Handout

kernel/memory/page.h

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+#pragma once
+#include "../types.h"
+
+namespace Page {
+/*! \brief Page Bits
+ * We use the least significant 12 Bits
+ */
+const uintptr_t BITS = 12;
+
+/*! \brief Page size
+ * We go with 2^12 = 4K
+ */
+const uintptr_t SIZE = 1 << BITS;
+
+/*! \brief Mask for Page
+ */
+const uintptr_t MASK = SIZE - 1;
+
+/*! \brief Round to next (upper) page aligned address
+ *  \param address memory address
+ *  \return nearest ceiling page aligned address
+ */
+template <typename T>
+T ceil(T address) {
+	return (address + MASK) & (~MASK);
+}
+
+/*! \brief Round to last (lower) page aligned address
+ *  \param address memory address
+ *  \return nearest floor page aligned address
+ */
+template <typename T>
+T floor(T ptr) {
+	return ptr & (~MASK);
+}
+
+/*! \brief Get offset in page
+ *  \param address memory address
+ *  \return offset
+ */
+template <typename T>
+T offset(T ptr) {
+	return ptr & MASK;
+}
+
+/*! \brief Check if address is page aligned
+ *  \param address memory address
+ *  \return true if page aligned address
+ */
+template <typename T>
+bool aligned(T ptr) {
+	return offset(ptr) == 0;
+}
+
+}  // namespace Page