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[Qemu-trivial] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah
From: |
Herbie Robinson |
Subject: |
[Qemu-trivial] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h |
Date: |
Fri, 10 Mar 2017 10:54:55 -0500 |
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.
Signed-off-by: Herbie Robinson <address@hidden>
---
Removed incorrect code deletions from set_current_cursor.
Removed explanation of same from the commit message.
BTW, I didn't see any test cases for this code, but if they exist
and somebody points me at them, I should be able to generate a
very small qcow2 file that demonstrates the problem.
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
--
1.8.3.1
- [Qemu-trivial] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h,
Herbie Robinson <=