init repo

lab4/csrc/mm.h

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+// Copyright 2022 hrpccs
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+typedef unsigned int uint32;
+typedef uint32 pte_t;
+typedef uint32* pagetable_t;
+
+#define PGSIZE 4096 // bytes per page
+#define PGSHIFT 12  // bits of offset within a page
+
+#define PGROUNDUP(sz)  (((sz)+PGSIZE-1) & ~(PGSIZE-1))
+#define PGROUNDDOWN(a) (((a)) & ~(PGSIZE-1))
+
+#define PTE_V (1L << 0) // valid
+#define PTE_R (1L << 1)
+#define PTE_W (1L << 2)
+#define PTE_X (1L << 3)
+#define PTE_U (1L << 4) // 1 -> user can access
+
+// shift a physical address to the right place for a PTE.
+#define PA2PTE(pa) ((((uint32)pa) >> 12) << 10)
+
+#define PTE2PA(pte) (((pte) >> 10) << 12)
+
+#define PTE_FLAGS(pte) ((pte) & 0x3FF)
+
+// extract the two 10-bit page table indices from a virtual address.
+#define PXMASK          0x3FF // 10 bits
+#define PXSHIFT(level)  (PGSHIFT+(10*(level)))
+#define PX(level, va) ((((uint32) (va)) >> PXSHIFT(level)) & PXMASK)
+
+#define MAXVA (1L << (10 + 10 + 12))