(C) Andrew Gura (EAGLE SOFT),
Kurgan.
One article I read REVIEW proposal wording in
which was proposed to create
a code for demomeykerov. I think it needs a code of programmer
at all and I think that my code will be an example to all
programmers and adopted as a basis.
Switching pages of RAM
Switch the page better
on port # 7FFD, rather than half # FD. This way you can avoid
many problems of compatibility of programs with other
computers. Take a notorious example INSULT MEGADEMO. This
program comes on PROFI, PENTANGON 128, but does not want to
work on SCORPION'e, and this angered many SPECCYUSER'ov (I
think the owners SCORPION'ov I understand).
PORT # 7FFD
Z Y X X X
X-RAM, the page number from 0 to
7, is connected with the address # C000;
Y-switching of the screen, Y = 0 -
# 4000, Y = 1 - # C000 (page);
Z-switching ROMs, Z = 0 -
ZX128, Z = 1 - ZX48;
Turn to port to switch pages easier to read
as follows:
140.
LD BC, # 7FFD
LD A, N +16; N-number of the page
OUT (C), A
2
At the time of changing the contents
port interrupts must forbid.
MANAGEMENT
KEMPSTON need to poll for
Port # 1F, rather than # DF, as
done on the ZX-NEXT. But on the
Port # DF (for those who do not know) is interrogated FULER
joystick.
PORT # 1F
F U D L R
F-FIRE-fire;
U-UP-up;
D-DOWN-down;
L-LEFT-left;
R-RIGHT-right.
Appeal to the port is
by mnemonic IN.
SINCLAIR 1 or 1 INTERFACE
here has the following keys:
1-LEFT; two-RIGHT; three-DOWN; 4-UP;
5-FIRE.
SINCLAIR INTERFACE 2 or 2:
6-LEFT; 7-RIGHT; 8-DOWN; 9-UP;
0-FIRE.
CURSOR: 5 + CS-LEFT; 6 + CS-DOWN;
7 + CS-UP; 8 + CS-RIGHT, and CS
are not obligatory, and its absence, even comfortable, but not
in all cases.
KEYBOARD: here it is better to stick sleduyushego standard:
O-LEFT; P-RIGHT; Q-UP; A-DOWN;
M-FIRE. Poll is on port # FE.
PORT # FE
Y X X X X X
The survey produced the following
as follows:
142.
LD A, N; N-number poluryada
IN A, (# FE)
2
POLURYADY
March 1 ... 5 6 ... 0 4
2 Q. .. T Y. .. P 5
1 A. .. G H. .. ENT 6
0 CS ... V B. .. SPC 7
0 - # FE
1 - # FD
2 - # FB
3 - # F7
4 - # EF
5 - # DF
6 - # BF
7 - # 7F
Poluryada port address can be calculated by the formula
255-2 №, where n - number poluryada.
Booting from CD
When you boot from a disk is strictly forbidden to contact
non-standard entry points TRDOS and use the method of
programming the SH, as all leads to an inoperable programs at
boot from the HDD, though it looks very impressive.
Again, take for example INSULT
MEGADEMO: I say with confidence that this program will not boot
from the hard drive.
You also can not bind to a specific program loaders
version of TR-DOS - it also leads to
incompatibility and dissatisfaction.
One would like to take your computer with
the old version of TR-DOS and throw it out the window. Perhaps
so did the fans of racing,
when they tried to get LOTUS
version of the Laptev, because they have version 5.03, but the
game is only on the 5.04.
When loading is undesirable
that a ship on the disk (so
no longer notice the owner
PC).
TIMING AND INTERRUPT
In all the programs when you use the interrupt
IM2 need to create the address table, consisting of 257
identical bytes (where do these bytes, I think, you know). Why?
- You ask, "It's waste of memory! ". An
No! - I can tell. It is believed that
with the data bus comes # FF, but
all Western programmers use a table.
Undesirable to send a vector
interrupt number, which contribute to the Treatment of address
to Rom, namely the number of 0-63, although
screen and the area of system variables is not worth touching.
All effects on the screen is better
synchronized with respect to
screen. For example, again take INSULT. In the first part
scrolling when the TURBOrezhime twitches. In the second part,
everything happens so fast that it does not have time to read
running line, and the music plays faster.
"PORT attribute
Never use your
programs port attributes # FF,
since it is an imaginary port. For
example, take the game TOP GUN.
OTHER GOODIES
The games definitely need to pause for a certain key is
pressed and shipping situation at any time of the game, each
situation must have its specific name.
Who has the additions to my code, write to the editor ZX
REVIEW.
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