initial upload

src/base/base_bits.c

@@ -0,0 +1,103 @@
+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+#if COMPILER_CL || (COMPILER_CLANG && OS_WINDOWS)
+
+internal U64
+count_bits_set16(U16 val)
+{
+  return __popcnt16(val);
+}
+
+internal U64
+count_bits_set32(U32 val)
+{
+  return __popcnt(val);
+}
+
+internal U64
+count_bits_set64(U64 val)
+{
+  return __popcnt64(val);
+}
+
+internal U64
+ctz32(U32 mask)
+{
+  unsigned long idx;
+  _BitScanForward(&idx, mask);
+  return idx;
+}
+
+internal U64
+ctz64(U64 mask)
+{
+  unsigned long idx;
+  _BitScanForward64(&idx, mask);
+  return idx;
+}
+
+internal U64
+clz32(U32 mask)
+{
+  unsigned long idx;
+  _BitScanReverse(&idx, mask);
+  return 31 - idx;
+}
+
+internal U64
+clz64(U64 mask)
+{
+  unsigned long idx;
+  _BitScanReverse64(&idx, mask);
+  return 63 - idx;
+}
+
+#elif COMPILER_CLANG || COMPILER_GCC
+
+internal U64
+count_bits_set16(U16 val)
+{
+  NotImplemented;
+  return 0;
+}
+
+internal U64
+count_bits_set32(U32 val)
+{
+  NotImplemented;
+  return 0;
+}
+
+internal U64
+count_bits_set64(U64 val)
+{
+  NotImplemented;
+  return 0;
+}
+
+internal U64
+ctz32(U32 val)
+{
+  NotImplemented;
+  return 0;
+}
+
+internal U64
+clz32(U32 val)
+{
+  NotImplemented;
+  return 0;
+}
+
+internal U64
+clz64(U64 val)
+{
+  NotImplemented;
+  return 0;
+}
+
+#else
+# error "bits not defined for this target"
+#endif
+