vdp_guide: Test program for r#18 interaction with copy commands and the display.

This test program cycles through four different stages:

1. Full screen copy while r#18 horizontal offset decrements, sprites enabled.
2. Full screen copy while r#18 horizontal offset increments, sprites enabled.
3. Full screen copy while r#18 horizontal offset decrements, sprites disabled.
4. Full screen copy while r#18 horizontal offset increments, sprites disabled.
2 files changed, 4 insertions(+), 0 deletions(-)

M articles/vdp_guide.php
A => downloads/articles/vdpreg18test.zip
M articles/vdp_guide.php +4 -0
@@ 30,6 30,8 @@ occurs regardless of whether you have th
 is the case, you should wait with setting r#18 until the VDP’s CE bit indicates
 the current command is finished.</p>
 
+<p>See <a href="/downloads/articles/vdpreg18test.zip">this test program</a>.</p>
+
 
 <h2 id="r18disp">Q: What about screensplits with the help of r#18?</h2>
 

          
@@ 38,6 40,8 @@ cycle, if you move the screen horizontal
 can be blanked. This only happens when the sprites are disabled. So if you’re
 creating a screensplit with r#18, watch out for this.</p>
 
+<p>See <a href="/downloads/articles/vdpreg18test.zip">this test program</a>.</p>
+
 
 <h2 id="vdpstrange">Q: VDP does lots of random strange things, how come?</h2>
 

          
A => downloads/articles/vdpreg18test.zip +0 -0