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ORG 0x7C00 |
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BITS 16 |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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; SLRboot |
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; Bootloader for SingOS |
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; version 0.2.0.0-exp |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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cli |
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mov [disk_identifier], dl |
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mov ax, 0x1000 |
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mov ss, ax |
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mov sp, 0xb000 |
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mov ax, 0 |
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mov ds, ax |
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mov es, ax |
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sti |
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mov si, 0x7c00 |
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mov di, 0x600 |
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mov cx, 0x200 |
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rep movsb |
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mov bx, relocated |
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sub bx, 0x7600 ; Calculate the offset. |
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push bx |
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retf ; Return far |
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;jmp long 0:bx |
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relocated: |
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mov si, message ; Put address of the null-terminated string to output into 'si' |
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call print ; Call our string-printing routine |
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;mov ax, 0x0050 |
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;mov es, ax ;Section to write into |
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;mov ah, 0x2 ;Read sectors from drive |
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;mov al, 0x08 ;Number of sectors to read (31 * 512 = 15872 bytes) |
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;mov ch, 0x0 ;Low 8 bits of cylinder |
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;mov cl, 0x11 ;First sector to read (bits 0-5), upper bits of cylinder (bits 6-7) |
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;mov dh, 0x0 ;Head number |
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;mov dl, [disk_identifier] ;Drive number |
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;mov bx, 0x0000 ;Offset into section |
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;int 0x13 ;Low level disk services |
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mov ah, 2 |
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mov al, 0x08 |
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mov bx, 0x7c00 |
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mov BYTE dl, [disk_identifier] |
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mov BYTE dh, [partition_2.start_CHS + 1] ;byte [si + 1] |
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mov BYTE cl, [partition_2.start_CHS + 2] |
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mov BYTE ch, [partition_2.start_CHS] ;First sector to read (bits 0-5), upper bits of cylinder (bits 6-7) |
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int 0x13 |
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;mov ax, 0x0 |
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;mov ds, ax |
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mov ax, 89 ; lba adress |
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jmp long 0x0:0x7c00 |
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cli |
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hlt |
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%IF 1 |
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cli |
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jmp long 0x0000:start |
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start: |
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xor ax, ax |
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mov ds, ax |
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mov es, ax |
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mov ss, ax |
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mov [disk_identifier], dl |
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; initialize stack |
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; Set up 4K stack after this bootloader |
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; [Remember: Effective Address = Segment*16 + Offset] |
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mov ax, 0x7C0 ; Set 'ax' equal to the location of this bootloader divided by 16 |
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add ax, 0x20 ; Skip over the size of the bootloader divided by 16 |
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mov ss, ax ; Set 'ss' to this location (the beginning of our stack region) |
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mov sp, 8192 ; Set 'ss:sp' to the top of our 8K stack |
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sti |
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mov si, message ; Put address of the null-terminated string to output into 'si' |
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call print ; Call our string-printing routine |
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mov si, enter_debug_mode |
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call print |
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call printCRLF |
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;%IF 0 |
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; here goes wait call, for the user to enter debug mode. |
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; Wating for 2 seconds: |
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mov ah, 0x86 ; code for waiting interupt call |
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mov cx, 0x001e ; high count of microseconds |
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mov dx, 0x8480 ; low count |
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int 0x15 |
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.busy_wait_for_key: |
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xor ax, ax |
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mov ah, 0x01 ; BIOS call to wait for key |
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int 0x16 |
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jnz debug_mode |
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; entering system check: |
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mov si, enter_system_check |
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mov si, sys_check_ok ; Put address of the null-terminated string to output into 'si' |
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call print ; Call our string-printing routine |
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mov si, boot_system ; Put address of the null-terminated string to output into 'si' |
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call print ; Call our string-printing routine |
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;This goes first as to now overwrite %ah and %al. |
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;mov ax, 0x0050 |
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;mov es, ax ;Section to write into |
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;mov ah, 0x2 ;Read sectors from drive |
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;mov al, 0x08 ;Number of sectors to read (31 * 512 = 15872 bytes) |
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;mov ch, 0x0 ;Low 8 bits of cylinder |
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;mov cl, 0x11 ;First sector to read (bits 0-5), upper bits of cylinder (bits 6-7) |
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;mov dh, 0x0 ;Head number |
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;mov dl, [disk_identifier] ;Drive number |
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;mov bx, 0x0000 ;Offset into section |
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;int 0x13 ;Low level disk services |
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;jnc notcarry |
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;mov si, error_str |
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;call print |
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;jmp endcarrycheck |
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notcarry: |
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;mov si, success_str |
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;call print |
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;call printCRLF |
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mov ax, 0x0 |
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mov ds, ax |
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mov ax, 89 ; lba adress |
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jmp 0x50:0x0000 ; Jump to the kernel |
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endcarrycheck: |
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cli ; Clear the Interrupt Flag (disable external interrupts) |
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hlt ; Halt the CPU (until the next external interrupt) |
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debug_mode: |
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mov si, .welcome_debug |
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call print |
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cli ; Clear the Interrupt Flag (disable external interrupts) |
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hlt |
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.welcome_debug db 'This is debug mode', 0 |
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;Routine for printing a 'ax' as hex |
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dumpax: |
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pusha ; save registers |
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mov bx, ax |
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mov ah, 0xE ; Teletype output |
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mov cx, 4 ; 4 nipples in a 16 bit word |
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.loop: |
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rol bx, 4 ; rotate to next nipple |
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mov al, bl ; we copy to al because we need to mask only the low 4 bits |
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and al, 1111b ; Do the masking |
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add al, '0' ; convert to ASCII |
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cmp al, '9' ; If we are greater than 9 ascii, we add 7 to make digit 10 be represented as 'A' |
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jbe .skip ; -|- |
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add al, 7 ; -|- |
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.skip: ; -|- |
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int 0x10 ; BIOS call 'output' |
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loop .loop |
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popa ; restore registers |
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ret |
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printCRLF: |
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mov ah, 0xE |
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mov al, 13 |
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int 0x10 |
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mov al, 10 |
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int 0x10 |
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ret |
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%ENDIF |
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; Routine for outputting string in 'si' register to screen |
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print: |
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mov ah, 0xE ; Specify 'int 0x10' 'teletype output' function |
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; [AL = Character, BH = Page Number, BL = Colour (in graphics mode)] |
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.printchar: |
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lodsb ; Load byte at address SI into AL, and increment SI |
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cmp al, 0 |
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je .done ; If the character is zero (NUL), stop writing the string |
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int 0x10 ; Otherwise, print the character via 'int 0x10' |
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jmp .printchar ; Repeat for the next character |
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.done: |
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ret |
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data: |
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message db 'SLRboot for SingOS! v0.2.0.0-exp',13,10,0 |
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enter_debug_mode db 'Press d to enter bootloader debug mode',13,10,0 |
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enter_system_check db 'Performing system check:',13,10,0 |
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sys_check_ok db 'System check ok', 13, 10, 0 |
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boot_system db 'Read SingOS from disk', 13, 10, 0 |
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error_str db 'Error', 0 |
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success_str db 'Success', 0 |
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disk_identifier db 0 |
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; Pad to 510 bytes (boot sector size minus 2) with 0s, and finish with the two-byte standard boot signature |
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times 446-($-$$) db 0 ; First partion entry |
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partition_1: |
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.active_partition db 0x00 |
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.start_CHS db 0x00, 0x00, 0x11;0x20, 0x21, 0x00 |
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.disk_type db 0x83 |
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.end_CHS db 0x8C, 0x3D, 0x0F |
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.start_LBA db 0x00, 0x08, 0x00, 0x00 |
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.size db 0x00, 0xC8, 0x03, 0x00 |
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partition_2: |
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.active_partition db 0x80 |
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.start_CHS db 0x8C, 0x3E, 0x0F |
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.disk_type db 0x83 |
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.end_CHS db 0xFF, 0xFF, 0xFF |
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.start_LBA db 0x00, 0xD0, 0x03, 0x00 |
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.size db 0x00, 0x28, 0x1C, 0x03 |
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partition_3: |
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.active_partition db 0x00 |
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.start_CHS db 0x00, 0x00, 0x00 |
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.disk_type db 0x00 |
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.end_CHS db 0x00, 0x00, 0x00 |
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.start_LBA db 0x00, 0x00, 0x00, 0x00 |
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.size db 0x00, 0x00, 0x00, 0x00 |
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partition_4: |
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.active_partition db 0x00 |
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.start_CHS db 0x00, 0x00, 0x00 |
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.disk_type db 0x00 |
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.end_CHS db 0x00, 0x00, 0x00 |
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.start_LBA db 0x00, 0x00, 0x00, 0x00 |
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.size db 0x00, 0x00, 0x00, 0x00 |
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times 510-($-$$) db 0 |
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dw 0xAA55 ; => 0x55 0xAA (little endian byte order) |
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; bootloder debug_mode goes here |
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times 8192-($-$$) db 0 |
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; mov si, 0x7be |
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; cmp byte [si], al |
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; jne 0x33 |
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; add si, 0x10 |
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; cmp si, 0x7fe |
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; jne 0x24 |
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; jmp 0x49 |
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; mov ah, 2 |
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; mov al, 1 |
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; mov bx, 0x7c00 |
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; mov dl, 0x80 |
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; mov dh, byte [si + 1] |
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; mov cx, word [si + 2] |
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; int 0x13 |
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; jmp long 0:0x7c00 |
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; jmp 0x49 |
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Reference in new issue