mirror of
https://github.com/RetroDECK/Duckstation.git
synced 2024-11-23 22:25:42 +00:00
69 lines
2.2 KiB
C++
69 lines
2.2 KiB
C++
|
#include "common/bitutils.h"
|
||
|
|
#include "gtest/gtest.h"
|
||
|
|
#include <type_traits>
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
static inline constexpr unsigned ManualCountLeadingZeros(T value)
|
||
|
|
{
|
||
|
|
constexpr unsigned BITS = sizeof(T) * 8u;
|
||
|
|
constexpr T MASK = T(1) << (BITS - 1);
|
||
|
|
|
||
|
|
unsigned count = 0;
|
||
|
|
for (unsigned i = 0; i < BITS && (value & MASK) == 0; i++)
|
||
|
|
{
|
||
|
|
count++;
|
||
|
|
value <<= 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return count;
|
||
|
|
}
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
static inline constexpr unsigned ManualCountTrailingZeros(T value)
|
||
|
|
{
|
||
|
|
constexpr unsigned BITS = sizeof(T) * 8u;
|
||
|
|
constexpr auto MASK = static_cast<std::make_unsigned_t<T>>(1);
|
||
|
|
|
||
|
|
auto u_value = static_cast<std::make_unsigned_t<T>>(value);
|
||
|
|
|
||
|
|
unsigned count = 0;
|
||
|
|
for (unsigned i = 0; i < BITS && (u_value & MASK) != MASK; i++)
|
||
|
|
{
|
||
|
|
count++;
|
||
|
|
u_value >>= 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return count;
|
||
|
|
}
|
||
|
|
|
||
|
|
TEST(BitUtils, Test8Bit)
|
||
|
|
{
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(1)), ManualCountLeadingZeros(u8(1)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(2)), ManualCountLeadingZeros(u8(2)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(4)), ManualCountLeadingZeros(u8(4)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(8)), ManualCountLeadingZeros(u8(8)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(16)), ManualCountLeadingZeros(u8(16)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(32)), ManualCountLeadingZeros(u8(32)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(64)), ManualCountLeadingZeros(u8(64)));
|
||
|
|
ASSERT_EQ(CountLeadingZeros(u8(128)), ManualCountLeadingZeros(u8(128)));
|
||
|
|
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(1)), ManualCountTrailingZeros(u8(1)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(2)), ManualCountTrailingZeros(u8(2)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(4)), ManualCountTrailingZeros(u8(4)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(8)), ManualCountTrailingZeros(u8(8)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(16)), ManualCountTrailingZeros(u8(16)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(32)), ManualCountTrailingZeros(u8(32)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(64)), ManualCountTrailingZeros(u8(64)));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(u8(128)), ManualCountTrailingZeros(u8(128)));
|
||
|
|
}
|
||
|
|
|
||
|
|
TEST(BitUtils, Test16Bit)
|
||
|
|
{
|
||
|
|
for (u32 i = 1; i < 0x10000; i++)
|
||
|
|
{
|
||
|
|
u16 value = Truncate16(i);
|
||
|
|
ASSERT_EQ(CountLeadingZeros(value), ManualCountLeadingZeros(value));
|
||
|
|
ASSERT_EQ(CountTrailingZeros(value), ManualCountTrailingZeros(value));
|
||
|
|
}
|
||
|
|
}
|