mkinitrd-magellan/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	;
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	pushfd
12	push ds
13	push cs
14	pop ds
15	test byte [UsingVGA], 08h
16	jz .videook
17	call vgaclearmode
18	.videook:
19	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	int 10h
52	.ret: popad
53	.nothing:
54	pop ds
55	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