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Re: [Qemu-devel] [Qemu-trivial] [PATCH v2] SGABIOS: fix wrong video attr
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [Qemu-trivial] [PATCH v2] SGABIOS: fix wrong video attrs for int 10h, ah==13h |
Date: |
Fri, 10 Mar 2017 08:53:00 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 |
On 09/03/2017 19:48, Herbie Robinson wrote:
> Fix Bug #1670509: wrong video attrs for int 10h, ah==13h
> The subroutine set_cursor_position is trashing %bx.
> Unfortunately, %bl contains the video attribute for write_string.
>
> The fix saves %bx in the function prolog and restores it in
> the epilog. Also, remove save and restore in set_current_cursor,
> because set_cursor_position does it.
>
> Signed-off-by: Herbie Robinson <address@hidden>
> ---
> Removed incorrect code deletions from set_current_cursor.
You should update the commit message too.
Laurent
>
> sgabios.S | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/sgabios.S b/sgabios.S
> index 275d063..96c4e23 100644
> --- a/sgabios.S
> +++ b/sgabios.S
> @@ -1728,6 +1728,7 @@ write_string_tail:
>
> set_cursor_position:
> pushw %ax
> + pushw %bx
> pushw %ds
> pushw $BDA_SEG
> popw %ds /* ds = 0x40 */
> @@ -1738,6 +1739,7 @@ set_cursor_position:
> movw %ax, %bx /* bx = cursor save offset */
> movw %dx, (%bx) /* save new cursor value */
> popw %ds
> + popw %bx
> popw %ax
> ret
>
>