;============================================================================================================================== BaseOfStack equ 0x07c00 ; Boot状态下堆栈基地址 STACK_ADDR equ 0x7bea ; 堆栈栈顶 BaseOfBoot equ 1000h ; added by mingxuan 2020-9-12 OffsetOfBoot equ 7c00h ; load Boot sector to BaseOfBoot:OffsetOfBoot OffsetOfActiPartStartSec equ 7e00h ; 活动分区的起始扇区号相对于BaseOfBoot的偏移量 ;added by mingxuan 2020-9-12 ; 该变量来自分区表，保存在该内存地址，用于在os_boot和loader中查找FAT32文件 BOOT_FAT32_INFO equ 0x5A ;位于boot中的FAT32配置信息的长度 ;added by mingxuan 2020-9-16 DATA_BUF_OFF equ 0x2000 ; 目录 被加载的缓冲区地址 OSLOADER_SEG equ 0x09000 ; 起始段地址 OSLOADER_SEG_OFF equ 0x0100 ;FAT_START_SECTOR equ 0x820 ; FAT表的起始扇区号 DWORD ;FAT_START_SECTOR equ 0x1020 ; FAT表的起始扇区号 DWORD ; for test 2020-9-10, mingxuan ;DATA_START_SECTOR equ 0xd6a ; 数据区起始扇区号 DWORD ;DATA_START_SECTOR equ 0x156a ; 数据区起始扇区号 DWORD ; for test 2020-9-10, mingxuan ;DATA_START_SECTOR equ 0x13a4 ; 数据区起始扇区号 DWORD ; for test 2020-9-13, mingxuan DIR_PER_SECTOR equ 0x10 ; 每个扇区所容纳的目录 BYTE ; 扩展磁盘服务所使用的地址包 DAP_SECTOR_HIGH equ 4 ; 起始扇区号的高32位 ( 每次调用需要重置 ) DWORD DAP_SECTOR_LOW equ 8 ; 起始扇区号的低32位 ( 每次调用需要重置 ) DWORD DAP_BUFFER_SEG equ 10 ; 缓冲区段地址 ( 每次调用需要重置 ) WORD DAP_BUFFER_OFF equ 12 ; 缓冲区偏移 ( 每次调用需要重置 ) WORD DAP_RESERVED2 equ 13 ; 保留字节 DAP_READ_SECTORS equ 14 ; 要处理的扇区数(1 - 127 ) DAP_RESERVED1 equ 15 ; 保留字节 DAP_PACKET_SIZE equ 16 ; 包的大小为16字节 CURRENT_CLUSTER equ 20 ; 当前正在处理的簇号 DWORD ; 目录项结构 OFF_START_CLUSTER_HIGH equ 20 ; 起始簇号高位 WORD OFF_START_CLUSTER_LOW equ 26 ; 起始簇号低位 WORD ; 相关常量 DIR_NAME_FREE equ 0x00 ; 该项是空闲的 DIR_ENTRY_SIZE equ 32 ; 每个目录项的尺寸 ; 簇属性 CLUSTER_MASK equ 0FFFFFFFH ; 簇号掩码 CLUSTER_LAST equ 0FFFFFF8H ;0xFFFFFFF8-0xFFFFFFFF表示文件的最后一个簇 ; added by mingxuan 2020-9-12 BPB_BytesPerSec equ (OffsetOfBoot + 0xb) ;每扇区字节数 BPB_SecPerClu equ (OffsetOfBoot + 0xd) ;每簇扇区数 BPB_RsvdSecCnt equ (OffsetOfBoot + 0xe) ;保留扇区数 BPB_NumFATs equ (OffsetOfBoot + 0x10) ;FAT表数 BPB_RootEntCnt equ (OffsetOfBoot + 0x11) ;FAT32不使用 BPB_TotSec16 equ (OffsetOfBoot + 0x13) ;扇区总数 BPB_Media equ (OffsetOfBoot + 0x15) ;介质描述符 BPB_FATSz16 equ (OffsetOfBoot + 0x16) ;每个FAT表的大小扇区数(FAT32不使用) BPB_SecPerTrk equ (OffsetOfBoot + 0x18) ;每磁道扇区数 BPB_NumHeads equ (OffsetOfBoot + 0x1a) ;磁头数 BPB_HiddSec equ (OffsetOfBoot + 0x1c) ;分区已使用扇区数 BPB_TotSec32 equ (OffsetOfBoot + 0x20) ;文件系统大小扇区数 BS_SecPerFAT equ (OffsetOfBoot + 0x24) ;每个FAT表大小扇区数 BS_Flag equ (OffsetOfBoot + 0x28) ;标记 BS_Version equ (OffsetOfBoot + 0x2a) ;版本号 BS_RootClus equ (OffsetOfBoot + 0x2c) ;根目录簇号 BS_FsInfoSec equ (OffsetOfBoot + 0x30) ;FSINFO扇区号 BS_BackBootSec equ (OffsetOfBoot + 0x32) ;备份引导扇区位置 BS_Unuse1 equ (OffsetOfBoot + 0x34) ;未使用 ;BS_Unuse2 equ (OffsetOfBoot + 0x40) ;未使用 ;deleted by mingxuan 2020-9-15 ;BS_Unuse3 equ (OffsetOfBoot + 0x41) ;未使用 ;deleted by mingxuan 2020-9-15 BS_DriveNum equ (OffsetOfBoot + 0x40) ;设备号 BS_Unuse4 equ (OffsetOfBoot + 0x41) ;未使用 BS_ExtBootFlag equ (OffsetOfBoot + 0x42) ;扩展引导标志 BS_VolNum equ (OffsetOfBoot + 0x43) ;卷序列号 BS_VolName equ (OffsetOfBoot + 0x47) ;卷标 ;============================================================================================================================== ;org 07c00h ;deleted by mingxuan 2020-9-16 org (07c00h + BOOT_FAT32_INFO) ;FAT322规范规定第90~512个字节(共423个字节)是引导程序 ;modified by mingxuan 2020-9-16 ;jmp START ;deleted by mingxuan 2020-9-15 ;nop ;deleted by mingxuan 2020-9-15 FAT_START_SECTOR DD 0 ;FAT表的起始扇区号 ;added by mingxuan 2020-9-17 DATA_START_SECTOR DD 0 ;数据区起始扇区号 ;added by mingxuan 2020-9-17 ;deleted by mingxuan 2020-9-12 ;BS_OEM DB 'mkfs.fat' ;文件系统标志 ;BPB_BytesPerSec DW 0x200 ;每扇区字节数 ;BPB_SecPerClu DB 1 ;每簇扇区数 ;BPB_RsvdSecCnt DW 0x20 ;保留扇区数 ;BPB_NumFATs DB 2 ;FAT表数 ;BPB_RootEntCnt DW 0 ;FAT32不使用 ;BPB_TotSec16 DW 0 ;扇区总数 ;BPB_Media DB 0xf8 ;介质描述符 ;BPB_FATSz16 DW 0 ;每个FAT表的大小扇区数 ;BPB_SecPerTrk DW 0x3f ;每磁道扇区数 ;BPB_NumHeads DW 0xff ;磁头数 ;BPB_HiddSec DD 0 ;分区已使用扇区数 ;BPB_TotSec32 DD 0x015791 ;文件系统大小扇区数 ;BS_SecPerFAT DD 0x02a5 ;每个FAT表大小扇区数 ;BS_Flag DW 0 ;标记 ;BS_Version DW 0 ;版本号 ;BS_RootClus DD 2 ;根目录簇号 ;BS_FsInfoSec DW 1 ;FSINFO扇区号 ;BS_BackBootSec DW 6 ;备份引导扇区位置 ;BS_Unuse1 DD 0 ;未使用 ;BS_Unuse2 DD 0 ;未使用 ;BS_Unuse3 DD 0 ;未使用 ;BS_DriveNum DB 0x80 ;设备号 ;BS_Unuse4 DB 0x01 ;未使用 ;BS_ExtBootFlag DB 0x29 ;扩展引导标志 ;BS_VolNum DD 0xbe3a8ff5 ;卷序列号 ;BS_VolName DB 'MZY hd boot' ;卷标 START: cld mov ax, cs mov ds, ax mov es, ax ;deleted by mingxuan 2020-9-13 mov ss, ax ; 清屏 ; for test, added by mingxuan 2020-9-15 ; pusha ; mov dx, 0184fh ; 右下角: (80, 50) ; int 10h ; int 10h ; popa ;added by mingxuan 2020-9-13 ;mov ax, BaseOfBoot ;mov fs, ax ;es存储BaseOfBoot，用于查找FAT32的配置信息 ;FAT_START_SECTOR DD ([fs:OffsetOfActiPartStartSec] + [fs:BPB_RsvdSecCnt]) ; 计算FAT表的起始扇区号 ; added by mingxuan 2020-9-17 mov eax, [ OffsetOfActiPartStartSec] add ax, [ BPB_RsvdSecCnt ] mov [FAT_START_SECTOR], eax ; 计算数据区起始扇区号 ; added by mingxuan 2020-9-17 add eax, [BS_SecPerFAT] add eax, [BS_SecPerFAT] mov [DATA_START_SECTOR], eax mov sp, STACK_ADDR mov bp, BaseOfStack mov dword [bp - DAP_SECTOR_HIGH ], 00h ;mov byte [bp - DAP_RESERVED1 ], 00h ;deleted by mingxuan 2020-9-17 ;mov byte [bp - DAP_RESERVED2 ], 00h ;deleted by mingxuan 2020-9-17 mov byte [bp - DAP_PACKET_SIZE ], 10h mov byte [bp - DAP_READ_SECTORS], 01h mov word [bp - DAP_BUFFER_SEG ], 01000h ;for test, added by mingxuan 2020-9-4 ;call DispStr ; ;jmp $ jmp _SEARCH_LOADER _MISSING_LOADER: ; 显示没有装载程序 ;for test, added by mingxuan 2020-9-10 ;call DispStr ; ;JMP $ ;for test, added by mingxuan 2020-9-10 ; 清屏 ; for test, added by mingxuan 2020-9-15 ;pusha ;mov dx, 0184fh ; 右下角: (80, 50) ;int 10h ; int 10h ;popa _DISK_ERROR: ; 显示磁盘错误信息 ;for test, added by mingxuan 2020-9-4 ; 清屏 ; for test, added by mingxuan 2020-9-15 ;pusha ;mov dx, 0184fh ; 右下角: (80, 50) ;int 10h ; int 10h ;popa JMP $ ReadSector: pusha mov ah, 42h ;ah是功能号，扩展读对应0x42 lea si, [BP - DAP_PACKET_SIZE] ;使用扩展int13时DAP结构体首地址传给si ;mov dl, [BS_DriveNum] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov dl, [fs:BS_DriveNum] ;modified by mingxuan 2020-9-13 mov dl, [BS_DriveNum] ;modified by mingxuan 2020-9-17 ;mov dl, 0x80 ;jmp $ int 13h jc _DISK_ERROR ;jmp $ ; 清屏 ; for test, added by mingxuan 2020-9-15 ;pusha ;mov dx, 0184fh ; 右下角: (80, 50) ;int 10h ; int 10h ;popa popa ret _SEARCH_LOADER: mov word [bp - DAP_BUFFER_OFF], DATA_BUF_OFF ;mov eax, dword [BS_RootClus] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov eax, dword [fs:BS_RootClus] ;modified by mingxuan 2020-9-13 ;mov eax, dword [BS_RootClus] ;modified by mingxuan 2020-9-17 mov eax, [BS_RootClus] mov dword [bp - CURRENT_CLUSTER], eax ;for test, added by mingxuan 2020-9-4 ;call DispStr ; ;jmp $ _NEXT_ROOT_CLUSTER: ; 根据簇号计算扇区号, mingxuan 2020-9-13 dec eax dec eax xor ebx, ebx ;mov bl, byte [BPB_SecPerClu] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov bl, byte [fs:BPB_SecPerClu] ;modified by mingxuan 2020-9-13 mov bl, [BPB_SecPerClu] ;modified by mingxuan 2020-9-17 ;jmp $ mul ebx ;add eax, DATA_START_SECTOR ;deleted by mingxuan 2020-9-17 add eax, [DATA_START_SECTOR] ;modified by mingxuan 2020-9-17 mov dword [BP - DAP_SECTOR_LOW], eax ;mov dl, [BPB_SecPerClu] ;deleted by mingxuan 2020-9-13 ;mov dl, byte [es:BPB_SecPerClu] ;modified by mingxuan 2020-9-13 ;mov dl, [fs:BPB_SecPerClu] ;modified by mingxuan 2020-9-15 mov dl, [BPB_SecPerClu] ;modified by mingxuan 2020-9-17 ;jmp $ _NEXT_ROOT_SECTOR: call ReadSector ;for test, added by mingxuan 2020-9-4 ;call DispStr ; ;jmp $ mov di, DATA_BUF_OFF mov bl, DIR_PER_SECTOR _NEXT_ROOT_ENTRY: cmp byte [di], DIR_NAME_FREE jz _MISSING_LOADER push di; mov si, LoaderName ;add si, BOOT_FAT32_INFO ; added by mingxuan 2020-9-16 ;mov si, 0x7df1 ; for test, added by mingxuan 2020-9-16 mov cx, 10 repe cmpsb jcxz _FOUND_LOADER pop di add di, DIR_ENTRY_SIZE dec bl jnz _NEXT_ROOT_ENTRY dec dl jz _CHECK_NEXT_ROOT_CLUSTER inc dword [bp - DAP_SECTOR_LOW] jmp _NEXT_ROOT_SECTOR ; Comments, added by mingxuan 2020-9-10 ;==================================================================== ; 检查是否还有下一个簇(读取FAT表的相关信息) ; N = 数据簇号 ; FAT_BYTES(在FAT表中的偏移) = N*4 (FAT32) ; FAT_SECTOR = FAT_BYTES / BPB_BytesPerSec ; FAT_OFFSET = FAT_BYTES % BPB_BytesPerSec ;==================================================================== _CHECK_NEXT_ROOT_CLUSTER: ; 检查是否还有下一个簇 ; 计算FAT表项所在的簇号和偏移 ; FatOffset(在FAT表中的偏移) = ClusterNum(簇号) * 4 XOR EDX, EDX MOV EAX, DWORD[BP - CURRENT_CLUSTER] SHL EAX, 2 ;FatOffset = ClusterNum * 4 XOR ECX, ECX ;MOV CX, WORD [ BPB_BytesPerSec ] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov cx, word [fs:BPB_BytesPerSec] ;modified by mingxuan 2020-9-13 mov cx, word [BPB_BytesPerSec] ;modified by mingxuan 2020-9-17 DIV ECX ; EAX = Sector EDX = OFFSET ; 计算FAT表的起始扇区号 ; added by mingxuan 2020-9-17 ;mov ebx, dword [ fs:OffsetOfActiPartStartSec ] ;add bx, word [ fs:BPB_RsvdSecCnt ] ; 设置缓冲区地址 ;ADD EAX, FAT_START_SECTOR ;deleted by mingxuan 2020-9-17 ADD EAX, [FAT_START_SECTOR] ;modified by mingxuan 2020-9-17 ;add eax, ebx ;modified by mingxuan 2020-9-17 MOV DWORD [ BP - DAP_SECTOR_LOW ], EAX call ReadSector ; 检查下一个簇 MOV DI,DX ADD DI,DATA_BUF_OFF MOV EAX, DWORD[DI] ; EAX = 下一个要读的簇号 AND EAX, CLUSTER_MASK MOV DWORD[ BP - CURRENT_CLUSTER ],EAX CMP EAX,CLUSTER_LAST ; CX >= 0FFFFFF8H，则意味着没有更多的簇了 JB _NEXT_ROOT_CLUSTER ;for test, added by mingxuan 2020-9-10 ;call DispStr ; JMP _MISSING_LOADER _FOUND_LOADER: ;for test, added by mingxuan 2020-9-10 ;call DispStr ; ;JMP $ ;for test, added by mingxuan 2020-9-10 ; 目录结构地址放在DI中 pop di xor eax, eax mov ax, [di + OFF_START_CLUSTER_HIGH] ; 起始簇号高32位 shl ax, 16 mov ax, [di + OFF_START_CLUSTER_LOW] ; 起始簇号低32位 mov dword [ bp - CURRENT_CLUSTER ], eax mov cx, OSLOADER_SEG ; CX = 缓冲区段地址 ; 清屏 ; for test, added by mingxuan 2020-9-15 ;pusha ;mov dx, 0184fh ; 右下角: (80, 50) ;int 10h ; int 10h ;popa _NEXT_DATA_CLUSTER: ; 根据簇号计算扇区号 DEC EAX DEC EAX XOR EBX,EBX ;MOV BL, BYTE [ BPB_SecPerClu ] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov bl, byte [fs:BPB_SecPerClu] ;modified by mingxuan 2020-9-13 mov bl, [BPB_SecPerClu] ;modified by mingxuan 2020-9-17 MUL EBX ;ADD EAX, DATA_START_SECTOR ;deleted by mingxuan 2020-9-17 ADD EAX, [DATA_START_SECTOR] ;modified by mingxuan 2020-9-17 MOV DWORD[ BP - DAP_SECTOR_LOW ], EAX ;MOV BL , BYTE [BPB_SecPerClu] ;mov bl, byte [fs:BPB_SecPerClu] ;modified by mingxuan 2020-9-13 mov bl, byte [BPB_SecPerClu] ;modified by mingxuan 2020-9-17 ; 设置缓冲区 MOV WORD [ BP - DAP_BUFFER_SEG ], CX MOV WORD [ BP - DAP_BUFFER_OFF ], OSLOADER_SEG_OFF _NEXT_DATA_SECTOR: ; 读取簇中的每个扇区(内层循环) ; 注意 : 通过检查文件大小，可以避免读取最后一个不满簇的所有大小 call ReadSector ; 更新地址，继续读取 ;MOV AX, WORD [BPB_BytesPerSec] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov ax, word [fs:BPB_BytesPerSec] ;modified by mingxuan 2020-9-13 mov ax, word [BPB_BytesPerSec] ;modified by mingxuan 2020-9-17 ADD WORD [BP - DAP_BUFFER_OFF], ax INC DWORD [BP - DAP_SECTOR_LOW] ; 递增扇区号 DEC BL ; 内层循环计数 JNZ _NEXT_DATA_SECTOR ;for test, added by mingxuan 2020-9-10 ;call DispStr ; ;JMP $ ;for test, added by mingxuan 2020-9-10 ; 更新读取下一个簇的缓冲区地址 ;MOV CL, BYTE [ BPB_SecPerClu ] ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov cl, byte [fs:BPB_SecPerClu] ;modified by mingxuan 2020-9-13 mov cl, [BPB_SecPerClu] ;modified by mingxuan 2020-9-17 ;MOV AX, WORD [BPB_BytesPerSec] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov ax, word [fs:BPB_BytesPerSec] ;modified by mingxuan 2020-9-13 mov ax, [BPB_BytesPerSec] ;modified by mingxuan 2020-9-17 SHR AX, 4 MUL CL ADD AX, WORD [ BP - DAP_BUFFER_SEG ] MOV CX, AX ; 保存下一个簇的缓冲区段地址 ;==================================================================== ; 检查是否还有下一个簇(读取FAT表的相关信息) ; LET N = 数据簇号 ; THUS FAT_BYTES = N*4 (FAT32) ; FAT_SECTOR = FAT_BYTES / BPB_BytesPerSec ; FAT_OFFSET = FAT_BYTES % BPB_BytesPerSec ;==================================================================== ; 计算FAT所在的簇号和偏移 MOV EAX,DWORD [BP - CURRENT_CLUSTER] XOR EDX,EDX SHL EAX,2 XOR EBX,EBX ;MOV BX,WORD [ BPB_BytesPerSec ] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ; mov bx, word [fs:BPB_BytesPerSec] ;modified by mingxuan 2020-9-13 mov bx, [BPB_BytesPerSec] ;modified by mingxuan 2020-9-17 DIV EBX ; EAX = Sector EDX = Offset ; 计算FAT表的起始扇区号 ; added by mingxuan 2020-9-17 ;mov ebx, dword [ fs:OffsetOfActiPartStartSec ] ;add bx, word [ fs:BPB_RsvdSecCnt ] ; 设置int 13h读取的绝对扇区号 ;ADD EAX, FAT_START_SECTOR ;deleted by mingxuan 2020-9-17 ADD EAX, [FAT_START_SECTOR] ;modified by mingxuan 2020-9-17 ;add eax, ebx ;modified by mingxuan 2020-9-17 MOV DWORD [ BP - DAP_SECTOR_LOW ], EAX ; 设置int 13h写入内存的缓冲区地址 MOV WORD [BP - DAP_BUFFER_SEG ], 01000H MOV WORD [BP - DAP_BUFFER_OFF ], DATA_BUF_OFF ; 读取扇区 ; 把FAT表读进内存 CALL ReadSector ; 检查下一个簇 MOV DI,DX ADD DI,DATA_BUF_OFF MOV EAX,DWORD[DI] ; EAX = 下一个要读的簇号 AND EAX,CLUSTER_MASK MOV DWORD[ BP - CURRENT_CLUSTER ],EAX CMP EAX,CLUSTER_LAST ; CX >= 0FFFFFF8H，则意味着没有更多的簇了 ;for test, added by mingxuan 2020-9-10 ;call DispStr ; ;JMP $ ;for test, added by mingxuan 2020-9-10 ; 清屏 ; for test, added by mingxuan 2020-9-15 ;pusha ;mov dx, 0184fh ; 右下角: (80, 50) ;int 10h ; int 10h ;popa JB _NEXT_DATA_CLUSTER _RUN_LOADER: ;mov dl, [BS_DriveNum] ;deleted by mingxuan 2020-9-13 ;mov es, BaseOfBoot ;modified by mingxuan 2020-9-13 ;mov dl, [fs:BS_DriveNum] ;modified by mingxuan 2020-9-13 mov dl, [BS_DriveNum] ;modified by mingxuan 2020-9-17 ;for test, added by mingxuan 2020-9-10 ;call DispStr ; ;jmp $ ;for test 2020-9-10, mingxuan ; 清屏 ; for test, added by mingxuan 2020-9-15 ;pusha ;mov dx, 0184fh ; 右下角: (80, 50) ;int 10h ; int 10h ;popa jmp OSLOADER_SEG : OSLOADER_SEG_OFF LoaderName db "LOADER BIN" ; 第二阶段启动程序 FDOSLDR.BIN ; for display ; added by mingxuan 2020-9-4 ;TestMessage: db "#" ; 27字节, 不够则用空格补齐. 序号 0 ; for display ; added by mingxuan 2020-9-4 ;DispStr: ; pusha ; mov ax, TestMessage ; mov bp, ax ; mov cx, 1 ; mov ax, 01301h ; AH = 13, AL = 01h ; mov bx, 0007h ; 页号为0(BH = 0) 黑底白字(BL = 07h) ; int 10h ; int 10h ; popa ; ret times 510-($-$$) db 0 ; 填充剩下的空间，使生成的二进制代码恰好为512字节 dw 0xaa55 ; 结束标志