Commit 0da64584 authored Mar 28, 2025 by Finn Thain Committed by Geert Uytterhoeven Jul 06, 2025

m68k: Avoid pointless recursion in debug console rendering

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>
Tested-by: Stan Johnson <userm57@yahoo.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/a6104f41918bed4fd17f92c45df94ac7a5d30e40.1743115195.git.fthain@linux-m68k.org

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

parent 210a1ce8

arch/m68k/kernel/head.S

+4 −7

Original line number	Diff line number	Diff line
		@@ -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