Hi, all. We all know that we can out data more faster in vblank to vdp than in active area.
My guess is that on msx2 also the cmd engine is more faster when a command is issued on vblank and keep running in vblank period.

Anyone can confirm?

That is correct

I confirm

see also this
http://map.tni.nl/articles/vdp_commands_speed.php

Quote:

Hi, all. We all know that we can out data more faster in vblank to vdp than in active area. My guess is that on msx2 also the cmd engine is more faster when a command is issued on vblank and keep running in vblank period. Anyone can confirm?

There's a nice article on MAP which describes the approximate command speeds under different situations. Make sure you have a look at it, it gives an idea of what you can expect of the VDPs command engine.

hehe, too slow... ^_^ (In my defense, he used edit! )

OK, thanks, i know this. The article test several conditions: sprites on/off 192/212, blank screen.
BUT what i asked is: not blank screen (that is covered in the article) BUT the period that is between the line 213 and just before the line 0 of the next frame. I guess this is the same as blanking the screen but i'm not so sure. Maybe some strange logic in VDP handle this as a normal screen area, so no benefits.

IIRC the MSX1 VDP works the same with disabled screen and during the VBlank. I also guess that the 9938 must be like the 9918, no work on screen, more speed for operations.