Day 10

day10/common/cpu.go

@@ -0,0 +1,95 @@
+package common
+
+import (
+  "bufio"
+  "strconv"
+)
+
+
+type CPU struct {
+  registers map[string]int
+}
+
+func NewCPU() *CPU {
+  return &CPU{map[string]int{"X": 1}}
+}
+
+func (cpu CPU) GetRegisterValue(r string) int {
+  return cpu.registers[r]
+}
+
+
+type Instruction interface {
+  ExecuteCycle(*CPU) bool
+}
+
+
+type NoOp struct {
+  currentCycle int
+}
+
+func NewNoOp() *NoOp {
+  return &NoOp{}
+}
+
+func (instruction *NoOp) ExecuteCycle(cpu *CPU) bool {
+  instruction.currentCycle++
+  return instruction.currentCycle == 1
+}
+
+
+type AddX struct {
+  parameter int
+  currentCycle int
+}
+
+func NewAddX(parameter int) *AddX {
+  return &AddX{parameter: parameter, currentCycle: 0}
+}
+
+func (instruction *AddX) ExecuteCycle(cpu *CPU) bool {
+  instruction.currentCycle++
+  if instruction.currentCycle == 2 {
+    cpu.registers["X"] += instruction.parameter
+    return true
+  } else {
+    return false
+  }
+}
+
+
+type Program struct {
+  instructions []Instruction
+  currentInstruction int
+}
+
+func (program *Program) ExecuteCycles(cpu *CPU, nCycles int) bool {
+  for i := 0; i < nCycles && program.currentInstruction < len(program.instructions); i++ {
+    done := program.instructions[program.currentInstruction].ExecuteCycle(cpu)
+    if done {
+      program.currentInstruction++
+    }
+  }
+  return program.currentInstruction == len(program.instructions)
+}
+
+
+func Parse(scanner bufio.Scanner) Program {
+  program := Program{}
+
+  for scanner.Scan() {
+    line := scanner.Text()
+
+    var instruction Instruction
+    switch line[0:4] {
+      case "noop":
+        instruction = NewNoOp()
+      case "addx":
+        value, _ := strconv.Atoi(line[5:])
+        instruction = NewAddX(value)
+    }
+    program.instructions = append(program.instructions, instruction)
+  }
+
+  return program
+}