On 08.04.2013 19:17, Vladimir 'φ-coder/phcoder' Serbinenko wrote: > On 21.02.2013 17:20, Andrey Borzenkov wrote: > >> BIOS console wrapped line at 79 characters. It became the issue >> after recent changes when extra column for scrolling indications was >> removed. The effect was that up/down arrows were printed in the first >> column of the next line. >> >> May be it would be easier to simply use INT10 AH=13. Available >> documentation indicates that it is available since 1986, so I guess >> any system that exists today should implement it. >> > > I need to look how we ended up with the current code. It doesn't match > its comment which details an algorithm working for any screen dimensions > while current code assumes a fixed width. Another corner question is a > possibility of usage of vga_text and keep console to the bare minimum. > Does anyone have information about BIOSes redirecting their output? > The age of the function is no argument about their availability. Loads > of functions are not implemented or broken in modern BIOSes. More or > less the only guarantee of function working on all BIOSes is if BIOS > uses them in a normal bootpath. >
The code was the same since it was (re)written in 2002 for GRUB Legacy.
Your code and original make the same assumptions, so the patch is good.
Could you make a membership request on savannah so you can commit
patches yourself once they're approved?
>> Signed-off-by: Andrey Borzenkov <arvidj...@gmail.com>
>>
>> ---
>> grub-core/term/i386/pc/console.c | 21 ++++++++-------------
>> 1 file changed, 8 insertions(+), 13 deletions(-)
>>
>> diff --git a/grub-core/term/i386/pc/console.c
>> b/grub-core/term/i386/pc/console.c
>> index 2aa1943..358611a 100644
>> --- a/grub-core/term/i386/pc/console.c
>> +++ b/grub-core/term/i386/pc/console.c
>> @@ -86,13 +86,9 @@ grub_console_gotoxy (struct grub_term_output *term
>> __attribute__ ((unused)),
>> * Put the character C on the console. Because GRUB wants to write a
>> * character with an attribute, this implementation is a bit tricky.
>> * If C is a control character (CR, LF, BEL, BS), use INT 10, AH = 0Eh
>> - * (TELETYPE OUTPUT). Otherwise, save the original position, put a space,
>> - * save the current position, restore the original position, write the
>> - * character and the attribute, and restore the current position.
>> - *
>> - * The reason why this is so complicated is that there is no easy way to
>> - * get the height of the screen, and the TELETYPE OUTPUT BIOS call doesn't
>> - * support setting a background attribute.
>> + * (TELETYPE OUTPUT). Otherwise, use INT 10, AH = 9 to write character
>> + * with attributes and advance cursor. If we are on the last column,
>> + * let BIOS to wrap line correctly.
>> */
>> static void
>> grub_console_putchar_real (grub_uint8_t c)
>> @@ -112,19 +108,18 @@ grub_console_putchar_real (grub_uint8_t c)
>> /* get the current position */
>> pos = grub_console_getxy (NULL);
>>
>> + /* write the character with the attribute */
>> + int10_9 (c, 1);
>> +
>> /* check the column with the width */
>> if ((pos & 0xff00) >= (79 << 8))
>> {
>> grub_console_putchar_real (0x0d);
>> grub_console_putchar_real (0x0a);
>> - /* get the current position */
>> - pos = grub_console_getxy (NULL);
>> }
>> + else
>> + grub_console_gotoxy (NULL, ((pos & 0xff00) >> 8) + 1, (pos & 0xff));
>>
>> - /* write the character with the attribute */
>> - int10_9 (c, 1);
>> -
>> - grub_console_gotoxy (NULL, ((pos & 0xff00) >> 8) + 1, (pos & 0xff));
>> }
>>
>> static void
>
>
>
signature.asc
Description: OpenPGP digital signature
_______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
