1 files changed, 44 insertions, 13 deletions

diff --git a/src/vmm.h b/src/vmm.h
index 9de487b..252e5bb 100644
--- a/src/vmm.h
+++ b/src/vmm.h
@@ -1,31 +1,62 @@
-#include <stdlib.h>
-
 #pragma once
+#include <result.h>
+#include <stdlib.h>
 
 extern "C" void dump_address();
 
-struct page_table {
-  uint32_t* addr;
-};
-
 class vmm {
 public:
+  enum Error { NoError, TableNotAllocated, AddressAlreadyMapped };
+
+  struct address {
+    size_t offset : 12 = 0;
+    size_t page_idx : 10 = 0;
+    size_t table_idx : 10 = 0;
+
+    constexpr address(uint32_t addr)
+        : offset{static_cast<size_t>(addr & 0x3ff)},
+          page_idx{static_cast<size_t>((addr >> 12) & 0x3ff)},
+          table_idx{static_cast<size_t>(addr >> 22)} {}
+
+    constexpr address(size_t table, size_t page) : page_idx{page}, table_idx{table} {}
+
+    constexpr operator uint32_t() const {
+      return static_cast<uint32_t>(table_idx << 22) | static_cast<uint32_t>(page_idx << 12) |
+             static_cast<uint32_t>(offset);
+    }
+  } __attribute__((packed));
+
   vmm(uint32_t* addr = nullptr);
 
-  constexpr static size_t table_id(uint32_t offset) {
+  [[deprecated]] constexpr static size_t table_id(uint32_t offset) {
     offset &= 0xfff00000;
     offset /= (4 * 1024 * 1024);
     return static_cast<size_t>(offset);
   }
-  constexpr static size_t page_id(uint32_t offset) { return static_cast<size_t>(offset / 4096); }
+  [[deprecated]] constexpr static size_t page_id(uint32_t offset) { return static_cast<size_t>(offset / 4096); }
 
-  uint32_t map(uint32_t phys_addr, uint32_t offset);
+  static void reload() {
+    uint32_t cr0;
+    asm volatile("mov %%cr0, %0" : "=r"(cr0));
+    asm volatile("mov %0, %%cr0" : : "r"(cr0));
+  }
+
+  [[nodiscard]] Result<uint32_t, Error> map(uint32_t phys_addr, const address dest);
 
 private:
+  class page_table {
+  public:
+    page_table(uint32_t);
+    bool set(size_t idx, uint32_t a) {
+      if (pages[idx] != 0) return false;
+      pages[idx] = a | 0x003;
+      return true;
+    }
+
+  private:
+    uint32_t* pages;
+  };
+
   uint32_t* directory;
 };
 
-static_assert(vmm::table_id(0x00001234) == 0);
-static_assert(vmm::table_id(0x00400000) == 1);
-static_assert(vmm::table_id(0xc0000000) == 768);
-static_assert(vmm::table_id(0xc03ff000) == 768);