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Memory Map

Memory map

Adress start	Adress end	Description
0x0	0xFFF	EfiBootServicesCode
0x1000	0x5FFFF	EfiConventionalMemory
0x60000	0x6FFFF	Boot Info
0x70000	0x9FFFF	EfiConventionalMemory
0xA0000	0xFFFFF	Used by VGA
0x100000	0x100FFF	kernel header code
0x101000	0x101FFF	page directory entry
0x102000	0x102FFF	page table entry
0x103000	0x103FFF	page table entry
0x104000	0x104FFF	page table entry
Get more paging information via: https://wiki.osdev.org/Paging

x86_64 CPU address map strategy

64 bits address on paper, but only 48 bits are available.

1GB page

Page Directory Index	Page Table Index	Page Intern Offset	Total Bits
9 bits (512 items)	9 bits (512 items)	30 bits (1 GB Page)	48 bits

2MB page

Page Directory 1 Index	Page Directory 2 Index	Page Table Index	Page Intern Offset	Total Bits
9 bits (512 items)	9 bits (512 items)	9 bits (512 items)	21 bits (2 MB Page)	48 bits

4KB page

Page Directory 1 Index	Page Directory 2 Index	Page Directory 3 Index	Page Table Index	Page Intern Offset	Total Bits
9 bits (512 items)	9 bits (512 items)	9 bits (512 items)	9 bits (512 items)	12 bits (4 KB Page)	48 bits

TODO

• bootloader
• kernel
  • std
    • type
  • system
    • boot
      • BootInfo
    • io
      • screen
      • text_mode_screen
      • pic
      • keyborad
    • memory
      • memory
      • allocPage
      • freePage
    • media
      • color
      • font

Update Log

2021/2/19: I'm back, modify folder structure.

2020/11/14: move gdt to kernel/system/memory/gdt/gdt.hpp.

2020/10/24: We can see what we type on screen, awesome! However, this keyboard driver does not support some key now.

2020/10/18: Update Screen and TextModeScreen, add buffer for TextModeScreen.

2020/10/15: Update IRQs.

2020/10/14: Cleaned up my codes. Split system::io::pic to system::io::port and system::interrupt::pic.

2020/10/13: Partially finished pic. Now we can answer keyboard message. Renamed some symbols. Deleted IDT_Table from head.asm, instead idtTable is defined at system::io::pic. Added std type, like uint8_t, uint16_t, etc.

2020/10/9: What an awesome change! I replaced cmake with msbuild, and separated the project to many cpp source files. Thus, we can complie object files respectively. Then I re-organized file structure, it's more clear now.

2020/10/5: Memory management almost done. Now it's quite simply, but let's do some other parts, and then go back to the memory management.

2020/10/4: Didn't update for a long time. I was so busy recently. Partially updated memory management and used sfinae to implement print now.

2020/8/30: Update memory map.

2020/8/26: Implement BootInfo, now we can access data which comes from UEFI, and I use system::boot::bootInfo->graphicInfo to replace hard-coded screen parameters(memory, width, height, etc.)

2020/8/24: I need a class to put bootloader's information(e.g. graphic memory address, memory map, etc.). So, I add an namepsace boot under system.

2020/8/23: In order to support singleten pattern for class Screen, I need to support memory management first. Thus, I can call Screen::initScreen(), and use Screen::getInstance() to get the only Screen object. Those above is beneficial for the consistency of screen data.