67 lines
1.3 KiB
NASM
67 lines
1.3 KiB
NASM
[ORG 0x7c00]
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[BITS 16]
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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 ah, 0x42
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mov si, addr_packet
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int 0x13
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jnc entry
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push 0xb800
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pop es
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xor di, di
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mov si, string
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mov cx, 10
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mov ah, 0x7
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err_print:
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lodsb
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stosw
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loop err_print
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hlt_loop:
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hlt
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jmp hlt_loop
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entry:
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cli ; no interrupts
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xor ax,ax
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mov ds, ax
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lgdt [gdt_desc] ; load gdt register
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mov eax, cr0 ; set pmode bit
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or al, 1
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mov cr0, eax
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jmp 08h:Pmode
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[BITS 32]
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Pmode:
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mov ax, 0x10
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mov ds, ax
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mov es, ax
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mov esi, 0x8000
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mov edi, 0x100000
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mov ecx, 0x10000
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rep movsb
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jmp 08h:0x100000
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gdt_desc:
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dw gdt_end - gdt
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dd gdt
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gdt:
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gdt_null: dq 0
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gdt_code: dw 0xFFFF, 0 ; bits 0-15 limit (4GB), bits 0-15 base address
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db 0 ; bits 16-23 base address
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db 10011010b ; access byte
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db 11001111b ; bits 16-19 limit (4GB), 4 bits flags
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db 0 ; bits 24-31 base address
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gdt_data: dw 0xFFFF, 0 ; bits 0-15 limit (4GB), bits 0-15 base address
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db 0 ; bits 16-23 base address
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db 10010010b ; access byte
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db 11001111b ; bits 16-19 limit (4GB), 4 bits flags
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db 0 ; bits 24-31 base address
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gdt_end:
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string: db 'DISK ERROR'
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addr_packet:
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db 0x10, 0x00 ; size, reserved
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dw 0x39 ; blocks
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dd 0x8000 ; transfer buffer
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dq 1 ; start block
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