode::IMM, operation: Operation::NOP, cycles: [2, 0] },
     0x8au8 => Instruction { opcode: 0x8a, addr_mode: AddrMode::IMP, operation: Operation::TXA, cycles: [2, 0] }, 
+    0x8bu8 => Instruction { opcode: 0x8b, addr_mode: AddrMode::IMM, operation: Operation::XAA, cycles: [2, 0] }, 
     0x8cu8 => Instruction { opcode: 0x8c, addr_mode: AddrMode::ABS, operation: Operation::STY, cycles: [4, 0] }, 
     0x8du8 => Instruction { opcode: 0x8d, addr_mode: AddrMode::ABS, operation: Operation::STA, cycles: [4, 0] }, 
     0x8eu8 => Instruction { opcode: 0x8e, addr_mode: AddrMode::ABS, operation: Operation::STX, cycles: [4, 0] }, 
     0x8fu8 => Instruction { opcode: 0x8f, addr_mode: AddrMode::ABS, operation: Operation::SAX, cycles: [4, 0] },
     // 0x90
     0x90u8 => Instruction { opcode: 0x90, addr_mode: AddrMode::REL, operation: Operation::BCC, cycles: [2, 0] }, 
-    0x91u8 => Instruction { opcode: 0x91, addr_mode: AddrMode::IZY, operation: Operation::STA, cycles: [6, 0] }, 
+    0x91u8 => Instruction { opcode: 0x91, addr_mode: AddrMode::IZY, operation: Operation::STA, cycles: [6, 0] },
+    0x92u8 => Instruction { opcode: 0x92, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] },
+    0x93u8 => Instruction { opcode: 0x93, addr_mode: AddrMode::IZY, operation: Operation::AHX, cycles: [6, 0] }, 
     0x94u8 => Instruction { opcode: 0x94, addr_mode: AddrMode::ZPX, operation: Operation::STY, cycles: [4, 0] }, 
     0x95u8 => Instruction { opcode: 0x95, addr_mode: AddrMode::ZPX, operation: Operation::STA, cycles: [4, 0] }, 
     0x96u8 => Instruction { opcode: 0x96, addr_mode: AddrMode::ZPY, operation: Operation::STX, cycles: [4, 0] }, 
@@ -219,7 +278,11 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0x98u8 => Instruction { opcode: 0x98, addr_mode: AddrMode::IMP, operation: Operation::TYA, cycles: [2, 0] }, 
     0x99u8 => Instruction { opcode: 0x99, addr_mode: AddrMode::ABY, operation: Operation::STA, cycles: [5, 0] }, 
     0x9au8 => Instruction { opcode: 0x9a, addr_mode: AddrMode::IMP, operation: Operation::TXS, cycles: [2, 0] }, 
+    0x9bu8 => Instruction { opcode: 0x9b, addr_mode: AddrMode::ABY, operation: Operation::TAS, cycles: [5, 0] }, 
+    0x9cu8 => Instruction { opcode: 0x9c, addr_mode: AddrMode::ABX, operation: Operation::SHY, cycles: [5, 0] }, 
     0x9du8 => Instruction { opcode: 0x9d, addr_mode: AddrMode::ABX, operation: Operation::STA, cycles: [5, 0] }, 
+    0x9eu8 => Instruction { opcode: 0x9e, addr_mode: AddrMode::ABY, operation: Operation::SHX, cycles: [5, 0] }, 
+    0x9fu8 => Instruction { opcode: 0x9f, addr_mode: AddrMode::ABY, operation: Operation::AHX, cycles: [5, 0] }, 
     // 0xa0
     0xa0u8 => Instruction { opcode: 0xa0, addr_mode: AddrMode::IMM, operation: Operation::LDY, cycles: [2, 0] }, 
     0xa1u8 => Instruction { opcode: 0xa1, addr_mode: AddrMode::IZX, operation: Operation::LDA, cycles: [6, 0] }, 
@@ -232,6 +295,7 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0xa8u8 => Instruction { opcode: 0xa8, addr_mode: AddrMode::IMP, operation: Operation::TAY, cycles: [2, 0] }, 
     0xa9u8 => Instruction { opcode: 0xa9, addr_mode: AddrMode::IMM, operation: Operation::LDA, cycles: [2, 0] }, 
     0xaau8 => Instruction { opcode: 0xaa, addr_mode: AddrMode::IMP, operation: Operation::TAX, cycles: [2, 0] }, 
+    0xabu8 => Instruction { opcode: 0xab, addr_mode: AddrMode::IMM, operation: Operation::LAX, cycles: [2, 0] }, 
     0xacu8 => Instruction { opcode: 0xac, addr_mode: AddrMode::ABS, operation: Operation::LDY, cycles: [4, 0] }, 
     0xadu8 => Instruction { opcode: 0xad, addr_mode: AddrMode::ABS, operation: Operation::LDA, cycles: [4, 0] }, 
     0xaeu8 => Instruction { opcode: 0xae, addr_mode: AddrMode::ABS, operation: Operation::LDX, cycles: [4, 0] }, 
@@ -239,6 +303,7 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     // 0xb0
     0xb0u8 => Instruction { opcode: 0xb0, addr_mode: AddrMode::REL, operation: Operation::BCS, cycles: [2, 0] }, 
     0xb1u8 => Instruction { opcode: 0xb1, addr_mode: AddrMode::IZY, operation: Operation::LDA, cycles: [5, 0] }, 
+    0xb2u8 => Instruction { opcode: 0xb2, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] }, 
     0xb3u8 => Instruction { opcode: 0xb3, addr_mode: AddrMode::IZY, operation: Operation::LAX, cycles: [5, 0] },
     0xb4u8 => Instruction { opcode: 0xb4, addr_mode: AddrMode::ZPX, operation: Operation::LDY, cycles: [4, 0] }, 
     0xb5u8 => Instruction { opcode: 0xb5, addr_mode: AddrMode::ZPX, operation: Operation::LDA, cycles: [4, 0] }, 
@@ -247,6 +312,7 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0xb8u8 => Instruction { opcode: 0xb8, addr_mode: AddrMode::IMP, operation: Operation::CLV, cycles: [2, 0] }, 
     0xb9u8 => Instruction { opcode: 0xb9, addr_mode: AddrMode::ABY, operation: Operation::LDA, cycles: [4, 0] }, 
     0xbau8 => Instruction { opcode: 0xba, addr_mode: AddrMode::IMP, operation: Operation::TSX, cycles: [2, 0] }, 
+    0xbbu8 => Instruction { opcode: 0xbb, addr_mode: AddrMode::ABY, operation: Operation::LAS, cycles: [4, 0] }, 
     0xbcu8 => Instruction { opcode: 0xbc, addr_mode: AddrMode::ABX, operation: Operation::LDY, cycles: [4, 0] }, 
     0xbdu8 => Instruction { opcode: 0xbd, addr_mode: AddrMode::ABX, operation: Operation::LDA, cycles: [4, 0] }, 
     0xbeu8 => Instruction { opcode: 0xbe, addr_mode: AddrMode::ABY, operation: Operation::LDX, cycles: [4, 0] }, 
@@ -263,14 +329,16 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0xc8u8 => Instruction { opcode: 0xc8, addr_mode: AddrMode::IMP, operation: Operation::INY, cycles: [2, 0] }, 
     0xc9u8 => Instruction { opcode: 0xc9, addr_mode: AddrMode::IMM, operation: Operation::CMP, cycles: [2, 0] }, 
     0xcau8 => Instruction { opcode: 0xca, addr_mode: AddrMode::IMP, operation: Operation::DEX, cycles: [2, 0] }, 
+    0xcbu8 => Instruction { opcode: 0xcb, addr_mode: AddrMode::IMM, operation: Operation::AXS, cycles: [0, 0] }, 
     0xccu8 => Instruction { opcode: 0xcc, addr_mode: AddrMode::ABS, operation: Operation::CPY, cycles: [4, 0] }, 
     0xcdu8 => Instruction { opcode: 0xcd, addr_mode: AddrMode::ABS, operation: Operation::CMP, cycles: [4, 0] }, 
     0xceu8 => Instruction { opcode: 0xce, addr_mode: AddrMode::ABS, operation: Operation::DEC, cycles: [6, 0] }, 
     0xcfu8 => Instruction { opcode: 0xcf, addr_mode: AddrMode::ABS, operation: Operation::DCP, cycles: [7, 0] }, 
     // 0xd0
     0xd0u8 => Instruction { opcode: 0xd0, addr_mode: AddrMode::REL, operation: Operation::BNE, cycles: [2, 0] }, 
-    0xd3u8 => Instruction { opcode: 0xd3, addr_mode: AddrMode::IZY, operation: Operation::DCP, cycles: [7, 0] }, 
     0xd1u8 => Instruction { opcode: 0xd1, addr_mode: AddrMode::IZY, operation: Operation::CMP, cycles: [5, 0] }, 
+    0xd2u8 => Instruction { opcode: 0xd2, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] }, 
+    0xd3u8 => Instruction { opcode: 0xd3, addr_mode: AddrMode::IZY, operation: Operation::DCP, cycles: [7, 0] }, 
     0xd4u8 => Instruction { opcode: 0xd4, addr_mode: AddrMode::ZPX, operation: Operation::NOP, cycles: [4, 0] },
     0xd5u8 => Instruction { opcode: 0xd5, addr_mode: AddrMode::ZPX, operation: Operation::CMP, cycles: [4, 0] }, 
     0xd6u8 => Instruction { opcode: 0xd6, addr_mode: AddrMode::ZPX, operation: Operation::DEC, cycles: [6, 0] }, 
@@ -287,9 +355,11 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0xe0u8 => Instruction { opcode: 0xe0, addr_mode: AddrMode::IMM, operation: Operation::CPX, cycles: [2, 0] }, 
     0xe1u8 => Instruction { opcode: 0xe1, addr_mode: AddrMode::IZX, operation: Operation::SBC, cycles: [6, 0] }, 
     0xe2u8 => Instruction { opcode: 0xe2, addr_mode: AddrMode::IMM, operation: Operation::NOP, cycles: [2, 0] },
+    0xe3u8 => Instruction { opcode: 0xe3, addr_mode: AddrMode::IZX, operation: Operation::ISB, cycles: [7, 0] }, 
     0xe4u8 => Instruction { opcode: 0xe4, addr_mode: AddrMode::ZP0, operation: Operation::CPX, cycles: [3, 0] }, 
     0xe5u8 => Instruction { opcode: 0xe5, addr_mode: AddrMode::ZP0, operation: Operation::SBC, cycles: [3, 0] }, 
     0xe6u8 => Instruction { opcode: 0xe6, addr_mode: AddrMode::ZP0, operation: Operation::INC, cycles: [5, 0] }, 
+    0xe7u8 => Instruction { opcode: 0xe7, addr_mode: AddrMode::ZP0, operation: Operation::ISB, cycles: [7, 0] }, 
     0xe8u8 => Instruction { opcode: 0xe8, addr_mode: AddrMode::IMP, operation: Operation::INX, cycles: [2, 0] }, 
     0xe9u8 => Instruction { opcode: 0xe9, addr_mode: AddrMode::IMM, operation: Operation::SBC, cycles: [2, 0] }, 
     0xeau8 => Instruction { opcode: 0xea, addr_mode: AddrMode::IMP, operation: Operation::NOP, cycles: [2, 0] }, 
@@ -297,18 +367,24 @@ static INSTRUCTION_SET: Map<u8, Instruction> = phf_map! {
     0xecu8 => Instruction { opcode: 0xec, addr_mode: AddrMode::ABS, operation: Operation::CPX, cycles: [4, 0] }, 
     0xedu8 => Instruction { opcode: 0xed, addr_mode: AddrMode::ABS, operation: Operation::SBC, cycles: [4, 0] }, 
     0xeeu8 => Instruction { opcode: 0xee, addr_mode: AddrMode::ABS, operation: Operation::INC, cycles: [6, 0] }, 
+    0xefu8 => Instruction { opcode: 0xef, addr_mode: AddrMode::ABS, operation: Operation::ISB, cycles: [7, 0] }, 
     // 0xf0
     0xf0u8 => Instruction { opcode: 0xf0, addr_mode: AddrMode::REL, operation: Operation::BEQ, cycles: [2, 0] }, 
     0xf1u8 => Instruction { opcode: 0xf1, addr_mode: AddrMode::IZY, operation: Operation::SBC, cycles: [5, 0] }, 
+    0xf2u8 => Instruction { opcode: 0xf2, addr_mode: AddrMode::IMP, operation: Operation::KIL, cycles: [0, 0] }, 
+    0xf3u8 => Instruction { opcode: 0xf3, addr_mode: AddrMode::IZY, operation: Operation::ISB, cycles: [7, 0] }, 
     0xf4u8 => Instruction { opcode: 0xf4, addr_mode: AddrMode::ZPX, operation: Operation::NOP, cycles: [4, 0] },
     0xf5u8 => Instruction { opcode: 0xf5, addr_mode: AddrMode::ZPX, operation: Operation::SBC, cycles: [4, 0] }, 
     0xf6u8 => Instruction { opcode: 0xf6, addr_mode: AddrMode::ZPX, operation: Operation::INC, cycles: [6, 0] }, 
+    0xf7u8 => Instruction { opcode: 0xf7, addr_mode: AddrMode::ZPX, operation: Operation::ISB, cycles: [7, 0] }, 
     0xf8u8 => Instruction { opcode: 0xf8, addr_mode: AddrMode::IMP, operation: Operation::SED, cycles: [2, 0] }, 
     0xf9u8 => Instruction { opcode: 0xf9, addr_mode: AddrMode::ABY, operation: Operation::SBC, cycles: [4, 0] }, 
     0xfau8 => Instruction { opcode: 0xfa, addr_mode: AddrMode::IMP, operation: Operation::NOP, cycles: [2, 0] },
+    0xfbu8 => Instruction { opcode: 0xfb, addr_mode: AddrMode::ABY, operation: Operation::ISB, cycles: [7, 0] }, 
     0xfcu8 => Instruction { opcode: 0xfc, addr_mode: AddrMode::ABX, operation: Operation::NOP, cycles: [4, 0] },
     0xfdu8 => Instruction { opcode: 0xfd, addr_mode: AddrMode::ABX, operation: Operation::SBC, cycles: [4, 0] }, 
     0xfeu8 => Instruction { opcode: 0xfe, addr_mode: AddrMode::ABX, operation: Operation::INC, cycles: [7, 0] }, 
+    0xffu8 => Instruction { opcode: 0xff, addr_mode: AddrMode::ABX, operation: Operation::ISB, cycles: [7, 0] }, 
 };
 
 pub struct Instruction {
@@ -323,8 +399,9 @@ pub struct Instruction {
 }
 
 impl Instruction {
-    pub fn decode_op(opcode: u8) -> Result<&'static Instruction, Error> {
-        INSTRUCTION_SET.get(&opcode).ok_or(err_msg(format!("Illegal opcode: {:#x}", opcode)))
+    pub fn decode_op(opcode: u8) -> &'static Instruction {
+        INSTRUCTION_SET.get(&opcode)
+            .expect(&format!("Unknown opcode: {:#04x}", opcode))
     }
 }
 
@@ -341,3 +418,31 @@ impl Debug for Instruction {
     } 
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_index_opcode_matches_inst_opcode() {
+        for opcode in 0x00..0xFF {
+            let inst = Instruction::decode_op(opcode);
+            assert_eq!(opcode, inst.opcode,
+                "opcode not matching for {:#04x}", opcode);
+        }
+    }
+
+    #[test]
+    fn test_kill_addr_mode() {
+        for opcode in 0x00..0xFF {
+            let inst = Instruction::decode_op(opcode);
+            if inst.operation == Operation::KIL {
+                assert_eq!(inst.addr_mode, AddrMode::IMP,
+                    "KIL addr mode not IMP for {:#04x}", opcode);
+                assert_eq!(inst.cycles, [0, 0],
+                    "KIL cycles not 0 for {:#04x}", opcode);
+            }
+        }
+    }
+
+       
+}
diff --git a/src/nes/disasm.rs b/src/nes/disasm.rs
index d062bf0..01a830a 100644
--- a/src/nes/disasm.rs
+++ b/src/nes/disasm.rs
@@ -26,8 +26,7 @@ impl Disasm {
             let opcode = mem.readb(addr);
             
             // Decode opcode, default to NOP/IMP to "skip" the byte
-            let i = Instruction::decode_op(opcode)
-                .unwrap_or(Instruction::decode_op(0xeau8).unwrap()); 
+            let i = Instruction::decode_op(opcode); 
             debug!("Disassembling opcode {:#06x}, {:?}", addr, i); 
             
             // debug!("{:?}", i);