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https://github.com/Tom-on64/kern.git
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Tom-on
726247a4f2
If you want to build the assembly version, run the buildAsm.sh script Currently just setting up the bootloader.
99 lines
1.9 KiB
NASM
99 lines
1.9 KiB
NASM
[org 0x7c00]
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[bits 16]
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[global start]
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start:
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; Setup
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xor ax, ax
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mov es, ax
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mov ds, ax
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mov bp, 0x7c00
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mov sp, bp
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; Save drive number
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mov byte [driveNumber], dl
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; Print boot message
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mov si, bootMsg
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call print
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mov dl, byte [driveNumber]
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call printHex
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mov si, newline
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call print
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; Read filetable from disk
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mov bx, FILETAB_LOC ; Filetable location in memory
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mov es, bx
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xor bx, bx
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mov ah, 2 ; Read from disk
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mov al, 1 ; Read 1 sector (512B)
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mov dl, byte [driveNumber] ; Drive number
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mov ch, 0 ; Cylinder
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mov dh, 0 ; Head
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mov cl, 2 ; Sector
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int 0x13 ; INT 0x13 - Disk operations
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jc readFail ; CF will be set if the read fails
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; Read filetable from disk
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mov bx, KERNEL_LOC ; Filetable location in memory
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mov es, bx
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xor bx, bx
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mov ah, 2 ; Read from disk
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mov al, 4 ; Read 4 sectors (2kB)
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mov dl, byte [driveNumber] ; Drive number
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mov ch, 0 ; Cylinder
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mov dh, 0 ; Head
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mov cl, 3 ; Sector
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int 0x13 ; INT 0x13 - Disk operations
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jc readFail ; CF will be set if the read fails
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; Setup segmentation
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mov ax, KERNEL_LOC
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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; Setup stack
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mov bp, 0xffff
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mov sp, bp
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mov ax, 0x9000
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mov ss, ax
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mov bl, byte [driveNumber]
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; Setup video mode
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mov ax, 0x0003
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int 0x10
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mov ah, 0x0b
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mov bx, 0x0001
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int 0x10
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; Far jump to the kernel (never returns)
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jmp KERNEL_LOC:0x0000
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readFail:
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mov si, diskErrorMsg
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call print
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cli
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hlt
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%include "./src/lib/print.asm"
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driveNumber: db 0
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bootMsg: db ENDL, "Booting kern.", ENDL, "Booting from drive ", 0
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diskErrorMsg: db "Disk Error!", ENDL, 0
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FILETAB_LOC equ 0x1000
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KERNEL_LOC equ 0x2000
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times 510-($-$$) db 0
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dw 0xaa55
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