mkinitrd-6_1_11/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
		push ds
		push cs
		pop ds
		call write_serial	; write to serial port if needed
		pushfd
		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:
		popfd
		pop ds
		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	;
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	push ds
12	push cs
13	pop ds
14	call write_serial ; write to serial port if needed
15	pushfd
16	test byte [DisplayCon],01h ; Write to screen?
17	jz .nothing
18
19	pushad
20	mov bh,[BIOS_page]
21	push ax
22	mov ah,03h ; Read cursor position
23	int 10h
24	pop ax
25	cmp al,8
26	je .bs
27	cmp al,13
28	je .cr
29	cmp al,10
30	je .lf
31	push dx
32	mov bh,[BIOS_page]
33	mov bl,07h ; White on black
34	mov cx,1 ; One only
35	mov ah,09h ; Write char and attribute
36	int 10h
37	pop dx
38	inc dl
39	cmp dl,[VidCols]
40	jna .curxyok
41	xor dl,dl
42	.lf: inc dh
43	cmp dh,[VidRows]
44	ja .scroll
45	.curxyok: mov bh,[BIOS_page]
46	mov ah,02h ; Set cursor position
47	int 10h
48	.ret: popad
49	.nothing:
50	popfd
51	pop ds
52	ret
53	.scroll: dec dh
54	mov bh,[BIOS_page]
55	mov ah,02h
56	int 10h
57	mov ax,0601h ; Scroll up one line
58	mov bh,[ScrollAttribute]
59	xor cx,cx
60	mov dx,[ScreenSize] ; The whole screen
61	int 10h
62	jmp short .ret
63	.cr: xor dl,dl
64	jmp short .curxyok
65	.bs: sub dl,1
66	jnc .curxyok
67	mov dl,[VidCols]
68	sub dh,1
69	jnc .curxyok
70	xor dh,dh
71	jmp short .curxyok
72