# duck-os **Repository Path**: evilbinary/duck-os ## Basic Information - **Project Name**: duck-os - **Description**: 基于scheme写的os - **Primary Language**: Scheme - **License**: MIT - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 2 - **Forks**: 0 - **Created**: 2020-09-10 - **Last Updated**: 2022-05-25 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # duck-os 基于scheme写的os ## 使用 ### 编译 提前安装 bochs ``` ./configure --with-sdl --enable-disasm --enable-all-optimizations --enable-readline --disable-debugger-gui --enable-x86-debugger --enable-a20-pin --enable-fast-function-calls --enable-debugger ``` 编译 ``` mkdir build make ``` ### 运行镜像 ``` make run ``` ## 文档 ### 目录结构 ``` boot.ss 加载loader到内存中，跳转到init init.ss 加载内核到内存中，进入保护模式，跳转到内核 kernel.ss 内核文件 ``` ### BIOS 基本功能 #### 显示相关 INT 10h 1. 设置光标位置 AH=02H BH=页码，DH=列，DL=行 2. 清除屏幕 AH=06H AL=滚动的行（0=清除，被用于CH，CL，DH，DL）， BH=背景颜色和前景颜色，BH=43H，意义为背景颜色为红色，前景颜色为青色。请参考BIOS颜色属性。 CH=高行数，CL=左列数，DH=低行数，DL=右列数 ``` 颜色显示 二进制数 颜色 例子 二进制数 颜色 例子 0000 黑色 black 1000 灰色 gray 0001 蓝色 blue 1001 淡蓝色 light blue 0010 绿色 green 1010 淡绿色 light green 0011 青色 cyan 1000 淡青色 light cyan 0100 红色 red 1100 淡红色 light red 0101 紫红色 magenta 1101 淡紫红色 light magenta 0110 棕色 brown 1110 黄色 yellow 0111 银色 light gray 1111 白色 white ``` #### 磁盘相关 INT 13h 1. 复位 AH 00h DL Drive (bit 7 set means reset both hard and floppy disks) ``` DL = 00h 1st floppy disk ( "drive A:" ) DL = 01h 2nd floppy disk ( "drive B:" ) DL = 02h 3rd floppy disk ( "drive B:" ) . . . DL = 7Fh 128th floppy disk) DL = 80h 1st hard disk DL = 81h 2nd hard disk DL = 82h 3rd hard disk . . . DL = E0h CD/DVD[citation needed], or 97th hard disk . . . DL = FFh 128th hard disk ``` 2. 读取一个扇区 AH=02h: Read Sectors From Drive ``` AH 02h AL Sectors To Read Count CH Cylinder CL Sector DH Head DL Drive ES:BX Buffer Address Pointer Results CF Set On Error, Clear If No Error AH Return Code AL Actual Sectors Read Count ``` ## 保护模式 GDT（Global Descriptor Table，全局描述符表） LDT (Local Descriptor Table，局部描述符表) ``` GDT的每个表项，抽象地可以看成包含四个字段的数据结构：基地址（Base），大小（Limit），标志（Flag），访问信息（Access Byte）。 ``` ``` GDT 1st Double word: Bits Function Description 0-15 Limit 0:15 First 16 bits in the segment limiter 16-31 Base 0:15 First 16 bits in the base address 2nd Double word: Bits Function Description 0-7 Base 16:23 Bits 16-23 in the base address 8-12 Type Segment type and attributes 13-14 Privilege Level 0 = Highest privilege (OS), 3 = Lowest privilege (User applications) 15 Present flag Set to 1 if segment is present 16-19 Limit 16:19 Bits 16-19 in the segment limiter 20-22 Attributes Different attributes, depending on the segment type 23 Granularity Used together with the limiter, to determine the size of the segment 24-31 Base 24:31 The last 24-31 bits in the base address The GDT Descriptor Bits Function Description 0-15 Limit Size of GDT in bytes 16-47 Address GDT's memory address ``` ## 分页 无分页模式 ``` 线性地址等于物理地址 CR0.PG = 0 ``` 32bit模式 ``` CR0.PG = 1 and CR4.PAE = 0 0-11: 页内偏移 12-21: 页表 (Page Table) 22-31: 页表目录表（Page Table Directory ``` PAE模式 ``` CR0.PG = 1, CR4.PAE = 1, and IA32_EFER.LME = 0 0-11：页内偏移 12-20：页表（Page Table） PT PTE 512个 21-29：页表目录表（Page Table Directory） PTD PDE 512个 30-31：页目录指针表（Page Directory Pointer Table） PDPT PDPTE 4个 CR3=>31:30 PDPTE=>29:21 PDE=> 20:12 ``` 内存地址 ``` 0x0500 init 0x4000 page entry 0x7c00 boot 0x8000 kernel ``` ## 任务切换 TSS 任务状态段 ``` x86 Structure offset 0 - 15 16 - 31 0x00 LINK reserved 0x04 ESP0 0x08 SS0 reserved 0x0C ESP1 0x10 SS1 reserved 0x14 ESP2 0x18 SS2 reserved 0x1C CR3 0x20 EIP 0x24 EFLAGS 0x28 EAX 0x2C ECX 0x30 EDX 0x34 EBX 0x38 ESP 0x3C EBP 0x40 ESI 0x44 EDI 0x48 ES reserved 0x4C CS reserved 0x50 SS reserved 0x54 DS reserved 0x58 FS reserved 0x5C GS reserved 0x60 LDTR reserved 0x64 reserved IOPB offset ``` save esp ,eip restore esp ,eip # 参考 https://en.wikipedia.org/wiki/INT_10H https://en.wikipedia.org/wiki/INT_13H https://stanislavs.org/helppc/int_13-1.html https://baike.baidu.com/item/INT10H/22788179?fr=aladdin https://wiki.osdev.org/GDT_Tutorial http://www.osdever.net/tutorials/view/the-world-of-protected-mode https://files.osdev.org/mirrors/geezer/os/pm.htm https://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-vol-3a-part-1-manual.html https://wiki.osdev.org/Task_State_Segment https://wiki.osdev.org/Memory_Map_(x86) http://www.uruk.org/orig-grub/mem64mb.html https://wiki.osdev.org/Detecting_Memory_(x86) https://zh.wikipedia.org/wiki/%E5%85%A8%E5%B1%80%E6%8F%8F%E8%BF%B0%E7%AC%A6%E8%A1%A8