[OpenBIOS] [PATCH 14/16] display.fs: optimise scrolling by copying/deleting multiple scanlines at once.

[Mark Cave-Ayland]

Change fb8-copy-line and fb8-clear-line so that they can operate on multiple
lines at once, renaming to fb8-copy-lines and fb8-clear-lines respectively.
Integrate these new functions into fb8-delete-lines so that they are used
when scrolling the display.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
---
 openbios-devel/forth/device/display.fs |   41 +++++++++++++++-----------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/openbios-devel/forth/device/display.fs b/openbios-devel/forth/device/display.fs
index 75aa632..a0a182c 100644
--- a/openbios-devel/forth/device/display.fs
+++ b/openbios-devel/forth/device/display.fs
@@ -174,17 +174,20 @@ defer fb8-invertrect
   window-left +
 ;
   
-: fb8-copy-line ( from to -- )
-  fb8-line2addr swap 
-  fb8-line2addr swap 
-  #columns char-width * depth-bytes * move
+: fb8-copy-lines ( count from to -- )
+  fb8-line2addr swap
+  fb8-line2addr swap
+  #columns char-width * depth-bytes *
+  3 pick * move drop
 ;
 
-: fb8-clear-line ( line -- )
-  fb8-line2addr 
-  #columns char-width * depth-bytes *
-  background-color fill
-\ 0 fill
+: fb8-clear-lines ( count line -- )
+  background-color 0 
+  2 pick window-top +
+  #columns char-width *
+  5 pick
+  fb8-fillrect
+  2drop
 ;
   
 : fb8-draw-character ( char -- )
@@ -268,20 +271,14 @@ defer fb8-invertrect
 : fb8-delete-lines ( n -- )
   \ numcopy = ( #lines - ( line# + n )) * char-height
   #lines over line# + - char-height *
-
-  ( numcopy ) 0 ?do
-    dup line# + char-height * i +
-    line# char-height * i +
-    fb8-copy-line
-  loop
-
-  #lines over - char-height *
-  over char-height *
-  0 ?do
-    dup i + fb8-clear-line
-  loop
+  over line# + char-height *
+  line# char-height *
+  fb8-copy-lines
   
-  2drop
+  #lines over - char-height *
+  dup #lines char-height * swap - swap
+  fb8-clear-lines
+  drop  
 ;
 
 
-- 
1.7.10.4