Clean up Multiboot a bit

Thanks to Aimee for helping out with figuring out the iterator.

src/Multiboot.cc

@@ -53,26 +53,26 @@ Information::setInformation(Information *info)
  */
 
 Information::MemoryMapIterator::MemoryMapIterator(uint32_t address,
-                                                  uint32_t count)
+                                                  uint32_t length)
-    : mCurrent(reinterpret_cast<MemoryChunk *>(address)),
+    : mCurrent(address),
-      mCount(count)
+      mLength(length)
 { }
 
 
 Information::MemoryMapIterator::MemoryMapIterator(const MemoryMapIterator& other)
     : mCurrent(other.mCurrent),
-      mCount(other.mCount)
+      mLength(other.mLength)
 { }
 
 
 Information::MemoryMapIterator&
 Information::MemoryMapIterator::operator++()
 {
-    if (mCount > 0) {
+    if (mLength > 0) {
-        auto p = reinterpret_cast<uint32_t *>(mCurrent);
         // The size of the current struct is stored at (mCurrent - 4) bytes.
-        mCurrent = (mCurrent + p[-1]);
+        auto size = *reinterpret_cast<uint32_t*>(mCurrent) + 4;
-        mCount--;
+        mCurrent = mCurrent + size;
+        mLength = (size > mLength) ? 0 : mLength - size;
     }
     return *this;
 }
@@ -81,7 +81,7 @@ Information::MemoryMapIterator::operator++()
 Information::MemoryMapIterator
 Information::MemoryMapIterator::operator++(int)
 {
-    MemoryMapIterator tmp(reinterpret_cast<uint32_t>(mCurrent), mCount);
+    MemoryMapIterator tmp(mCurrent, mLength);
     operator++();
     return tmp;
 }
@@ -90,10 +90,7 @@ Information::MemoryMapIterator::operator++(int)
 MemoryChunk
 Information::MemoryMapIterator::operator*()
 {
-    if (mCount == 0) {
+    return *reinterpret_cast<MemoryChunk*>(mCurrent+4);
-        return MemoryChunk{0, 0, 0};
-    }
-    return *mCurrent;
 }
 
 
@@ -101,11 +98,11 @@ bool
 Information::MemoryMapIterator::operator==(const MemoryMapIterator& other)
     const
 {
-    if (mCount == 0 && other.mCount == 0) {
+    if (mLength == 0 && other.mLength == 0) {
         // If both iterators have 0 counts, it doesn't matter what the mCurrent members point at.
         return true;
     }
-    return mCurrent == other.mCurrent && mCount == other.mCount;
+    return mCurrent == other.mCurrent && mLength == other.mLength;
 }
 
 
@@ -150,17 +147,6 @@ Information::commandLine()
 }
 
 
-uint32_t
-Information::memoryMapChunks()
-    const
-{
-    if ((mFlags & Present::MemoryMap) == 0) {
-        return 0;
-    }
-    return memoryMapCount;
-}
-
-
 Information::MemoryMapIterator
 Information::memoryMapBegin()
     const
@@ -168,7 +154,8 @@ Information::memoryMapBegin()
     if ((mFlags & Present::MemoryMap) == 0) {
         return memoryMapEnd();
     }
-    return MemoryMapIterator(memoryMapAddress, memoryMapCount);
+    auto& console = kernel::Console::systemConsole();
+    return MemoryMapIterator(mMemoryMapAddress, mMemoryMapLength);
 }
 
 

src/Multiboot.hh

@@ -1,5 +1,5 @@
 /* Multiboot.hh
- * vim: set tw=80:
+ * vim: set tw=120:
  * Eryn Wells <eryn@erynwells.me>
  */
 /**
@@ -44,8 +44,8 @@ struct PACKED Information
         bool operator!=(const MemoryMapIterator& other) const;
 
     private:
-        MemoryChunk *mCurrent;
+        uint32_t mCurrent;
-        uint32_t mCount;
+        uint32_t mLength;
     };
 
     static const Information *information();
@@ -56,7 +56,6 @@ struct PACKED Information
 
     const char* commandLine() const;
 
-    uint32_t memoryMapChunks() const;
     MemoryMapIterator memoryMapBegin() const;
     MemoryMapIterator memoryMapEnd() const;
 
@@ -69,10 +68,7 @@ private:
     /** Amount of upper (1 MB to ...) memory, in KB. Maximally, this value is the address of the first upper memory hole, minus 1 MB. */
     uint32_t mMemUpper;
 
-    /**
+    /** Indicates which BIOS disk the boot loader loaded the OS image from. */
-     * Indicates which BIOS disk the boot loader loaded the OS image from.
-     * Defined only if `bootDevice == true`.
-     */
     struct PACKED {
         /** Third level partition number. If unused this is set to 0xFF. */
         uint8_t partitionLevel3;
@@ -80,33 +76,27 @@ private:
         uint8_t partitionLevel2;
         /** Top-level partition number. */
         uint8_t partitionLevel1;
-        /**
+        /** BIOS drive number, as returned by the `INT 0x13` low-level disk interface. */
-         * BIOS drive number, as returned by the `INT 0x13` low-level disk
-         * interface.
-         */
         uint8_t driveNumber;
-    } bootDevice;
+    } mBootDevice;
 
-    /**
+    /** Pointer to a C-style string containing the command line arguments. */
-     * Pointer to a C-style string containing the command line arguments.
-     * Defined only if `commandLinePresent == true`.
-     */
     uint32_t mCommandLine;
 
     /**
+     * Multiboot Modules
      * Indicates what boot modules were loaded along with the kernel image.
      * Defined only if `modulesPresent == true`.
+     * @{
      */
-    struct PACKED {
+    /** Number of boot modules present. */
-        /** Number of boot modules present. */
+    uint32_t mModulesCount;
-        uint32_t count;
+    /** Pointer to start of boot modules array. */
-        /** Pointer to start of boot modules array. */
+    uint32_t mModulesAddress;
-        uint32_t address;
+    /** @} */
-    } modules;
 
     // TODO: Document these.
-    union PACKED
+    union PACKED {
-    {
         struct PACKED {
             uint32_t tableSize;
             uint32_t stringSize;
@@ -117,42 +107,36 @@ private:
             uint32_t number;
             uint32_t size;
             uint32_t address;
-            uint32_t shndx;
+            uint32_t shndx; // TODO: Bad name. What is this?
         } elf;
     } symbols;
 
     /**
      * @defgroup Memory Map
-     * Points to a buffer containing a memory map of the machine provided by the
+     * Defines a buffer containing a memory map provided by the BIOS.
-     * BIOS. Defined only if `memoryMapPresent == true`.
      * @{
      */
-    /** Number of memory map entries present. */
+    /** Length of the buffer, in bytes. The spec is somewhat unclear on this field. */
-    uint32_t memoryMapCount;
+    uint32_t mMemoryMapLength;
     /** Pointer to start of memory map entry array. */
-    uint32_t memoryMapAddress;
+    uint32_t mMemoryMapAddress;
     /** @} */
 
     /**
-     * Points to a buffer containing a list of drive definitions provided by the
+     * @defgroup Drives
-     * BIOS. Defined only if `drivesPresent == true`.
+     * Defines a buffer containing a list of drive definitions provided by the BIOS.
+     * @{
      */
-    struct PACKED {
+    /** Number of memory map entries present. */
-        /** Number of memory map entries present. */
+    uint32_t mDrivesLength;
-        uint32_t count;
+    /** Pointer to start of memory map entry array. */
-        /** Pointer to start of memory map entry array. */
+    uint32_t mDrivesAddress;
-        uint32_t address;
+    /** @} */
-    } drives;
 
-    /**
+    /** Pointer to a table containing APM information. */
-     * Pointer to the table containing APM information. Defined only if
+    uint32_t mAPMTable;
-     * `apmTablePresent == true`.
-     */
-    uint32_t apmTable;
 
-    /**
+    /** I dunno some VBE stuff. TODO. */
-     * I dunno some VBE stuff. TODO.
-     */
     struct PACKED {
         uint32_t controlInformation;
         uint32_t modeInformation;