From: Finn Thain <fthain@linux-m68k.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 2/3] m68k: Avoid pointless recursion in debug console rendering
Date: Fri, 28 Mar 2025 09:39:55 +1100 [thread overview]
Message-ID: <a6104f41918bed4fd17f92c45df94ac7a5d30e40.1743115195.git.fthain@linux-m68k.org> (raw)
In-Reply-To: <cover.1743115195.git.fthain@linux-m68k.org>
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@linux-m68k.org>
---
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
next prev parent reply other threads:[~2025-03-27 22:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-27 22:39 [PATCH v3 0/3] m68k: Bug fix and cleanup for framebuffer debug console Finn Thain
2025-03-27 22:39 ` [PATCH v3 1/3] m68k: Fix lost column on " Finn Thain
2025-07-06 10:27 ` Geert Uytterhoeven
2025-03-27 22:39 ` [PATCH v3 3/3] m68k: Remove unused "cursor home" code from " Finn Thain
2025-07-06 10:27 ` Geert Uytterhoeven
2025-03-27 22:39 ` Finn Thain [this message]
2025-07-06 10:27 ` [PATCH v3 2/3] m68k: Avoid pointless recursion in debug console rendering Geert Uytterhoeven
2025-06-11 15:11 ` [PATCH v3 0/3] m68k: Bug fix and cleanup for framebuffer debug console Stan Johnson
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