since we cannot trust multiboot structures to be there we'll just yolo text mode
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					 1 changed files with 74 additions and 117 deletions
				
			
		
							
								
								
									
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			@ -12,9 +12,9 @@ MB_HEADER_FLAGS      equ MB_PAGE_ALIGN or MB_MEMORY_INFO or MB_VIDEO_REQUEST or
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MB_CHECKSUM          equ -(MB_HEADER_MAGIC + MB_HEADER_FLAGS)
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;; safe modes according to https://wiki.osdev.org/VESA_Video_Modes
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VWIDTH  equ 640 ; 640/720
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VHEIGHT equ 480 ; 480
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VDEPTH  equ 32  ; 24/32
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VWIDTH  equ 80 ; 640/720
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VHEIGHT equ 25 ; 480
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VDEPTH  equ 0  ; 24/32, zero in textmode
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multiboot:
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	dd MB_HEADER_MAGIC
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			@ -26,7 +26,7 @@ multiboot:
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	dd bss_end	; bss end address
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	dd start	; entry address
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	dd 0	; video mode_type (0:fb, 1:txt) (set flags[2]!)
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	dd 1	; video mode_type (0:fb, 1:txt) (set flags[2]!)
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	dd VWIDTH	; video width
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	dd VHEIGHT	; video height
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	dd VDEPTH	; video depth
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			@ -39,132 +39,86 @@ start:
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	;push ebx ; mboot info struct addr
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	;push eax ; 0x2BADB002
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	;mov [mbootmagic], eax
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	mov [mbootmagic], eax
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	;mov [mbootaddr], ebx
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	; store video info
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	mov ecx, [ebx+88]
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	mov [fb.addr], ecx
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	mov ecx, [ebx+98]
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	mov [fb.pitch], ecx
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	mov ecx, [ebx+100]
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	mov [fb.width], ecx
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	mov ecx, [ebx+104]
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	mov [fb.height], ecx
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	mov cl, [ebx+108]
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	mov [fb.depth], cl
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	call con_disable_cursor
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	call conclear
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	; calculate bytespp
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	movzx eax, cl
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	mov cl, 8
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	div byte cl
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	mov [fb.bytespp], al
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	mov esi, msg.roskainiting
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	call conwriteln
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	; color component positions
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	mov cl, [ebx+110+2]
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	mov [fb.rpos], cl
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	;mov cl, [ebx+111]
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	;mov [fb.rmasksize], cl
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	mov cl, [ebx+112+2]
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	mov [fb.gpos], cl
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	;mov cl, [ebx+113]
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	;mov [fb.gmasksize], cl
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	mov cl, [ebx+114+2]
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	mov [fb.bpos], cl
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	;mov cl, [ebx+115]
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	;mov [fb.bmasksize], cl
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testpixels:
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	; construct pixel R
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	mov al, 0xff ;r
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	mov ah, 0x00 ;g
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	mov ch, 0x00 ;b
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	xor edx, edx ;final pixel
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	;ebx is temp pixel
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	movzx ebx, al
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	mov cl, [fb.rpos]
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	shl ebx, cl
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	;and ebx, [fb.rmasksize]
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	or edx, ebx
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	movzx ebx, ah
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	mov cl, [fb.gpos]
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	shl ebx, cl
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	;and ebx, [fb.gmasksize]
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	or edx, ebx
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	movzx ebx, ch
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	mov cl, [fb.bpos]
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	shl ebx, cl
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	;and ebx, [fb.bmasksize]
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	or edx, ebx
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	mov ecx, [fb.addr]
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	mov [ecx], edx
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	; construct pixel G
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	mov al, 0x00 ;r
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	mov ah, 0xff ;g
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	mov ch, 0x00 ;b
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	xor edx, edx ;final pixel
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	;ebx is temp pixel
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	movzx ebx, al
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	mov cl, [fb.rpos]
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	shl ebx, cl
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	;and ebx, [fb.rmasksize]
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	or edx, ebx
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	movzx ebx, ah
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	mov cl, [fb.gpos]
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	shl ebx, cl
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	;and ebx, [fb.gmasksize]
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	or edx, ebx
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	movzx ebx, ch
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	mov cl, [fb.bpos]
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	shl ebx, cl
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	;and ebx, [fb.bmasksize]
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	or edx, ebx
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	mov ecx, [fb.addr]
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	movzx ebx, [fb.bytespp]
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	add ecx, ebx
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	mov [ecx], edx
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	; construct pixel B
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	mov al, 0x00 ;r
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	mov ah, 0x00 ;g
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	mov ch, 0xff ;b
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	xor edx, edx ;final pixel
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	;ebx is temp pixel
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	movzx ebx, al
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	mov cl, [fb.rpos]
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	shl ebx, cl
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	;and ebx, [fb.rmasksize]
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	or edx, ebx
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	movzx ebx, ah
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	mov cl, [fb.gpos]
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	shl ebx, cl
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	;and ebx, [fb.gmasksize]
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	or edx, ebx
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	movzx ebx, ch
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	mov cl, [fb.bpos]
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	shl ebx, cl
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	;and ebx, [fb.bmasksize]
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	or edx, ebx
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	mov ecx, [fb.addr]
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	movzx ebx, [fb.bytespp]
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	add ecx, ebx
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	add ecx, ebx
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	mov [ecx], edx
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	;mov dword [edx], 0xff00ff00
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testpixels_end:
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hang:
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	;cli
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	.loop:
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		;hlt
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		jmp .loop
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error:
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	mov dword [0xFD000000], 0x00FF0000
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	jmp hang
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;give character in AL
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conputchar:
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	mov ah, [txtbuf.col]
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	mov dx, ax
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	; dx has the whole character cell now
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	xor eax, eax
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	mov al, [txtbuf.y]
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	mov bl, 25
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	mul bl
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	movzx bx, [txtbuf.x]
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	add ax, bx
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	add ax, ax
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	add eax, 0xb8000
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	mov [eax], dx
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	cmp bl, 24
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	je connewline
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	inc bl
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	mov [txtbuf.x], bl
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	ret
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conwriteln:
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	lodsb
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	cmp al, 0
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	je connewline
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	call conputchar
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	jmp conwriteln
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connewline:
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	mov [txtbuf.x], 0
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	mov al, [txtbuf.y]
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	cmp al, 24
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	je conscroll
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	inc al
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	mov [txtbuf.y], al
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	ret
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conscroll:
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	ret
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conclear:
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	mov ecx, 80*25
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	mov edi, 0xb8000
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	mov ah, 0x07
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	mov al, 0
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	rep stosw
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	mov [txtbuf.col], ah
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	mov [txtbuf.x], 0
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	mov [txtbuf.y], 0
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	ret
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con_disable_cursor:
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	mov dx, 0x3D4
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	mov al, 0xA	; low cursor shape register
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	out dx, al
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	inc dx
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	mov al, 0x20	; bits 6-7 unused, bit 5 disables the cursor, bits 0-4 control the cursor shape
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	out dx, al
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	ret
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mbootaddr: dd 0
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mbootmagic: dd 0
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txtbuf:
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	.x db 0
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	.y db 0
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	.col db 0x07 ;gray on black
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fb:
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	.addr dd 0
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	.pitch dd 0
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			@ -179,6 +133,9 @@ fb:
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	.bpos db 0
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	;.bmasksize db 0
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msg:
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	.roskainiting db "rOSka initializing...", 0
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align 4096
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bss_start:
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align 4096
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