The inner loop deals with a contiguous region. It could easily be replaced
by faster board specific functions like hv-logical-memop in board-qemu.
Since hv-logical-memop does not return an address, let's have the enclosing
loop compute the next line address by itself and drop the confusing
"char-width screen-depth * -" address adjustment.

Signed-off-by: Greg Kurz <redacted>
---
 slof/fs/fbuffer.fs |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/slof/fs/fbuffer.fs b/slof/fs/fbuffer.fs
index 756f05a..faae6a9 100644
--- a/slof/fs/fbuffer.fs
+++ b/slof/fs/fbuffer.fs

@@ -99,8 +99,8 @@ CREATE bitmap-buffer 400 4 * allot
 : fb8-toggle-cursor ( -- )
 	line# fb8-line2addr column# fb8-columns2bytes +
 	char-height 0 ?DO
-		char-width screen-depth * 0 ?DO dup dup rb@ -1 xor swap rb! 1+ LOOP
-		screen-width screen-depth * + char-width screen-depth * -
+		dup char-width screen-depth * 0 ?DO dup dup rb@ -1 xor swap rb! 1+ LOOP drop
+		screen-width screen-depth * +
 	LOOP drop
 ;