cxxrtl: Add simple fuzzing tests for value

tests/cxxrtl/run-test.sh

@@ -10,3 +10,4 @@ run_subtest () {
 }
 
 run_subtest value
+run_subtest value_fuzz

tests/cxxrtl/test_value_fuzz.cc

@@ -0,0 +1,251 @@
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <exception>
+#include <limits>
+#include <random>
+#include <type_traits>
+
+#include "cxxrtl/cxxrtl.h"
+
+template<typename T>
+T rand_int(T min = std::numeric_limits<T>::min(), T max = std::numeric_limits<T>::max())
+{
+	static_assert(std::is_integral<T>::value, "T must be an integral type.");
+	static_assert(!std::is_same<T, signed char>::value && !std::is_same<T, unsigned char>::value,
+			  "Using char with uniform_int_distribution is undefined behavior.");
+
+	static std::mt19937 generator = [] {
+		std::random_device rd;
+		std::mt19937 mt{rd()};
+		return mt;
+	}();
+
+	std::uniform_int_distribution<T> dist(min, max);
+	return dist(generator);
+}
+
+struct BinaryOperationBase
+{
+	void tweak_input(uint64_t &a, uint64_t &b) {}
+};
+
+template<size_t Bits, typename Operation>
+void test_binary_operation_for_bitsize(Operation &op)
+{
+	constexpr int iteration_count = 10000000;
+
+	constexpr uint64_t mask = std::numeric_limits<uint64_t>::max() >> (64 - Bits);
+
+	using chunk_type = typename cxxrtl::value<Bits>::chunk::type;
+	constexpr size_t chunk_bits = cxxrtl::value<Bits>::chunk::bits;
+
+	for (int iteration = 0; iteration < iteration_count; iteration++) {
+		uint64_t ia = rand_int<uint64_t>() >> (64 - Bits);
+		uint64_t ib = rand_int<uint64_t>() >> (64 - Bits);
+		op.tweak_input(ia, ib);
+
+		cxxrtl::value<Bits> va, vb;
+		for (size_t i = 0; i * chunk_bits < Bits; i++) {
+			va.data[i] = (chunk_type)(ia >> (i * chunk_bits));
+			vb.data[i] = (chunk_type)(ib >> (i * chunk_bits));
+		}
+
+		uint64_t iresult = op.reference_impl(Bits, ia, ib) & mask;
+		cxxrtl::value<Bits> vresult = op.template testing_impl<Bits>(va, vb);
+
+		for (size_t i = 0; i * chunk_bits < Bits; i++) {
+			if ((chunk_type)(iresult >> (i * chunk_bits)) != vresult.data[i]) {
+				std::printf("Test failure:\n");
+				std::printf("Bits:    %i\n", Bits);
+				std::printf("a:       %016lx\n", ia);
+				std::printf("b:       %016lx\n", ib);
+				std::printf("iresult: %016lx\n", iresult);
+				std::printf("vresult: %016lx\n", vresult.template get<uint64_t>());
+
+				std::terminate();
+			}
+		}
+	}
+	std::printf("Test passed @ Bits = %i.\n", Bits);
+}
+
+template<typename Operation>
+void test_binary_operation(Operation &op)
+{
+	// Test at a variety of bitwidths
+	test_binary_operation_for_bitsize<8>(op);
+	test_binary_operation_for_bitsize<32>(op);
+	test_binary_operation_for_bitsize<42>(op);
+	test_binary_operation_for_bitsize<63>(op);
+	test_binary_operation_for_bitsize<64>(op);
+}
+
+template<typename Operation>
+struct UnaryOperationWrapper : BinaryOperationBase 
+{
+	Operation &op;
+
+	UnaryOperationWrapper(Operation &op) : op(op) {}
+
+	uint64_t reference_impl(size_t bits, uint64_t a, uint64_t b)
+	{
+		return op.reference_impl(bits, a);
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a, cxxrtl::value<Bits> b)
+	{
+		return op.template testing_impl<Bits>(a);
+	}
+};
+
+template<typename Operation>
+void test_unary_operation(Operation &op)
+{
+	UnaryOperationWrapper<Operation> wrapped(op);
+	test_binary_operation(wrapped);
+}
+
+struct ShlTest : BinaryOperationBase 
+{
+	ShlTest()
+	{
+		std::printf("Randomized tests for value::shl:\n");
+		test_binary_operation(*this);
+	}
+
+	uint64_t reference_impl(size_t bits, uint64_t a, uint64_t b)
+	{
+		return b >= 64 ? 0 : a << b;
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a, cxxrtl::value<Bits> b)
+	{
+		return a.shl(b);
+	}
+
+	void tweak_input(uint64_t &, uint64_t &b)
+	{
+		b &= 0x7f;
+	}
+} shl;
+
+struct ShrTest : BinaryOperationBase 
+{
+	ShrTest()
+	{
+		std::printf("Randomized tests for value::shr:\n");
+		test_binary_operation(*this);
+	}
+
+	uint64_t reference_impl(size_t bits, uint64_t a, uint64_t b)
+	{
+		return b >= 64 ? 0 : a >> b;
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a, cxxrtl::value<Bits> b)
+	{
+		return a.shr(b);
+	}
+
+	void tweak_input(uint64_t &, uint64_t &b)
+	{
+		b &= 0x7f;
+	}
+} shr;
+
+struct SshrTest : BinaryOperationBase 
+{
+	SshrTest()
+	{
+		std::printf("Randomized tests for value::sshr:\n");
+		test_binary_operation(*this);
+	}
+
+	uint64_t reference_impl(size_t bits, uint64_t a, uint64_t b)
+	{
+		int64_t sa = (int64_t)(a << (64 - bits));
+		return sa >> (b >= bits ? 63 : (b + 64 - bits));
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a, cxxrtl::value<Bits> b)
+	{
+		return a.sshr(b);
+	}
+
+	void tweak_input(uint64_t &, uint64_t &b)
+	{
+		b &= 0x7f;
+	}
+} sshr;
+
+struct AddTest : BinaryOperationBase 
+{
+	AddTest()
+	{
+		std::printf("Randomized tests for value::add:\n");
+		test_binary_operation(*this);
+	}
+
+	uint64_t reference_impl(size_t bits, uint64_t a, uint64_t b)
+	{
+		return a + b;
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a, cxxrtl::value<Bits> b)
+	{
+		return a.add(b);
+	}
+} add;
+
+struct SubTest : BinaryOperationBase 
+{
+	SubTest()
+	{
+		std::printf("Randomized tests for value::sub:\n");
+		test_binary_operation(*this);
+	}
+
+	uint64_t reference_impl(size_t bits, uint64_t a, uint64_t b)
+	{
+		return a - b;
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a, cxxrtl::value<Bits> b)
+	{
+		return a.sub(b);
+	}
+} sub;
+
+struct CtlzTest
+{
+	CtlzTest()
+	{
+		std::printf("Randomized tests for value::ctlz:\n");
+		test_unary_operation(*this);
+	}
+
+	uint64_t reference_impl(size_t bits, uint64_t a)
+	{
+		if (a == 0)
+			return bits;
+		return __builtin_clzl(a) - (64 - bits);
+	}
+
+	template<size_t Bits>
+	cxxrtl::value<Bits> testing_impl(cxxrtl::value<Bits> a)
+	{
+		size_t result = a.ctlz();
+		return cxxrtl::value<Bits>((cxxrtl::chunk_t)result);
+	}
+} ctlz;
+
+int main()
+{
+}