Move the cursor position rightward after rendering the character,
not before. This avoids complications that arise when the recursive
console_putc call has to wrap the line and/or scroll the display.
This also fixes the linewrap bug that crops off the rightmost column.
When the cursor is at the bottom of the display, a linefeed will not
move the cursor position further downward. Instead, the display scrolls
upward. Avoid the repeated add/subtract sequence by way of a single
subtraction at the initialization of console_struct_num_rows.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxx>
---
arch/m68k/kernel/head.S | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S
index 852255cf60de..d0d77b1adbde 100644
--- a/arch/m68k/kernel/head.S
+++ b/arch/m68k/kernel/head.S
@@ -3400,6 +3400,7 @@ L(console_clear_loop):
movel %d4,%d1 /* screen height in pixels */
divul %a0@(FONT_DESC_HEIGHT),%d1 /* d1 = max num rows */
+ subil #1,%d1 /* row range is 0 to num - 1 */
movel %d0,%a2@(Lconsole_struct_num_columns)
movel %d1,%a2@(Lconsole_struct_num_rows)
@@ -3546,15 +3547,14 @@ func_start console_putc,%a0/%a1/%d0-%d7
cmpib #10,%d7
jne L(console_not_lf)
movel %a0@(Lconsole_struct_cur_row),%d0
- addil #1,%d0
- movel %d0,%a0@(Lconsole_struct_cur_row)
movel %a0@(Lconsole_struct_num_rows),%d1
cmpl %d1,%d0
jcs 1f
- subil #1,%d0
- movel %d0,%a0@(Lconsole_struct_cur_row)
console_scroll
+ jra L(console_exit)
1:
+ addil #1,%d0
+ movel %d0,%a0@(Lconsole_struct_cur_row)
jra L(console_exit)
L(console_not_lf):
@@ -3581,12 +3581,6 @@ L(console_not_cr):
*/
L(console_not_home):
movel %a0@(Lconsole_struct_cur_column),%d0
- addql #1,%a0@(Lconsole_struct_cur_column)
- movel %a0@(Lconsole_struct_num_columns),%d1
- cmpl %d1,%d0
- jcs 1f
- console_putc #'\n' /* recursion is OK! */
-1:
movel %a0@(Lconsole_struct_cur_row),%d1
/*
@@ -3633,6 +3627,23 @@ L(console_do_font_scanline):
addq #1,%d1
dbra %d7,L(console_read_char_scanline)
+ /*
+ * Register usage in the code below:
+ * a0 = pointer to console globals
+ * d0 = cursor column
+ * d1 = cursor column limit
+ */
+
+ lea %pc@(L(console_globals)),%a0
+
+ movel %a0@(Lconsole_struct_cur_column),%d0
+ addil #1,%d0
+ movel %d0,%a0@(Lconsole_struct_cur_column) /* Update cursor pos */
+ movel %a0@(Lconsole_struct_num_columns),%d1
+ cmpl %d1,%d0
+ jcs L(console_exit)
+ console_putc #'\n' /* Line wrap using tail recursion */
+
L(console_exit):
func_return console_putc
--
2.45.3
