| Message ID | 20170309165120.960B540827A6@vostest4.mno.stratus.com |
|---|---|
| State | New |
| Headers | show |
On 07/03/2017 02:30, herbierobinson 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: herbierobinson <Herbie.Robinson@stratus.com> > --- > sgabios.S | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/sgabios.S b/sgabios.S > index 275d063..da5acc2 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 > > @@ -1752,12 +1754,10 @@ set_cursor_position: > > set_current_cursor: > pushw %ds > - pushw %bx > pushw $BDA_SEG > popw %ds /* ds = 0x40 */ > movb BDA_ACTIVE_PAGE, %bh Well, we are trashing %bh here, I think the push/pop %bx is needed. [comment says "all registers preserved except flags"] > call set_cursor_position > - popw %bx > popw %ds > ret > >
diff --git a/sgabios.S b/sgabios.S index 275d063..da5acc2 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 @@ -1752,12 +1754,10 @@ set_cursor_position: set_current_cursor: pushw %ds - pushw %bx pushw $BDA_SEG popw %ds /* ds = 0x40 */ movb BDA_ACTIVE_PAGE, %bh call set_cursor_position - popw %bx popw %ds ret
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: herbierobinson <Herbie.Robinson@stratus.com> --- sgabios.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)