Some one time ago, told me that on msx2 modes the early clock bit in the SAT is considered.
This is surprising me because until now, for me the early clock bit is on scanline base to in the old msx1 like SAT.
(Where the color of the entire sprite is defined).


If this is true, setting the EC bit in sat should move 32 pixels left the entire sprite, not the nth scanline.

This sound strange to me, anyone could verify on the real machine?

There's indeed a bit that causes (a) sprite(s) to move some pix to the left, dunno if it's the bit you talk a'boot.
wich reg r ya talkin'boot? (excuse my Canadian, to much southpark this weekend)

OK, I Need some clarifications:

on msx2 the ec bit is on attribute table, so you can shift left sprite pixels on a line basis.
I do not remember exactly who and where but i've heard about the fact that the msx2 vdp also consider this bit on the MSX1 like SAT table.
This is what i do not know. so giving the sat


Y
X
Pattern
color & ec bit

on msx1 setting the bit shift effectively the entire sprite.

on msx2 this is done on a sprite row AFAIK, but someone told me that this bit is also readed from the old sat table... instead of the sprite attr table


Is This true?

if you are asking if is possible to shift one line 32pixels to de left... it is not .

now about both EC bits being taked in account.....

I thinks maybe... I never needed that bit outside of BASIC.

but if both are active, they will be proceses with a OR logic before to draw a line lefted 16pixels.

PingPong: in MSX2 there's a sprite colour table, which contains 16 bytes for each sprite. It also has 16 EC bits and all have to be set if you wanted to have your sprite shifted 32px to the left. FYI, the sprite colour table location is &SPRITE_ATTR) - 512.

When a (16x16 ) sprite has an x coordinate of 248,
only HALF of the sprite will be in screen.
so the rightborder makes the sprite to be displayed partially.

This does not happen on the left side.
If you sprite has x coordinate x=0 then the sprite will be completely in play.
if then the sprite moves left (x=-1) then the sprite will disseapear from the left side of the screen, (and will appear right again)

In order to have the sprite move smoothly out of play ALSO on the left side,
the EC bit was created.

This has nothing to do with the SAT,
the EC bit can be given to a sprite in the color table.

when, in the color table, the EC bit is on, this line of the sprite will be shifted 32bits left.
So Yes, you can shift also PART of the sprite 32 pixels left.

http://bifi.msxnet.org/msxnet/tech/tms9918a.txt

Quote:

If bit 7 of the ``colour sprite'' is set (Early Clock -- EC), the sprite is moved 32 pixels to the left; in this way it's possible to partially display the sprite at the left side.

wait ... 32pixels to the left? was't 16pixels? remerber that the sprite is 16x16.??? ahh, maybe thinking in the MAG mode the EC works shifting 32pixels

note: 32pix <> 32bits... as I readed

ok,


He asks about:

what happens if in a msx2 screen mode....

we try to use the EC bit at the sprite's attribute table instead of setting the 16 individuals ECs bits at colour table?. ¿It has any effect?...

Quote:

ok, He asks about: what happens if in a msx2 screen mode.... we try to use the EC bit at the sprite's attribute table instead of setting the 16 individuals ECs bits at colour table?. ¿It has any effect?...

exactly! that's the question

I know that for screen 5:
the 4th byte of the SAT has no function at all.
So that probably also goes for screen4.

flyguille: 16 bytes it is, alright. I was thinking of SCREEN5

again bytes <> pixels...

Quote:

wait ... 32pixels to the left? was't 16pixels? remerber that the sprite is 16x16.??? ahh, maybe thinking in the MAG mode the EC works shifting 32pixels note: 32pix <> 32bits... as I readed

All a bit confusing !! ^_^
it is 32 pixels to the left, NOT 16

Btw, how does the 4th bit of the SAT work for msx1, anyway ?

Quote:

how does the 4th bit of the SAT work for msx1

Indeed it's confusing!. It's the 4th byte of the SAT on MSX2 machines!

Today I'll test it on a real MSX2, I'm getting curious...

32pixels ? hmmm in screen 5 and 8 surelly

in 6 and 7 must be 64pixels......

yes I tought yesterday 32pixels because in MAGnified mode it needs 32pixels left, and I imagine that the v99xx hasn't two Early clock, one at 16 and other at 32 that's by sure.