Common: Add intrin.h

src/common/bitutils.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2019-2022 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-FileCopyrightText: 2019-2023 Connor McLaughlin <stenzek@gmail.com>
 // SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
 
 #pragma once
@@ -8,6 +8,130 @@
 #include <intrin.h>
 #endif
 
+// Zero-extending helper
+template<typename TReturn, typename TValue>
+ALWAYS_INLINE constexpr TReturn ZeroExtend(TValue value)
+{
+  return static_cast<TReturn>(static_cast<typename std::make_unsigned<TReturn>::type>(
+    static_cast<typename std::make_unsigned<TValue>::type>(value)));
+}
+// Sign-extending helper
+template<typename TReturn, typename TValue>
+ALWAYS_INLINE constexpr TReturn SignExtend(TValue value)
+{
+  return static_cast<TReturn>(
+    static_cast<typename std::make_signed<TReturn>::type>(static_cast<typename std::make_signed<TValue>::type>(value)));
+}
+
+// Type-specific helpers
+template<typename TValue>
+ALWAYS_INLINE constexpr u16 ZeroExtend16(TValue value)
+{
+  return ZeroExtend<u16, TValue>(value);
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u32 ZeroExtend32(TValue value)
+{
+  return ZeroExtend<u32, TValue>(value);
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u64 ZeroExtend64(TValue value)
+{
+  return ZeroExtend<u64, TValue>(value);
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u16 SignExtend16(TValue value)
+{
+  return SignExtend<u16, TValue>(value);
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u32 SignExtend32(TValue value)
+{
+  return SignExtend<u32, TValue>(value);
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u64 SignExtend64(TValue value)
+{
+  return SignExtend<u64, TValue>(value);
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u8 Truncate8(TValue value)
+{
+  return static_cast<u8>(static_cast<typename std::make_unsigned<decltype(value)>::type>(value));
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u16 Truncate16(TValue value)
+{
+  return static_cast<u16>(static_cast<typename std::make_unsigned<decltype(value)>::type>(value));
+}
+template<typename TValue>
+ALWAYS_INLINE constexpr u32 Truncate32(TValue value)
+{
+  return static_cast<u32>(static_cast<typename std::make_unsigned<decltype(value)>::type>(value));
+}
+
+// BCD helpers
+ALWAYS_INLINE constexpr u8 BinaryToBCD(u8 value)
+{
+  return ((value / 10) << 4) + (value % 10);
+}
+ALWAYS_INLINE constexpr u8 PackedBCDToBinary(u8 value)
+{
+  return ((value >> 4) * 10) + (value % 16);
+}
+ALWAYS_INLINE constexpr u8 IsValidBCDDigit(u8 digit)
+{
+  return (digit <= 9);
+}
+ALWAYS_INLINE constexpr u8 IsValidPackedBCD(u8 value)
+{
+  return IsValidBCDDigit(value & 0x0F) && IsValidBCDDigit(value >> 4);
+}
+
+// Boolean to integer
+ALWAYS_INLINE constexpr u8 BoolToUInt8(bool value)
+{
+  return static_cast<u8>(value);
+}
+ALWAYS_INLINE constexpr u16 BoolToUInt16(bool value)
+{
+  return static_cast<u16>(value);
+}
+ALWAYS_INLINE constexpr u32 BoolToUInt32(bool value)
+{
+  return static_cast<u32>(value);
+}
+ALWAYS_INLINE constexpr u64 BoolToUInt64(bool value)
+{
+  return static_cast<u64>(value);
+}
+
+// Integer to boolean
+template<typename TValue>
+ALWAYS_INLINE constexpr bool ConvertToBool(TValue value)
+{
+  return static_cast<bool>(value);
+}
+
+// Unsafe integer to boolean
+template<typename TValue>
+ALWAYS_INLINE bool ConvertToBoolUnchecked(TValue value)
+{
+  // static_assert(sizeof(uint8) == sizeof(bool));
+  bool ret;
+  std::memcpy(&ret, &value, sizeof(bool));
+  return ret;
+}
+
+// Generic sign extension
+template<int NBITS, typename T>
+ALWAYS_INLINE constexpr T SignExtendN(T value)
+{
+  // http://graphics.stanford.edu/~seander/bithacks.html#VariableSignExtend
+  constexpr int shift = 8 * sizeof(T) - NBITS;
+  return static_cast<T>((static_cast<std::make_signed_t<T>>(value) << shift) >> shift);
+}
+
 /// Returns the number of zero bits before the first set bit, going MSB->LSB.
 template<typename T>
 ALWAYS_INLINE unsigned CountLeadingZeros(T value)