vdp2: fix scroll_up

diff --git a/Kernel/dev/vdp2.s b/Kernel/dev/vdp2.s
index 60e6868..a09cddd 100644 (file)
--- a/Kernel/dev/vdp2.s
+++ b/Kernel/dev/vdp2.s
@@ -173,7 +173,6 @@ upline:
            ret
 
 _scroll_up:
-           ret
            ld b, #23
            ld de, #80          ; start of second line
 downline:   push bc
@@ -190,6 +189,7 @@ downline:   push bc
            add hl, de
            out (c), l
            out (c), h
+           dec c
            ld hl, #scrollbuf
            ld b, #80
            otir