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|
;
; 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
|
