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• Since only one WyrmLog can be directed at the video at once, you may want to make WyrmLog explictly a singleton class.
• In the methods you posted earlier, you return *this for method declared &WyrmLog. You should only be declaring them as this; the extra indirection isn't needed, as this is already a pointer. Your compiler ought to have thrown a warning, or even an error, on that; add the -Wall switch to you build command string to make sure it does in the future.
• Remember that the video text buffer is made up of character-attribute pairs. I would make a simple packed struct type made up of a char and a uint8_t to represent the video elements:

  Code: Select all

  struct __attribute__ ((__packed__))  DisplayChar
  {
      char text;
      uint8_t attribute;
  }

  You'll need to #include <cstdint> for the uint8_t type, which means having a version of it in your library. This is adviseable anyway, as the size-specified types are more precise when it comes to system work.
• You have the video base as a static const int variable. You should be using a pointer rather than an int for this. If you use the struct above, change that to static const *DisplayChar TEXT_BUFFER_PAGE_0 = 0xB8000;.
• You should make your video handling (not just for logging) flexible enough to handle different text modes. As such, the max width and max height should not be constants.
• You have the base of the video buffer, but you don't have anything representing it's current state. You need a pointer to the current char-attribute pair for the cursor, and some sort of indicator for the text mode. A method from moving the cursor along the lines of goto_xy() would be adviseable as well.

Schol-R-LEA wrote:In the methods you posted earlier, you return *this for method declared &WyrmLog. You should only be declaring them as this; the extra indirection isn't needed, as this is already a pointer. Your compiler ought to have thrown a warning, or even an error, on that; add the -Wall switch to you build command string to make sure it does in the future.

Since only one WyrmLog can be directed at the video at once..., you may want to make WyrmLog explictly a singleton class.

In the methods you posted earlier, you return *this for method declared &WyrmLog.

Remember that the video text buffer is made up of character-attribute pairs.

VideoCell * video;

You'll need to #include <cstdint> for the uint8_t type, which means having a version of it in your library.

You have the video base as a static const int variable.

You should make your video handling (not just for logging) flexible enough to handle different text modes. As such, the max width and max height should not be constants.

If you are declaring the object as class WyrmLog rather than Log, and using a local variable rather than a pointer to memory on the heap, then it shouldn't matter if it is a virtual function or not; it will always use the WyrmLog version of the function directly, without a vtable lookup. Whatever the cause of the problem is, it isn't because it is a pure virtual function.

As for
Code:
WyrmLog log();

text = 0x100000
rodata = 0x10232E
data = 0x1028E6
bss = 0x103670

text = 0x100000
rodata = 0x103000
data = 0x104000
bss = 0x105000

• Why does this work? Do sections have to be page aligned because of the memory protection model or is there any other reason I still don’t know of?
• Have I really fixed the error, or is it working just by chance and it might reappear in the future when the kernel grows?
• Why did my vtables ended up in the data section?