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authorH. Peter Anvin <hpa@zytor.com>2007-08-23 09:28:42 -0700
committerH. Peter Anvin <hpa@zytor.com>2007-08-23 13:03:25 -0700
commit71351b98b9be6a867aa00276d67716c0728cfff7 (patch)
tree9ab25a995c333d21274403ca7302449d51544b26 /arch
parentb015124e562a040f7faf361c72e8f5f457ac6cf5 (diff)
[x86 setup] Make sure AH=00h when setting a video mode
Passing a u8 into a register doesn't mean gcc will zero-extend it. Also, don't depend on thhe register not to change. Per bug report from Saul Tamari. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/boot/video-vga.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/i386/boot/video-vga.c b/arch/i386/boot/video-vga.c
index d660e608cd5..aef02f9ec0c 100644
--- a/arch/i386/boot/video-vga.c
+++ b/arch/i386/boot/video-vga.c
@@ -73,9 +73,10 @@ static u8 vga_set_basic_mode(void)
mode = 3;
/* Set the mode */
+ ax = mode;
asm volatile(INT10
- : : "a" (mode)
- : "ebx", "ecx", "edx", "esi", "edi");
+ : "+a" (ax)
+ : : "ebx", "ecx", "edx", "esi", "edi");
do_restore = 1;
return mode;
}