BD scroll — ZXNet «real.speccy»

From Ivan Pirog To All 10 October 2000

Greetings, All!

Who knows the principle of leafing in Born Dead?

Sincerely, Ivan.
Valtron/Complete Failure Hackers Group/Freedom
[ZX] [Alasm] [Beer] [Girls]

From Alexander Groholsky To All 11 October 2000

Hello Ivan!

October 10, 2000 (Tuesday) at 07:43:42
Ivan Pirog wrote to All on the topic "BD scroll":

IP> Who knows the principle of scrolling in Born Dead?

I can’t say for sure, because... I haven’t looked into the code, but looking at the indicators of the memory banks, you can see that something is being built, probably a sprite, and then it will scroll pixel by pixel and smoothly!

Well, that’s all, Ivan, for now.

Alexander Grokholsky was with you October 11, 2000
[I ZX] Spawn/Last Masters Group/X-Project Association Wednesday 12:31:43

... [Speed Garage] [House] [Rave] [Trance] [Electro] [Drum'n'Bass] [Jungle]

From George Valnin To All 12 October 2000

AG> I can’t say for sure, because... I haven’t looked into the code, but looking at
AG> indicators
AG> memory banks, you can see that something is being built, probably a sprite, and then
AG> it will scroll pixel-by-pixel and smoothly!

Yeahhh..., not a lot of text will fit in this way... 400 lines of text in 6
banks...

Sincerely, George aka -=GPV=-.

From Yuri Potapov To All 13 October 2000

Konichi wa, George-san!

Once Thu 12 Oct 2000 at 23:55:45 George and Alexander were arguing about BD scroll

GV> Yeah... not a lot of text can fit like that...
GV> 400 lines of text in 6
GV> banks...
More! Monster is a genius!

▒▒▓▓▓ ▄▀█▀▀▀ ▓▓▓▒▒░░░ Sincerely yours, Yuri /I \
▒▓▓▓ ▐▌▀█▀ ▓▓▓▓▓▓▒▒▒░░░░ Jerri / Alien Factory \ZX/

From Kirill Frolov To All 14 October 2000

Elementary. Where have you been, why haven’t you subscribed to code.zx? There all this
was discussed, although a very long time ago, I was still in spec. 24 full lines
cannot be output, so fewer lines are output and/or
the font uses not 8 lines, but only 7 or even less. Then
the text is not directly displayed on the screen, but a
program is first generated to display one page, and then immediately displayed. Scroll
is also not really there, everything is just re-translated from the desired
line. Here is a very approximate version of the output program:

ld sp, xxxx
ld hl, xxxx
push hl
ld hl, xxxx
push hl
....

This program takes up a lot of memory, probably 16 kilobytes or more
for just one page of text. Well, at one point in time in such a
representation
more than a page is not stored. The fonts are also pre-shifted by the required
number of bits.

From Alex Baskakov To All 14 October 2000

KF>
KF> Elementary. Where have you been, why haven’t you subscribed to code.zx? There all this
KF> was discussed, although a very long time ago, I was still on spec. 24 full lines
KF> cannot be output, so fewer lines are output and/or
KF> the font uses not 8 lines, but only 7 or even less. Then
KF> the text is not directly displayed on the screen, but a
KF> program is first generated to display one page, and then immediately displayed. Scroll
KF> is also not really there, everything is simply translated from the desired
KF> line again. Here is a very approximate version of the output program:
KF>
KF> ld sp, xxxx
KF> ld hl, xxxx
KF> push hl
KF> ld hl, xxxx
KF> push hl
KF> ....
And it’s not true. If it were so simple, everything would have been done long ago. In this way
only 22 lines fit into the interrupt. With 8x6 font. No music. And in BD there are 24
lines, 8x7, music and colors.

mp3: Avail - 03 - August
Pr. more, L.

From Alexander Groholsky To All 14 October 2000

GV> Yeah..., not a lot of text will fit this way... 400 lines of text in
GV> 6
GV> jars...

Okay! Let's take and look at the code, may the creators of BD forgive me, and we see that the text
is stored as follows, both the output and the data for output:

===== the beginning of a piece of text from BD =====

...
LD SP,(42648)
LD HL,112
PUSH HL
LD HL,30578
PUSH HL
LD HL,1029
PUSH HL
LD HL,28791
PUSH HL
LD HL,39
PUSH HL
LD HL,21591
PUSH HL
LD HL,10069
PUSH HL
LD HL,7
PUSH HL
LD HL,17749
PUSH HL
LD H,A
LD L,C
PUSH HL
LD L,39
PUSH HL
LD HL,10055
PUSH HL
LD HL,28786
PUSH HL
LD HL,29957
PUSH HL
LD HL,30567
PUSH HL
LD HL,9590
PUSH HL
...

===== end of a piece of text from BD =====

and this way the entire text is displayed!!!
Although I deviated from the topic of the subject, they generally asked about scrolling, and I was asking about output,
well, scrolling is apparently made by a cyclic buffer.
ps: Sorry about the decimal notation system, well, I just disassembled the STS
;)

Well, that’s all, George, for now.

Alexander Grokholsky was with you October 14, 2000
[I ZX] Spawn/Last Masters Group/X-Project Association Saturday 17:50:37

From Dmitry Lomov To All 15 October 2000

Hello, Alex!

Once, Sat Oct 14 2000 19:49, Alex Baskakov wrote to Kirill Frolov about [BD
scroll]:

KF>> pages, and then it is immediately displayed. There is actually no scrolling there either
KF>>, everything is just translated from the right line again. Here
KF>> is a very approximate version of the output program: ld sp,
KF>> xxxx ld hl, xxxx push hl
KF>> ld hl, xxxx push hl ....

AB> And it’s not true. If it were so simple, everything would have been done long ago.
AB> In this
AB> way, only 22 lines fit into the interrupt. With 8x6 font. Without
AB> music. And in BD there are 24 lines, 8x7, music and colors.

and how is it done there? ;)

All the best.
Dmitry.

... LD..X-TRADE... [ZX] [Quake]

From Yuri Potapov To All 16 October 2000

AB> for a long time. In this way
AB> only 22 lines fit into the interrupt. With 8x6 font.
AB> Without music. And in BD 24
AB> lines, 8x7, music and colors.

And all this works only
because the person who wrote it thought long before
and the principle is not called Mozgan Pusher for nothing

From George Valnin To All 16 October 2000

AB>> In this
AB>> way, only 22 lines fit into the interrupt. With 8x6 font.
AB>> Without music. And in BD there are 24 lines, 8x7, music and colors.
DL> and how is it done there? ;)

A person simply doesn’t know how to count bars. :)

From George Valnin To All 16 October 2000

Hello, Alex!

14 Oct 00 19:49, Alex Baskakov -> Kirill Frolov:

KF>> output program option: ld sp, xxxx
KF>> ld hl, xxxx push hl ld hl, xxxx
KF>> push hl ....
AB> And not true.

True.

AB> If it were so simple, everything would have been done long ago.

There is NO faster way!

From George Valnin To All 16 October 2000

Hello, Alexander!

14 Oct 00 17:02, Alexander Groholsky -> George Valnin:

AG> and this is how all the text is displayed!!!
AG> Although I deviated from the topic of the subject, they generally asked about scrolling, and
AG> I’m talking about
AG> output, but scrolling is apparently made by a cyclic buffer. ps: Sorry about
AG> the decimal notation system, well, STS just disassembled
AG> ;)

In general, this method has been known for a very long time. I made a reader like this in 1996
(although the newspaper it was intended for was destroyed).

From George Valnin To All 16 October 2000

YP> More! Monster is a genius!

Yeah... I have such a reader, but with a cool print (the fastest :) ) back in 1996
I did...
And to lay out a multi-kilobyte output, like in BD, you don't need a lot of intelligence...

From Evgeny Goljakov To All 18 October 2000

...
GV> In general, this method has been known for a very long time. In 1996
GV> I made a reader like this (although the newspaper for which it
GV> was intended died).

Which one? isn't it 'FUCK'? Z;))

Thank you for your attention.