Initial implementation of register machine emulator.

.gitignore

@@ -0,0 +1,6 @@
+Session.vim
+Emulator
+build/*
+.undodir
+.ccls
+.tup/*

Tupfile

@@ -0,0 +1,12 @@
+CXX      = g++
+CXXFLAGS = -pedantic -std=c++17 -Wall -Wno-unused-parameter -Wno-reorder -Wno-sign-compare -Wno-address -Wno-noexcept-type -Wno-unknown-attributes -Wno-unknown-warning-option
+CPPFLAGS =
+LDFLAGS  =
+LIBS     = -lgmpxx -lgmp
+
+SRC_DIR   = src
+BUILD_DIR = build
+PROG      = Emulator
+
+: foreach $(SRC_DIR)/*.cpp |> $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c %f -o %o |> $(BUILD_DIR)/%B.o
+: $(BUILD_DIR)/*.o |> $(CXX) %f $(LDFLAGS) $(LIBS) -o %o |> $(PROG)

src/.clang-format

@@ -0,0 +1,25 @@
+---
+BasedOnStyle: llvm
+IndentWidth: 4
+---
+AccessModifierOffset: -4
+AllowShortFunctionsOnASingleLine: Empty
+AlwaysBreakTemplateDeclarations: Yes
+BreakBeforeBraces: Attach
+BreakConstructorInitializers: BeforeColon
+Cpp11BracedListStyle: false
+ColumnLimit: 100
+DerivePointerAlignment: false
+FixNamespaceComments: true
+IndentCaseLabels: true
+IndentPPDirectives: AfterHash
+Language: Cpp
+NamespaceIndentation: All
+PointerAlignment: Left
+SortIncludes: true
+SortUsingDeclarations: true
+Standard: Cpp11
+TabWidth: 4
+UseTab: ForIndentation
+
+...

src/main.cpp

@@ -0,0 +1,81 @@
+#include "register.hpp"
+#include <iomanip>
+#include <iostream>
+#include <map>
+
+Register& getOrDefault(std::map<RegIndex, Register>& mapping, const RegIndex& lookup);
+
+int main() {
+	const constexpr size_t registerIndexPadding = 6;
+	bool executing = true;
+
+	std::cout << "Please enter the program" << std::endl;
+
+	RegIndex pc = 0;
+	Register reg;
+	std::map<RegIndex, Register> registers{};
+
+	std::cin >> reg;
+	auto registerStates = toList(reg);
+
+	std::cout << "\nRegister states at startup:\n";
+	RegIndex i = 0;
+
+	for (; i < registerStates.size(); i++) {
+		const auto registerState = registerStates[i];
+
+		registers.insert(std::make_pair(i, registerState));
+		std::cout << std::setw(registerIndexPadding) << i << ": " << registerState << "\n";
+	}
+
+	std::cout << std::setw(registerIndexPadding) << i << ": 0...\n\n";
+	std::cout << "Beginning Execution..." << std::endl;
+
+	registers.insert(std::make_pair(pc, reg));
+
+	while (executing) {
+		std::cout << "L" << pc << "\t";
+		Register instruction = getOrDefault(registers, pc);
+
+		if (instruction == 0) { /* HALT instruction. */
+			std::cout << "HALT" << std::endl;
+			executing = false;
+			continue;
+		}
+
+		auto splitInstruction = toPair<false>(instruction);
+
+		if (splitInstruction.first % 2 == 0) { /* R+ instruction */
+			RegIndex sourceRegisterIndex = splitInstruction.first.get_ui();
+			RegIndex destinationLabel = splitInstruction.second.get_ui();
+
+			std::cout << "R" << sourceRegisterIndex << u8"\u207a \u21a3 " << destinationLabel
+			          << "\n";
+
+			getOrDefault(registers, sourceRegisterIndex)++;
+			pc = destinationLabel;
+		} else {
+			RegIndex sourceRegisterIndex = splitInstruction.first.get_ui();
+
+			auto branches = toPair<true>(splitInstruction.second);
+			RegIndex trueLabel = branches.first.get_ui();
+			RegIndex falseLabel = branches.second.get_ui();
+
+			std::cout << "R" << sourceRegisterIndex << "\u207b \u21a3 " << trueLabel << ", "
+			          << falseLabel << "\n";
+
+			auto& sourceRegister = getOrDefault(registers, sourceRegisterIndex);
+
+			if (sourceRegister > 0) {
+				sourceRegister--;
+				pc = trueLabel;
+			} else
+				pc = falseLabel;
+		}
+	}
+}
+
+Register& getOrDefault(std::map<RegIndex, Register>& mapping, const RegIndex& lookup) {
+	auto valueIter = mapping.try_emplace(lookup, Register{ 0 });
+	return valueIter.first->second;
+}

src/register.cpp

@@ -0,0 +1,43 @@
+#include "register.hpp"
+
+template <>
+std::pair<Register, Register> toPair<false>(Register unsplit) {
+	Register x = 0;
+
+	/* Skip to the first 1 bit in representation */
+	while (unsplit % 2 != 1) {
+		unsplit >>= 1;
+		x++;
+	}
+
+	unsplit >>= 1;
+
+	return std::make_pair(x, unsplit);
+}
+
+template <>
+std::pair<Register, Register> toPair<true>(Register unsplit) {
+	Register x = 0;
+
+	/* Skip past the first 1 bits in representation */
+	while (unsplit % 2 == 1) {
+		unsplit >>= 1;
+		x++;
+	}
+
+	unsplit >>= 1;
+
+	return std::make_pair(x, unsplit);
+}
+
+std::vector<Register> toList(Register unsplit) {
+	std::vector<Register> list{};
+
+	while (unsplit != 0) {
+		const auto splitPair = toPair<false>(unsplit);
+		unsplit = splitPair.second;
+		list.push_back(splitPair.first);
+	}
+
+	return list;
+}

src/register.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <cstdint>
+#include <gmpxx.h>
+#include <utility>
+
+using Register = mpz_class;
+using RegIndex = uint16_t;
+
+template <bool mapZero>
+std::pair<Register, Register> toPair(Register unsplit);
+
+std::vector<Register> toList(Register unsplit);