1 files changed, 179 insertions, 0 deletions
diff --git a/tests/unit_tests/mul_div.cpp b/tests/unit_tests/mul_div.cpp
new file mode 100644
index 000000000..291e4f191
--- /dev/null
+++ b/tests/unit_tests/mul_div.cpp
@@ -0,0 +1,179 @@
+// Copyright (c) 2012-2013 The Cryptonote developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "gtest/gtest.h"
+
+#include "common/int-util.h"
+
+namespace
+{
+  TEST(mul128, handles_zero)
+  {
+    uint64_t hi, lo;
+
+    lo = mul128(0, 0, &hi);
+    ASSERT_EQ(lo, 0);
+    ASSERT_EQ(hi, 0);
+
+    lo = mul128(7, 0, &hi);
+    ASSERT_EQ(lo, 0);
+    ASSERT_EQ(hi, 0);
+
+    lo = mul128(0, 7, &hi);
+    ASSERT_EQ(lo, 0);
+    ASSERT_EQ(hi, 0);
+  }
+
+  TEST(mul128, handles_one)
+  {
+    uint64_t hi, lo;
+
+    lo = mul128(1, 1, &hi);
+    ASSERT_EQ(lo, 1);
+    ASSERT_EQ(hi, 0);
+
+    lo = mul128(7, 1, &hi);
+    ASSERT_EQ(lo, 7);
+    ASSERT_EQ(hi, 0);
+
+    lo = mul128(1, 7, &hi);
+    ASSERT_EQ(lo, 7);
+    ASSERT_EQ(hi, 0);
+  }
+
+  TEST(mul128_without_carry, multiplies_correctly)
+  {
+    uint64_t hi, lo;
+
+    lo = mul128(0x3333333333333333, 5, &hi);
+    ASSERT_EQ(lo, 0xffffffffffffffff);
+    ASSERT_EQ(hi, 0);
+
+    lo = mul128(5, 0x3333333333333333, &hi);
+    ASSERT_EQ(lo, 0xffffffffffffffff);
+    ASSERT_EQ(hi, 0);
+
+    lo = mul128(0x1111111111111111, 0x1111111111111111, &hi);
+    ASSERT_EQ(lo, 0x0fedcba987654321);
+    ASSERT_EQ(hi, 0x0123456789abcdf0);;
+  }
+
+  TEST(mul128_with_carry_1_only, multiplies_correctly)
+  {
+    uint64_t hi, lo;
+
+    lo = mul128(0xe0000000e0000000, 0xe0000000e0000000, &hi);
+    ASSERT_EQ(lo, 0xc400000000000000);
+    ASSERT_EQ(hi, 0xc400000188000000);
+  }
+
+  TEST(mul128_with_carry_2_only, multiplies_correctly)
+  {
+    uint64_t hi, lo;
+
+    lo = mul128(0x10000000ffffffff, 0x10000000ffffffff, &hi);
+    ASSERT_EQ(lo, 0xdffffffe00000001);
+    ASSERT_EQ(hi, 0x0100000020000000);
+  }
+
+  TEST(mul128_with_carry_1_and_2, multiplies_correctly)
+  {
+    uint64_t hi, lo;
+
+    lo = mul128(0xf1f2f3f4f5f6f7f8, 0xf9f0fafbfcfdfeff, &hi);
+    ASSERT_EQ(lo, 0x52118e5f3b211008);
+    ASSERT_EQ(hi, 0xec39104363716e59);
+
+    lo = mul128(0xffffffffffffffff, 0xffffffffffffffff, &hi);
+    ASSERT_EQ(lo, 0x0000000000000001);
+    ASSERT_EQ(hi, 0xfffffffffffffffe);
+  }
+
+  TEST(div128_32, handles_zero)
+  {
+    uint32_t reminder;
+    uint64_t hi;
+    uint64_t lo;
+
+    reminder = div128_32(0, 0, 7, &hi, &lo);
+    ASSERT_EQ(reminder, 0);
+    ASSERT_EQ(hi, 0);
+    ASSERT_EQ(lo, 0);
+
+    // Division by zero is UB, so can be tested correctly
+  }
+
+  TEST(div128_32, handles_one)
+  {
+    uint32_t reminder;
+    uint64_t hi;
+    uint64_t lo;
+
+    reminder = div128_32(0, 7, 1, &hi, &lo);
+    ASSERT_EQ(reminder, 0);
+    ASSERT_EQ(hi, 0);
+    ASSERT_EQ(lo, 7);
+
+    reminder = div128_32(7, 0, 1, &hi, &lo);
+    ASSERT_EQ(reminder, 0);
+    ASSERT_EQ(hi, 7);
+    ASSERT_EQ(lo, 0);
+  }
+
+  TEST(div128_32, handles_if_dividend_less_divider)
+  {
+    uint32_t reminder;
+    uint64_t hi;
+    uint64_t lo;
+
+    reminder = div128_32(0, 1383746, 1645825, &hi, &lo);
+    ASSERT_EQ(reminder, 1383746);
+    ASSERT_EQ(hi, 0);
+    ASSERT_EQ(lo, 0);
+  }
+
+  TEST(div128_32, handles_if_dividend_dwords_less_divider)
+  {
+    uint32_t reminder;
+    uint64_t hi;
+    uint64_t lo;
+
+    reminder = div128_32(0x5AD629E441074F28, 0x0DBCAB2B231081F1, 0xFE735CD6, &hi, &lo);
+    ASSERT_EQ(reminder, 0xB9C924E9);
+    ASSERT_EQ(hi, 0x000000005B63C274);
+    ASSERT_EQ(lo, 0x9084FC024383E48C);
+  }
+
+  TEST(div128_32, works_correctly)
+  {
+    uint32_t reminder;
+    uint64_t hi;
+    uint64_t lo;
+
+    reminder = div128_32(2, 0, 2, &hi, &lo);
+    ASSERT_EQ(reminder, 0);
+    ASSERT_EQ(hi, 1);
+    ASSERT_EQ(lo, 0);
+
+    reminder = div128_32(0xffffffffffffffff, 0, 0xffffffff, &hi, &lo);
+    ASSERT_EQ(reminder, 0);
+    ASSERT_EQ(hi, 0x0000000100000001);
+    ASSERT_EQ(lo, 0);
+
+    reminder = div128_32(0xffffffffffffffff, 5846, 0xffffffff, &hi, &lo);
+    ASSERT_EQ(reminder, 5846);
+    ASSERT_EQ(hi, 0x0000000100000001);
+    ASSERT_EQ(lo, 0);
+
+    reminder = div128_32(0xffffffffffffffff - 1, 0, 0xffffffff, &hi, &lo);
+    ASSERT_EQ(reminder, 0xfffffffe);
+    ASSERT_EQ(hi, 0x0000000100000000);
+    ASSERT_EQ(lo, 0xfffffffefffffffe);
+
+    reminder = div128_32(0x2649372534875028, 0xaedbfedc5adbc739, 0x27826534, &hi, &lo);
+    ASSERT_EQ(reminder, 0x1a6dc2e5);
+    ASSERT_EQ(hi, 0x00000000f812c1f8);
+    ASSERT_EQ(lo, 0xddf2fdb09bc2e2e9);
+  }
+}