Added bsr() function to util

tests/CMakeLists.txt

@@ -74,7 +74,7 @@ set(SOURCES
 	src/keccak_tests.cpp
 	src/main.cpp
 	src/pool_block_tests.cpp
-	src/varint_tests.cpp
+	src/util_tests.cpp
 	src/wallet_tests.cpp
 	../external/src/cryptonote/crypto-ops-data.c
 	../external/src/cryptonote/crypto-ops.c
@@ -160,6 +160,19 @@ endif()
 
 add_definitions(/DZMQ_STATIC /DP2POOL_LOG_DISABLE)
 
+include(CheckCXXSourceCompiles)
+
+check_cxx_source_compiles("int main(){ return __builtin_clzll(1);}" HAVE_BUILTIN_CLZLL)
+check_cxx_source_compiles("#include <intrin.h>\n#pragma intrinsic(_BitScanReverse64)\nint main(){unsigned long r;_BitScanReverse64(&r,1);return r;}" HAVE_BITSCANREVERSE64)
+
+if (HAVE_BUILTIN_CLZLL)
+	add_definitions(/DHAVE_BUILTIN_CLZLL)
+endif()
+
+if (HAVE_BITSCANREVERSE64)
+	add_definitions(/DHAVE_BITSCANREVERSE64)
+endif()
+
 add_executable(${CMAKE_PROJECT_NAME} ${HEADERS} ${SOURCES})
 target_link_libraries(${CMAKE_PROJECT_NAME} debug ${ZMQ_LIBRARY_DEBUG} debug ${UV_LIBRARY_DEBUG} optimized ${ZMQ_LIBRARY} optimized ${UV_LIBRARY} ${LIBS})
 add_custom_command(TARGET ${CMAKE_PROJECT_NAME} POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different "${CMAKE_SOURCE_DIR}/src/crypto_tests.txt" $<TARGET_FILE_DIR:${CMAKE_PROJECT_NAME}>)

tests/src/util_tests.cpp

@@ -21,7 +21,7 @@
 
 namespace p2pool {
 
-TEST(varint, read_write)
+TEST(util, varint)
 {
 	std::vector<uint8_t> v;
 	v.reserve(16);
@@ -82,4 +82,12 @@ TEST(varint, read_write)
 	ASSERT_EQ(readVarint(buf2, buf2 + 1, check), nullptr);
 }
 
+TEST(util, bsr)
+{
+	for (uint64_t i = 0, x = 1; i <= 63; ++i, x <<= 1) {
+		ASSERT_EQ(bsr(x), i);
+		ASSERT_EQ(bsr_reference(x), i);
+	}
+}
+
 }