mkinitrd-6_3_2/isolinux/rawcon.inc

;
; writechr:	Write a single character in AL to the console without
;		mangling any registers.  This does raw console writes,
;		since some PXE BIOSes seem to interfere regular console I/O.
;
%if IS_ISOLINUX
writechr_full:
%else
writechr:
%endif
		pushfd
		push ds
		push cs
		pop ds
		test byte [UsingVGA], 08h
		jz .videook
		call vgaclearmode
.videook:
		call write_serial	; write to serial port if needed
		test byte [DisplayCon],01h	; Write to screen?
		jz .nothing

		pushad
		mov bh,[BIOS_page]
		push ax
                mov ah,03h              ; Read cursor position
                int 10h
		pop ax
		cmp al,8
		je .bs
		cmp al,13
		je .cr
		cmp al,10
		je .lf
		push dx
                mov bh,[BIOS_page]
		mov bl,07h		; White on black
		mov cx,1		; One only
		mov ah,09h		; Write char and attribute
		int 10h
		pop dx
		inc dl
		cmp dl,[VidCols]
		jna .curxyok
		xor dl,dl
.lf:		inc dh
		cmp dh,[VidRows]
		ja .scroll
.curxyok:	mov bh,[BIOS_page]
		mov ah,02h		; Set cursor position
		int 10h
.ret:		popad
.nothing:
		pop ds
		popfd
		ret
.scroll:	dec dh
		mov bh,[BIOS_page]
		mov ah,02h
		int 10h
		mov ax,0601h		; Scroll up one line
		mov bh,[ScrollAttribute]
		xor cx,cx
		mov dx,[ScreenSize]	; The whole screen
		int 10h
		jmp short .ret
.cr:		xor dl,dl
		jmp short .curxyok
.bs:		sub dl,1
		jnc .curxyok
		mov dl,[VidCols]
		sub dh,1
		jnc .curxyok
		xor dh,dh
		jmp short .curxyok
1	niro	532	;
2			; writechr: Write a single character in AL to the console without
3			; mangling any registers. This does raw console writes,
4			; since some PXE BIOSes seem to interfere regular console I/O.
5			;
6			%if IS_ISOLINUX
7			writechr_full:
8			%else
9			writechr:
10			%endif
11	niro	1133	pushfd
12	niro	532	push ds
13			push cs
14			pop ds
15	niro	1133	test byte [UsingVGA], 08h
16			jz .videook
17			call vgaclearmode
18			.videook:
19	niro	532	call write_serial ; write to serial port if needed
20			test byte [DisplayCon],01h ; Write to screen?
21			jz .nothing
22
23			pushad
24			mov bh,[BIOS_page]
25			push ax
26			mov ah,03h ; Read cursor position
27			int 10h
28			pop ax
29			cmp al,8
30			je .bs
31			cmp al,13
32			je .cr
33			cmp al,10
34			je .lf
35			push dx
36			mov bh,[BIOS_page]
37			mov bl,07h ; White on black
38			mov cx,1 ; One only
39			mov ah,09h ; Write char and attribute
40			int 10h
41			pop dx
42			inc dl
43			cmp dl,[VidCols]
44			jna .curxyok
45			xor dl,dl
46			.lf: inc dh
47			cmp dh,[VidRows]
48			ja .scroll
49			.curxyok: mov bh,[BIOS_page]
50			mov ah,02h ; Set cursor position
51	niro	1133	int 10h
52	niro	532	.ret: popad
53			.nothing:
54	niro	1133	pop ds
55	niro	532	popfd
56			ret
57			.scroll: dec dh
58			mov bh,[BIOS_page]
59			mov ah,02h
60			int 10h
61			mov ax,0601h ; Scroll up one line
62			mov bh,[ScrollAttribute]
63			xor cx,cx
64			mov dx,[ScreenSize] ; The whole screen
65			int 10h
66			jmp short .ret
67			.cr: xor dl,dl
68			jmp short .curxyok
69			.bs: sub dl,1
70			jnc .curxyok
71			mov dl,[VidCols]
72			sub dh,1
73			jnc .curxyok
74			xor dh,dh
75			jmp short .curxyok