Inferno #10 30 апреля 2007

Железо

ZX Clones - multiplatform on the ZX Spectrum. Computers SAM Coupe and MSX.

      Multiplatform

   Because now each produced ZX
Spectrum has a mode of "Color to the point,"
then we can look towards a
кроссплатформенности.Рассмотрим to start
Computers MSX (specifically MSX2 - with video
 controller V9938 and above) and the SAM Coupe.

   Both of them have Z80 as a central
Nogo processor, some sort of beeper and
which is similar to AY (in the case of SAM - very
distant similarity called SAA 1099,
However, the MSX - a very real AY, in
 if it is not built into the chipset).

   And MSX2, and SAM are of interest to us
raster mode is 256x192 in 16 colors (with at
tunable palette). Hardware sprites
we are not at this stage interesuyut.Razgovor
the assembly of one and the same program under all
These machines.

                        ,

                SAM Coupe

                    ,

   Briefly, SAM Coupe - this is the wrong
Spectrum. The machine is compatible with ZX Spectrum
48k, but no more. ,

   Authors SAM Coupe decided that the switch
memory in the windows of 16k - excessive luxury.
Therefore, you can click only once 32k
(2 boxes: # 0000 .. # 7fff and # 8000 .. # ffff), but
indicate projected back a chunk of memory
can be up to 16k. Such a decision in
all used local BASIC. He ate
sum of # 8000 - # bfff, and when crossing
# C000, switches the memory of # 8000 # ffff, and again begins 
to move with the # 8000. Thus organized virtual PA

crease (almost 256k), which can take
nemerenoe BASIC program.

   SAA 1099 chip does not have the envelope, but
has several voices sound to 6 channel
fishing. Argue that the problem of converting
sound AY at SAA 1099 resolved, but I have not seen
Affairs of the converter and all doubt.

   Machine is distributed fairly weak, and
people who can be consulted
on technical issues can be counted
by paltsam.V primarily Simon Owen
- Author of the emulator Sim Coupe. However, it is necessary
sary to develop a set of utilities, including krossrazrabotki 
there. 


                   MSX


   If SAM - this is the wrong Spectrum, the
MSX - Spectrum is very wrong:)
Compatibility does not expect any.

   For example, the pulse interrupt (INT) there
by itself does not need to shoot snimaetsya.Ego
manually (refer to the device port
its called) in the interrupt handler,
otherwise, after EI handler will be called
again. Apparently, this was the most simple method
sobom solve the problem of interrupt handling
from many sources, that none of them
not lost.

   In the 7 th register AY can not be installed
Both channels of I / O output - MSX model
Jette sgoret.Oba to enter - you can (as the case
em system itself). Generally, for proper
of the joystick output should operate
only port B. Said protection is envisaged
ered in the existing music players and
effects.

   The scene on the MSX very big and active,
PC is widely distributed (including the number
le in the former Soviet Union) and is still
long (One-chip MSX). Documentation for any
piece of metal and software tricks can be on
yti, poked in the Internet, so I will not
delve into further technical details
Do. Iron on the MSX too much, and even
half of the program does not need to know to write a game.

   The principal challenges in programming
 mation of MSX on are the following.

  1. RAM, the CPU is severely limited. On
different models, different amounts of RAM, but
should expect to 64k, and # d400
and more busy. VideoOZU (VRAM)
 on MSX2 usually 128k.

  2. The preferred frequency of personnel
sweep is 60 Hz. Of course, 50 Hz
suitable for Europe, but to enhance audit
trajectory is better to choose 60 Hz (European ones
hnika 60 Hz, too, suffers). Good sources
Nick interrupts with a frequency of 50 Hz in this
If not, why music should AY
transfer to another temp.Mne traps one
log (Disk), which provides you
 Boron 50 Hz / 60 Hz. However, this is not typical.

  3. The location of the letters on the keyboard matrix
tours vary depending on the model MSX
(More precisely, from a country which is oriented
this model). Software to determine the distribution
masonry work can not be, except by software
determine the machine model - and this is made difficult
tively with the abundance of existing
models. Therefore, it is better not to interview letters
in the program, do managers and
function keys.

   The fact that you can use the additional
Indeed - a popular sound device
FM PAC (MSX Music), which has nine melodious
channels, 5 or 6 channels of melodic punch
GOVERNMENTAL. One instrument can be overridden.
Not be ruled out that the music under TurboSound FM
can be roughly converted into FM PAC, selecting
other tools.


                  *



   As you can see by Source
Ball Quest Gold Release, from these initial
Cove can be compiled quite serviceability
of viable version under MSX2 (a minimum
Machine: 64k RAM + 64k VRAM). Necessary
to build the tools are there. Why not
MSX version of itself is laid out? Because it
sent to the MSX2 game development chal
lenge, the organizer is not strong Snout
 but in a hurry to open the contest site.

    We are waiting, sir.

   From sources Ball Quest can without difficulty
so do even some game on the same
engine, and it will work on ATM Turbo
2 / 2 +, Pentagon1024SL v2.x and MSX2. For MSX2
need to collect used sprites in general
bmp, who during the game will be in the
video memory (VRAM).

Alone Coder