listening to you? - Valeron to speculate about "what is missing Spectrum?"
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Listen to you? / / / Valeron
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What we have not enough.
Hi, people! Again I waste your time by their ravings. But
want to get worn out, and not with anyone.
And the reason for idle talk is: the video mode of our
favorite Speck. At the dawn of the dawn, and someone may be in
the midst, platform in our postsovke loved to scratch the
language on the topic how many colors and many points in a row
I would like to have on Spectrum. Seriously reasoned from the
pages of the then popular electronic journals as desirable
colors and tables Drive - how much memory it eats. Cool it
appeared almost not all 128 kilobytes of the video. I was
still quite green, was read and admired his mouth agape: To
what future awaits!
However, the added years of cynicism and skepticism, I
realized how difficult standard screen for one int transfer,
no different tricks with stekom not do, and even then not on
all models a number of passes, some ungodly slow down. Of
course Turbo mode is good, but in turbo mode to get double
acceleration of the RAM is almost impossible (if I am mistaken
- do not hurt!), but the essence of something else: how much
will be built this screen memory? Even in turbo mode? Suggests
itself: conclusion: the screen should not take up much memory,
but this too Of course you can sporit.No matter how much we do
not want to see colors on the screen, we should remember about
the performance processor and so the video area should not be
large. If can still be reconciled with the fact that the
screen is being transferred for 5-10 Mounting, the
construction of such a screen in the memory will be hideously
long. I think you should not go beyond the double size, so
6912 + 6912 = 13824. Yes, of course, be and take a whole page,
16384 bytes, but if you have enough patience to read till the
end of this opus, you'll understand why is 13,824.
Make an extended color mode will not be easy, but this
The situation as it is also not satisfied with one color on
the familiarity and one background greatly complicate the
creation of color graphics, especially not full screen. Well
sprite 2 to 2 familiarity (that would be maintain an overview
of as much as possible the site map is selected the smallest
size of a sprite) skrolirovat pixel by pixel and save Color?
Need at least one more bitplan. This is not so burdensome for
the CPU and is completely acceptable from an aesthetic point
of view: while maintaining the system color / familiarity,
which is very convenient in terms of compactness of the video
field, is obtained for 2 color and 2 background. The
background is the background and will have to do the same, but
color - a real goldmine for gfx-maker.
Do not claim to originality of ideas, because the whole
universe evolves in a spiral, and certainly someone came into
his head something like that, but we should say it out loud.
So, the idea itself was formed when we had to
enjoy shaking saver when each interrupt
switches 5 and 7 pages of memory in the video field. Jitter
of course on your nerves, but the picture obtained cute.
RAGE such tricks are often used. If you remove the jitter -
that you additional bitplan. What comes to mind on this
about it? You can make as General Sound with a separate
processor and his memory, but you need to do a little blood,
the cost of General Sound played, in my opinion, rokovyyu role
in rasprostronenii this rulnogo devaysa. Our device must
be cheap, accessible to all, otherwise little chance of getting
rasprostronenie, and accordingly it will not support
programmers, and it will remain useless bloat.
The second way - to intervene in the work of the video
processor and to form a screen with two pages. In my not the
best way because in the different components of video
processor is implemented on way. But judging from the Baltic
Sea, it turns out very tempting to try to switch the memory
page from the fifth to seventh in a time when the video
processor selects bytes screen. There should clarify what I
mean. In the Baltic processor receives a command waiting on
line when the WAIT display area becomes video processor. On
the memory bus appears low byte of the address attributes in
the next step of this B is taken into the internal register
register RU'shek and on the bus fed the high byte of
attributes. In the next step of this bytes received RU'shkami,
and then in the next cycle of RU'shek read data byte in a
register that is implemented on a separate chip. If not now
awaiting arrival of the next clock pulse to change one bit
address corresponding to the number of page to signal CAS to
record the resulting new high byte of Ru'shki and then read
from RU'shek bytes of data in another register, which will
implement additional soldered another chip IR27, then we
obtain two separate attribute byte corresponding to the same
position of the screen. Further, in the same way we proceed
with the byte data screen which is chosen in subsequent
cycles. So we get two bytes attributes and two bytes of screen
data. Now we only need bring them to release the video. To do
this, you can simply Duplicate the appropriate chip in the
Baltic Sea is a KP15 and two KP12, and a total of three
registers IR27 obtained only six cases. The trouble is that
I'm not sure that such an approach work, I have no job
descriptions for RU5 and I do not know where How often you can
access them.
The third way - not the most elegant, but it seems to me
the most acceptable. Need to preserve the image of the screen
say the fifth page, and mix it with the image of the seventh
page in memory.
How it will look.
Video processor every fiftieth of a second begins
sample screen of the video area. For once chosen a
bytes. This byte is written into an intermediate register
implemented on a separate mikruhe. Further into the different
components of differently, some take it multiplexers, in
others - shift registers, it is not so important - most
important of which This register can take the byte and treat as
want.
So, the idea that would save the byte in a separate
mikruhe memory. Take mikruhu dynamic memory, such as
RU17 to 8 kilobytes. Screen attributes requires 6,912 bytes,
quite fit into our RUshke. This will be the screen buffer.
Now when selecting a video processor bytes of screen memory
should be considered in our RUshki bytes and store in a
separate register, and at this place in RUshku record only
that the seized video processor bytes. Now we have two display
bytes can impose a bit of both at each other
respective colors inc and paper.
Until switch pages 5 and 7 in the video field
computer, of course, B will be the same, but if the same
start now everyone int switch screens from fifth to seventh
and back, then we can get nedrozhaschee (!) image.
Well, let's say in a normal spektume display byte is taken
bit at a time and in the light-colored dot on the screen is
formed image is then fed to the video output. We now need to
replicate the process and parallel process in exactly the same
read the second byte, and the stage of formation of the screen
picture mix bits of logic "OR". Can be different:
to form a point image of the first byte of its own, from the
second - Their own, and then, when it will be supplied to the
video output - mixed signals. Since the video output are
generally divider resistors, we can offer such a scheme in
which changes koofitsient division and then you can get a
double brightness for a single color or shades of the new
mixing for example purple and yellow for example. You can even
separate register set koofitsienty division for each color
and thereby set the palette image. You can make two
separate register and set the palette for each of the two
bitplanov. How do you like this: 16 colors from a palette of
256? And given poluyarkosti Bright - twice.
Now the bitter. This design does not allow output
animation at 50 frames per second, namely the old sprite
will be superimposed on the new and the screen will stretch
the tail for a sprite. Although it is possible to offer the
option of constructing sprite, when we say the body appears in
the fifth page, and feet in the seventh. Then, changing
alternately in the fifth then the seventh page of sites you
can get normalnyuyu sprite animation. In this regard, this
option is less convenient than the other way which I described
above.
All the above is a crude idea, and not backed
any experiments, any attempt to implement this on
practice has not yet been undertaken, unfortunately, all that
I write that would share with the people concerned with their
ideas.
And finally, who it can create in the gland. Should you
upset, but I can not. Maybe someday I will achieve this
level, but so far I've only dissect and Bytes
Baltic Sea, and the map needs a universal, for any company.
And in alone to develop such a device itself, you will agree,
is difficult. In any case, I will be glad if someone
zaiteresuetsya this idea.
16.09.1999
FOX> So, Valeron gave his point of view. You can not disagree
that the Spectrum screen leaves much to be desired. However,
no one has yet solved this problem. Why? Maybe it is not
really? May be needed to finally admit that Spektrumeto
Spectrum and not try to make him God knows what? Maybe
be still needed to look for? After all, who are looking for,
he finds! Like to hear your thoughts! E-mail us!
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listening to you? - Valeron to speculate about "what is missing Spectrum?"
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