diff --git a/2018/day19/Cargo.lock b/2018/day19/Cargo.lock
new file mode 100644
index 0000000..d8c290d
--- /dev/null
+++ b/2018/day19/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "day19"
+version = "0.1.0"
+
diff --git a/2018/day19/Cargo.toml b/2018/day19/Cargo.toml
new file mode 100644
index 0000000..4cd6ec4
--- /dev/null
+++ b/2018/day19/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "day19"
+version = "0.1.0"
+authors = ["Andrew Coleman <penguincoder@gmail.com>"]
+edition = "2018"
+
+[dependencies]
diff --git a/2018/day19/input b/2018/day19/input
new file mode 100644
index 0000000..a3ba0ea
--- /dev/null
+++ b/2018/day19/input
@@ -0,0 +1,37 @@
+#ip 3
+addi 3 16 3
+seti 1 8 4
+seti 1 4 5
+mulr 4 5 1
+eqrr 1 2 1
+addr 1 3 3
+addi 3 1 3
+addr 4 0 0
+addi 5 1 5
+gtrr 5 2 1
+addr 3 1 3
+seti 2 1 3
+addi 4 1 4
+gtrr 4 2 1
+addr 1 3 3
+seti 1 3 3
+mulr 3 3 3
+addi 2 2 2
+mulr 2 2 2
+mulr 3 2 2
+muli 2 11 2
+addi 1 3 1
+mulr 1 3 1
+addi 1 17 1
+addr 2 1 2
+addr 3 0 3
+seti 0 3 3
+setr 3 0 1
+mulr 1 3 1
+addr 3 1 1
+mulr 3 1 1
+muli 1 14 1
+mulr 1 3 1
+addr 2 1 2
+seti 0 8 0
+seti 0 9 3
diff --git a/2018/day19/src/main.rs b/2018/day19/src/main.rs
new file mode 100644
index 0000000..2bac3ba
--- /dev/null
+++ b/2018/day19/src/main.rs
@@ -0,0 +1,245 @@
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+
+type Registers = [usize; 6];
+
+#[derive(Debug)]
+struct Opcode {
+    cmd: String,
+    args: OpcodeArgs,
+}
+
+type OpcodeArgs = [usize; 3];
+
+struct Program {
+    registers: Registers,
+    instructions: Vec<Opcode>,
+    ip: usize,
+}
+
+fn iter_to_opcode(iter: &mut std::str::SplitWhitespace) -> Opcode {
+    Opcode {
+        cmd: iter.nth(0).unwrap().to_string(),
+        args: [
+            iter.nth(0).unwrap().parse::<usize>().unwrap(),
+            iter.nth(0).unwrap().parse::<usize>().unwrap(),
+            iter.nth(0).unwrap().parse::<usize>().unwrap(),
+        ],
+    }
+}
+
+fn read_program_from_file(filename: &str) -> Program {
+    let mut lines = BufReader::new(File::open(filename).unwrap()).lines();
+    let ip = lines.nth(0).unwrap();
+    let instructions = lines
+        .map(|line| iter_to_opcode(&mut line.unwrap().split_whitespace()))
+        .collect();
+    Program {
+        registers: [0usize; 6],
+        instructions,
+        ip: ip
+            .unwrap()
+            .split_whitespace()
+            .nth(1)
+            .unwrap()
+            .parse::<usize>()
+            .unwrap(),
+    }
+}
+
+fn addr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] + input_registers[args[1]];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn addi(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] + args[1];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn mulr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] * input_registers[args[1]];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn muli(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] * args[1];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn banr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] & input_registers[args[1]];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn bani(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] & args[1];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn borr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] | input_registers[args[1]];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn bori(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]] | args[1];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn setr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = input_registers[args[0]];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn seti(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    output_registers[args[2]] = args[0];
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn gtir(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    if args[0] > input_registers[args[1]] {
+        output_registers[args[2]] = 1;
+    } else {
+        output_registers[args[2]] = 0;
+    }
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn gtri(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    if input_registers[args[0]] > args[1] {
+        output_registers[args[2]] = 1;
+    } else {
+        output_registers[args[2]] = 0;
+    }
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn gtrr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    if input_registers[args[0]] > input_registers[args[1]] {
+        output_registers[args[2]] = 1;
+    } else {
+        output_registers[args[2]] = 0;
+    }
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn eqir(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    if args[0] == input_registers[args[1]] {
+        output_registers[args[2]] = 1;
+    } else {
+        output_registers[args[2]] = 0;
+    }
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn eqri(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    if input_registers[args[0]] == args[1] {
+        output_registers[args[2]] = 1;
+    } else {
+        output_registers[args[2]] = 0;
+    }
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn eqrr(input_registers: Registers, args: OpcodeArgs) -> Registers {
+    let mut output_registers = input_registers.clone();
+    if input_registers[args[0]] == input_registers[args[1]] {
+        output_registers[args[2]] = 1;
+    } else {
+        output_registers[args[2]] = 0;
+    }
+    //dbg!(output_registers);
+    output_registers
+}
+
+fn execute_program(program: &mut Program) {
+    while let Some(op) = program.instructions.get(program.registers[program.ip]) {
+        //dbg!(op);
+        let output_registers = match op.cmd.as_str() {
+            "addr" => addr(program.registers, op.args),
+            "addi" => addi(program.registers, op.args),
+            "mulr" => mulr(program.registers, op.args),
+            "muli" => muli(program.registers, op.args),
+            "banr" => banr(program.registers, op.args),
+            "bani" => bani(program.registers, op.args),
+            "borr" => borr(program.registers, op.args),
+            "bori" => bori(program.registers, op.args),
+            "setr" => setr(program.registers, op.args),
+            "seti" => seti(program.registers, op.args),
+            "gtir" => gtir(program.registers, op.args),
+            "gtri" => gtri(program.registers, op.args),
+            "gtrr" => gtrr(program.registers, op.args),
+            "eqir" => eqir(program.registers, op.args),
+            "eqri" => eqri(program.registers, op.args),
+            "eqrr" => eqrr(program.registers, op.args),
+            _ => panic!("No decoded instruction available for {}", op.cmd),
+        };
+        program.registers[0] = output_registers[0];
+        program.registers[1] = output_registers[1];
+        program.registers[2] = output_registers[2];
+        program.registers[3] = output_registers[3];
+        program.registers[4] = output_registers[4];
+        program.registers[5] = output_registers[5];
+        program.registers[program.ip] += 1;
+    }
+    program.registers[program.ip] -= 1;
+}
+
+fn main() {
+    let mut program = read_program_from_file("input");
+    execute_program(&mut program);
+    println!("final value of register 0: {:?}", program.registers[0]);
+    let mut program2 = read_program_from_file("input");
+    program2.registers[0] = 1;
+    execute_program(&mut program2);
+    println!("final value of register 0 with modified start value {}", program2.registers[0]);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sample_one() {
+        let mut program = read_program_from_file("test-input");
+        execute_program(&mut program);
+        let output_registers = program.registers;
+        assert_eq!(output_registers[0], 6);
+        assert_eq!(output_registers[1], 5);
+        assert_eq!(output_registers[2], 6);
+        assert_eq!(output_registers[3], 0);
+        assert_eq!(output_registers[4], 0);
+        assert_eq!(output_registers[5], 9);
+    }
+}
diff --git a/2018/day19/test-input b/2018/day19/test-input
new file mode 100644
index 0000000..d7d2a21
--- /dev/null
+++ b/2018/day19/test-input
@@ -0,0 +1,8 @@
+#ip 0
+seti 5 0 1
+seti 6 0 2
+addi 0 1 0
+addr 1 2 3
+setr 1 0 0
+seti 8 0 4
+seti 9 0 5