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/*
* Copyright (c) 2019, 2020 Inria
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <gtest/gtest-spi.h>
#include <gtest/gtest.h>
#include <utility>
#include "base/gtest/logging.hh"
#include "base/sat_counter.hh"
using namespace gem5;
/**
* Test that an error is triggered when the number of bits exceeds the
* counter's capacity.
*/
TEST(SatCounterDeathTest, BitCountExceeds)
{
#ifdef NDEBUG
GTEST_SKIP() << "Skipping as assertions are "
"stripped out of fast builds";
#endif
gtestLogOutput.str("");
EXPECT_ANY_THROW(SatCounter8 counter(9));
ASSERT_NE(gtestLogOutput.str().find("Number of bits exceeds counter size"),
std::string::npos);
}
/**
* Test that an error is triggered when the initial value is higher than the
* maximum possible value.
*/
TEST(SatCounterDeathTest, InitialValueExceeds)
{
#ifdef NDEBUG
GTEST_SKIP() << "Skipping as assertions are "
"stripped out of fast builds";
#endif
gtestLogOutput.str("");
EXPECT_ANY_THROW(SatCounter8 counter(7, 128));
ASSERT_NE(gtestLogOutput.str().find("initial value exceeds max value"),
std::string::npos);
}
/**
* Test if the maximum value is indeed the maximum value reachable.
*/
TEST(SatCounterTest, MaximumValue)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
SatCounter8 counter(bits);
for (int i = 0; i < 2*max_value; i++) {
counter++;
}
ASSERT_EQ(counter, max_value);
}
/**
* Test if the minimum value is indeed the mimimum value reachable.
*/
TEST(SatCounterTest, MinimumValue)
{
const unsigned bits = 3;
SatCounter8 counter(bits);
for (int i = 0; i < 2; i++) {
counter--;
}
ASSERT_EQ(counter, 0);
}
/**
* Test initializing the counter with a value, updating it and then resetting.
*/
TEST(SatCounterTest, InitialValue)
{
const unsigned bits = 3;
const unsigned initial_value = 4;
SatCounter8 counter(bits, initial_value);
ASSERT_EQ(counter, initial_value);
counter++;
counter.reset();
ASSERT_EQ(counter, initial_value);
}
/**
* Test calculating saturation percentile.
*/
TEST(SatCounterTest, SaturationPercentile)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
SatCounter8 counter(bits);
ASSERT_FALSE(counter.isSaturated());
for (double value = 0.0; value <= max_value; value++, counter++) {
const double saturation = value / max_value;
ASSERT_DOUBLE_EQ(counter.calcSaturation(), saturation);
}
ASSERT_TRUE(counter.isSaturated());
}
/**
* Test abrupt saturation.
*/
TEST(SatCounterTest, Saturate)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
SatCounter8 counter(bits);
counter++;
ASSERT_FALSE(counter.isSaturated());
// Make sure the value added is what was missing to saturate
const unsigned diff = counter.saturate();
ASSERT_EQ(diff, max_value - 1);
ASSERT_TRUE(counter.isSaturated());
}
TEST(SatCounterTest, Saturate16)
{
const unsigned bits = 14;
const unsigned max_value = (1 << bits) - 1;
SatCounter16 counter(bits);
counter++;
ASSERT_FALSE(counter.isSaturated());
// Make sure the value added is what was missing to saturate
const unsigned diff = counter.saturate();
ASSERT_EQ(diff, max_value - 1);
ASSERT_TRUE(counter.isSaturated());
}
/**
* Test back and forth against an int.
*/
TEST(SatCounterTest, IntComparison)
{
const unsigned bits = 3;
SatCounter8 counter(bits);
int value = 0;
ASSERT_EQ(counter++, value++);
ASSERT_EQ(counter++, value++);
ASSERT_EQ(counter--, value--);
ASSERT_EQ(counter++, value++);
ASSERT_EQ(counter++, value++);
ASSERT_EQ(counter--, value--);
ASSERT_EQ(counter++, value++);
ASSERT_EQ(counter--, value--);
ASSERT_EQ(counter--, value--);
ASSERT_EQ(counter++, value++);
ASSERT_EQ(counter--, value--);
ASSERT_EQ(counter--, value--);
ASSERT_EQ(counter, 0);
}
/**
* Test shift operators.
*/
TEST(SatCounterTest, Shift)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
const unsigned initial_value = 1;
SatCounter8 counter(bits, initial_value);
SatCounter8 other(bits, initial_value);
// The saturated shift value is just enough to saturate, since greater
// values could generate undefined behavior
SatCounter8 saturated_counter(bits, bits);
int value = initial_value;
// Test random shifts
counter <<= 2;
value <<= 2;
ASSERT_EQ(counter, value);
counter >>= 1;
value >>= 1;
ASSERT_EQ(counter, value);
// Test saturation
counter <<= bits;
ASSERT_EQ(counter, max_value);
// Test zeroing
counter >>= bits;
ASSERT_EQ(counter, 0);
// Test saturation against other saturating counter
counter.reset();
value = initial_value;
counter <<= other;
value <<= other;
ASSERT_EQ(counter, value);
counter <<= saturated_counter;
value = max_value;
ASSERT_EQ(counter, max_value);
// Test zeroing against other saturating counter
counter >>= other;
value >>= other;
ASSERT_EQ(counter, value);
counter >>= saturated_counter;
ASSERT_EQ(counter, 0);
}
/**
* Make sure the counters cannot be right-shifted by negative numbers, since
* that is undefined behaviour
*/
TEST(SatCounterDeathTest, RightShiftNegative)
{
#ifdef NDEBUG
GTEST_SKIP() << "Skipping as assertions are "
"stripped out of fast builds";
#endif
SatCounter8 counter(8);
ASSERT_DEATH(counter >>= -1, "");
}
/**
* Make sure the counters cannot be left-shifted by negative numbers, since
* that is undefined behaviour
*/
TEST(SatCounterDeathTest, LeftShiftNegative)
{
#ifdef NDEBUG
GTEST_SKIP() << "Skipping as assertions are "
"stripped out of fast builds";
#endif
SatCounter8 counter(8);
ASSERT_DEATH(counter <<= -1, "");
}
/**
* Test both pre and post operators.
*/
TEST(SatCounterTest, PrePostOperators)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
SatCounter8 counter_pre(bits);
SatCounter8 counter_post(bits);
for (int i = 0; i < 2*max_value; i++) {
counter_post++;
SatCounter8 value_pre = ++counter_pre;
ASSERT_EQ(counter_post, value_pre);
}
ASSERT_EQ(counter_pre, max_value);
ASSERT_EQ(counter_post, max_value);
for (int i = 0; i < 2*max_value; i++) {
counter_post--;
SatCounter8 value_pre = --counter_pre;
ASSERT_EQ(counter_post, value_pre);
}
ASSERT_EQ(counter_pre, 0);
ASSERT_EQ(counter_post, 0);
}
/**
* Test copy and move for both constructor and assignment.
*/
TEST(SatCounterTest, CopyMove)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
const unsigned initial_value = 1;
SatCounter8 counter(bits, initial_value);
SatCounter8 deep_copy(1);
SatCounter8 counter_copy(2);
// Increase counter value so that we can check if the inner counter is
// being copied
counter++;
// Copy counter using both the copy constructor and the copy assignment
SatCounter8 counter_copy_constructor(counter);
deep_copy = counter_copy = counter;
ASSERT_EQ(counter_copy_constructor, initial_value + 1);
ASSERT_EQ(counter_copy, initial_value + 1);
ASSERT_EQ(deep_copy, initial_value + 1);
// Make sure max value is the same for all of them, and that modifying
// the copies does not modify the original
for (int i = 0; i < 2*max_value; i++) {
counter_copy_constructor++;
counter_copy++;
deep_copy++;
}
ASSERT_EQ(counter, initial_value + 1);
ASSERT_EQ(counter_copy_constructor, max_value);
ASSERT_EQ(counter_copy, max_value);
ASSERT_EQ(deep_copy, max_value);
// Make sure initial value is the same for all of them
counter_copy_constructor.reset();
counter_copy.reset();
deep_copy.reset();
ASSERT_EQ(counter_copy_constructor, initial_value);
ASSERT_EQ(counter_copy, initial_value);
ASSERT_EQ(deep_copy, initial_value);
// Now check move
SatCounter8 counter_move_constructor(std::move(counter));
ASSERT_EQ(counter, 0);
ASSERT_EQ(counter_move_constructor, initial_value + 1);
SatCounter8 counter_move(bits);
counter_move = std::move(counter_move_constructor);
ASSERT_EQ(counter_move_constructor, 0);
ASSERT_EQ(counter_move, initial_value + 1);
}
/**
* Test add-assignment and subtract assignment.
*/
TEST(SatCounterTest, AddSubAssignment)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
SatCounter8 counter(bits);
SatCounter8 other(bits, 2);
SatCounter8 saturated_counter(bits, max_value);
int value = 0;
// Test add-assignment for a few random values and then saturate
counter += 2;
value += 2;
ASSERT_EQ(counter, value);
counter += 3;
value += 3;
ASSERT_EQ(counter, value);
counter += max_value;
value = max_value;
ASSERT_EQ(counter, value);
// Test subtract-assignment for a few random values until back to zero
counter -= 2;
value -= 2;
ASSERT_EQ(counter, value);
counter -= 3;
value -= 3;
ASSERT_EQ(counter, value);
counter -= max_value;
value = 0;
ASSERT_EQ(counter, value);
// Test add-assignment of other saturating counter
counter += other;
value += other;
ASSERT_EQ(counter, value);
counter += saturated_counter;
value = max_value;
ASSERT_EQ(counter, saturated_counter);
// Test subtract-assignment of other saturating counter
counter -= other;
value -= other;
ASSERT_EQ(counter, value);
counter -= saturated_counter;
ASSERT_EQ(counter, 0);
}
/**
* Test add-assignment and subtract assignment using negative numbers.
*/
TEST(SatCounterTest, NegativeAddSubAssignment)
{
const unsigned bits = 3;
const unsigned max_value = (1 << bits) - 1;
SatCounter8 counter(bits, max_value);
int value = max_value;
// Test add-assignment for a few negative values until zero is reached
counter += -2;
value += -2;
ASSERT_EQ(counter, value);
counter += -3;
value += -3;
ASSERT_EQ(counter, value);
counter += (int)-max_value;
value = 0;
ASSERT_EQ(counter, value);
// Test subtract-assignment for a few negative values until saturation
counter -= -2;
value -= -2;
ASSERT_EQ(counter, value);
counter -= -3;
value -= -3;
ASSERT_EQ(counter, value);
counter -= (int)-max_value;
value = max_value;
ASSERT_EQ(counter, value);
}
/** Test max and min when using SatCounter16. */
TEST(SatCounterTest, Size16)
{
const uint16_t bits_16 = 9;
const uint16_t max_value_16 = (1 << bits_16) - 1;
SatCounter16 counter_16(bits_16);
// Increasing
counter_16++;
ASSERT_EQ(counter_16, 1);
counter_16 <<= 1;
ASSERT_EQ(counter_16, 2);
counter_16 += 2 * max_value_16;
ASSERT_EQ(counter_16, max_value_16);
counter_16++;
ASSERT_EQ(counter_16, max_value_16);
counter_16 <<= 1;
ASSERT_EQ(counter_16, max_value_16);
// Decreasing
counter_16--;
ASSERT_EQ(counter_16, max_value_16 - 1);
counter_16 >>= 1;
ASSERT_EQ(counter_16, (max_value_16 - 1) >> 1);
counter_16 -= 2 * max_value_16;
ASSERT_EQ(counter_16, 0);
counter_16--;
ASSERT_EQ(counter_16, 0);
counter_16 >>= 1;
ASSERT_EQ(counter_16, 0);
}
/** Test max and min when using SatCounter32. */
TEST(SatCounterTest, Size32)
{
const uint32_t bits_32 = 17;
const uint32_t max_value_32 = (1 << bits_32) - 1;
SatCounter32 counter_32(bits_32);
// Increasing
counter_32++;
ASSERT_EQ(counter_32, 1);
counter_32 <<= 1;
ASSERT_EQ(counter_32, 2);
counter_32 += 2 * max_value_32;
ASSERT_EQ(counter_32, max_value_32);
counter_32++;
ASSERT_EQ(counter_32, max_value_32);
counter_32 <<= 1;
ASSERT_EQ(counter_32, max_value_32);
// Decreasing
counter_32--;
ASSERT_EQ(counter_32, max_value_32 - 1);
counter_32 >>= 1;
ASSERT_EQ(counter_32, (max_value_32 - 1) >> 1);
counter_32 -= 2 * max_value_32;
ASSERT_EQ(counter_32, 0);
counter_32--;
ASSERT_EQ(counter_32, 0);
counter_32 >>= 1;
ASSERT_EQ(counter_32, 0);
}
/** Test max and min when using SatCounter64. */
TEST(SatCounterTest, Size64)
{
const uint64_t bits_64 = 33;
const uint64_t max_value_64 = (1ULL << bits_64) - 1;
SatCounter64 counter_64(bits_64);
// Increasing
counter_64++;
ASSERT_EQ(counter_64, 1);
counter_64 <<= 1;
ASSERT_EQ(counter_64, 2);
counter_64 += max_value_64;
ASSERT_EQ(counter_64, max_value_64);
counter_64++;
ASSERT_EQ(counter_64, max_value_64);
counter_64 <<= 1;
ASSERT_EQ(counter_64, max_value_64);
// Decreasing
counter_64--;
ASSERT_EQ(counter_64, max_value_64 - 1);
counter_64 >>= 1;
ASSERT_EQ(counter_64, (max_value_64 - 1) >> 1);
counter_64 -= max_value_64;
ASSERT_EQ(counter_64, 0);
counter_64--;
ASSERT_EQ(counter_64, 0);
counter_64 >>= 1;
ASSERT_EQ(counter_64, 0);
}