[PATCH v3 2/3] m68k: Avoid pointless recursion in debug console rendering
From: Finn Thain
Date: Thu Mar 27 2025 - 18:44:39 EST
The recursive call to console_putc to effect a carriage return is
needlessly slow and complicated. Instead, just clear the column counter
directly. Setup %a0 earlier to avoid a repeated comparison.
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxx>
---
arch/m68k/kernel/head.S | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S
index 9bd8adaa756d..49e079b0d0b5 100644
--- a/arch/m68k/kernel/head.S
+++ b/arch/m68k/kernel/head.S
@@ -3533,19 +3533,16 @@ func_start console_putc,%a0/%a1/%d0-%d7
tstl %pc@(L(console_font))
jeq L(console_exit)
+ lea %pc@(L(console_globals)),%a0
+
/* Output character in d7 on console.
*/
movel ARG1,%d7
cmpib #'\n',%d7
- jbne 1f
+ jne L(console_not_lf)
- /* A little safe recursion is good for the soul */
- console_putc #'\r'
-1:
- lea %pc@(L(console_globals)),%a0
+ clrl %a0@(Lconsole_struct_cur_column) /* implicit \r */
- cmpib #10,%d7
- jne L(console_not_lf)
movel %a0@(Lconsole_struct_cur_row),%d0
movel %a0@(Lconsole_struct_num_rows),%d1
cmpl %d1,%d0
--
2.45.3