Merge pull request #81 from nekernel-org/dev

feat! breaking changes on kernel sources.

1 files changed, 228 insertions, 0 deletions

diff --git a/src/boot/BootKit/Shared/bit.h b/src/boot/BootKit/Shared/bit.h
new file mode 100644
index 00000000..1ac29c89
--- /dev/null
+++ b/src/boot/BootKit/Shared/bit.h
@@ -0,0 +1,228 @@
+#ifndef UTL_BIT_H
+#define UTL_BIT_H
+
+#include <bit>
+
+namespace utl {
+
+/**
+ * @brief Size of object in terms of bits.
+ *
+ * @tparam T Object type
+ * @return Number of bits
+ */
+template <class T>
+constexpr auto bit_size() {
+  return sizeof(T) * 8;
+}
+
+/**
+ * @brief Integer with all bits set to 1.
+ *
+ * @tparam T Integer type
+ * @return All set integer
+ */
+template <class T>
+constexpr T bit_full() {
+  return T(-1);
+}
+
+/**
+ * @brief Wrap around mask for power of two number of bits
+ * within given integer type. For example:
+ * [ bit_wrap<uint8_t>  = 8  - 1 = 0b111   ]
+ * [ bit_wrap<uint16_t> = 16 - 1 = 0b1111  ]
+ * [ bit_wrap<uint32_t> = 32 - 1 = 0b11111 ]
+ *
+ * @tparam T Integer type
+ * @return Wrap around mask for number of bits
+ */
+template <class T>
+constexpr T bit_wrap() {
+  return bit_size<T>() - 1;
+}
+
+/**
+ * @brief Number of bits to fit bit_wrap<T> result, in other words
+ * bit width of (sizeof(T) * 8 - 1). For example:
+ * [ bit_shft<uint8_t>  = bit_width(0b111)      = 3 ]
+ * [ bit_shft<uint16_t> = bit_width(0b1111)     = 4 ]
+ * [ bit_shft<uint32_t> = bit_width(0b11111)    = 5 ]
+ *
+ * @tparam T Integer type
+ * @return Number of bits to shift to divide by sizeof(T) * 8
+ */
+template <class T>
+constexpr auto bit_shft() {
+  return std::bit_width(bit_wrap<T>());
+}
+
+/**
+ * @brief Round up division by number of bits within given integer type,
+ * which sizeof(T) * 8 is power of two.
+ *
+ * @tparam T Inetegr type
+ * @param x Dividend
+ * @return Quotient
+ */
+template <class T>
+constexpr auto bit_ceil(auto x) {
+  return (x + bit_wrap<T>()) >> bit_shft<T>();
+}
+
+/**
+ * @brief Count leading zeros.
+ *
+ * @param x Unsigned integer argument
+ * @return Number of leading zeros
+ */
+constexpr unsigned cntlz(auto x) {
+  if constexpr (std::is_same_v<decltype(x), int>)
+    return std::countl_zero(unsigned(x));
+  else
+    return std::countl_zero(x);
+}
+
+/**
+ * @brief Count trailing zeros.
+ *
+ * @param x Unsigned integer argument
+ * @return Number of trailing zeros
+ */
+constexpr unsigned cnttz(auto x) {
+  if constexpr (std::is_same_v<decltype(x), int>)
+    return std::countr_zero(unsigned(x));
+  else
+    return std::countr_zero(x);
+}
+
+/**
+ * @brief Get number of words (integers) required to store N bits.
+ *
+ * @tparam T Word integer type
+ * @param n Number of bits to store
+ * @return Number of words
+ */
+template <class T>
+constexpr size_t words_in_bits(size_t n) {
+  return (n >> bit_shft<T>()) + !!(n & bit_wrap<T>());
+}
+
+/**
+ * @brief Get number of bytes required to store N bits.
+ *
+ * @param n Number of bits to store
+ * @return Number of bytes
+ */
+constexpr size_t bytes_in_bits(size_t n) {
+  return words_in_bits<uint8_t>(n);
+}
+
+/**
+ * @brief Make integer with bit at given position.
+ *
+ * @tparam T Inetegr type
+ * @param n Bit position
+ * @return Integer with set bit
+ */
+template <class T = unsigned>
+constexpr T bit(int n) {
+  return T(1) << n;
+}
+
+/**
+ * @brief Get n-th bit of an integer.
+ *
+ * @tparam T Integer type
+ * @param x Integer
+ * @param n Bit position from LSB
+ * @return true if set
+ */
+template <class T>
+constexpr bool get_bit(T x, int n) {
+  return (x >> n) & 1;
+}
+
+/**
+ * @brief Set n-th bit of an integer.
+ *
+ * @tparam T Integer type
+ * @param x Integer
+ * @param n Bit position from LSB
+ */
+template <class T>
+constexpr void set_bit(T& x, int n) {
+  x |= 1 << n;
+}
+
+/**
+ * @brief Clear n-th bit of an integer.
+ *
+ * @tparam T Integer type
+ * @param x Integer
+ * @param n Bit position from LSB
+ */
+template <class T>
+constexpr void clr_bit(T& x, int n) {
+  x &= ~(1 << n);
+}
+
+/**
+ * @brief Get n-th bit in array of words (starting from LSB).
+ *
+ * @tparam T Word type
+ * @param p Array of words
+ * @param n Index of bit to get
+ * @return true if set
+ */
+template <class T>
+constexpr bool get_arr_bit(const T* p, unsigned n) {
+  return get_bit(p[n >> bit_shft<T>()], n & bit_wrap<T>());
+}
+
+/**
+ * @brief Set n-th bit in array of words (starting from LSB).
+ *
+ * @tparam T Word type
+ * @param p Array of words
+ * @param n Index of bit to set
+ */
+template <class T>
+constexpr void set_arr_bit(T* p, unsigned n) {
+  set_bit(p[n >> bit_shft<T>()], n & bit_wrap<T>());
+}
+
+/**
+ * @brief Clear n-th bit in array of words (starting from LSB).
+ *
+ * @tparam T Word type
+ * @param p Array of words
+ * @param n Index of bit to clear
+ */
+template <class T>
+constexpr void clr_arr_bit(T* p, unsigned n) {
+  clr_bit(p[n >> bit_shft<T>()], n & bit_wrap<T>());
+}
+
+/**
+ * @brief Shift bits left in array of integer elements from least significant bit
+ * and considering 0-th byte as the right most.
+ * uint16_t example: 0b10000000'11100001 ==> 0b00000001'11000010.
+ *
+ * @tparam T Integer type
+ * @tparam L Length of array
+ * @param x Array of integers, nullptr not acceptable!
+ * @param len Number of elements
+ */
+template <class T, size_t L>
+constexpr void shift_left(T (&x)[L]) {
+  for (int i = L - 1; i > 0; --i) {
+    x[i] <<= 1;
+    x[i] |= x[i - 1] >> bit_wrap<T>();
+  }
+  x[0] <<= 1;
+}
+
+}  // namespace utl
+
+#endif
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