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-rw-r--r--newtitle.s12
1 files changed, 12 insertions, 0 deletions
diff --git a/newtitle.s b/newtitle.s
index d62a40a..ae54481 100644
--- a/newtitle.s
+++ b/newtitle.s
@@ -28,6 +28,9 @@ start:
lda #0
sta SDMCTL
+ ; wait for the next frame, to avoid graphics glitching
+ jsr wait1jiffy
+
; setup our display list
lda SDLSTL
sta FR0
@@ -64,12 +67,21 @@ wait4key:
lda FR0+1
sta SDLSTH
+ jsr wait1jiffy
+
; switch to normal playfield, enable screen
lda #$22
sta SDMCTL
rts ; return to DOS
+wait1jiffy:
+ lda RTCLOK+2
+wait:
+ cmp RTCLOK+2
+ beq wait
+ rts
+
; display list here
dlist:
.byte $70 ; 24 scanlines of blanks