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(C) MELTED SNOW, 1998
SUPERSPECTRUM processor-based Z80000.
Development prospects.
In recent years, increasingly heard talk about how
that Spectrum needed a new iron, which is to somehow extend it
life and bring it to a better class of computers.
The remaining firms proivoditeli Spectrum, trying different
ways to attract buyers, coming up with new and
New prichindaly not compatible with other versions of the
laptop, and thereby making more confusion in dataprojektor
market. Y user (potential customer) develops
a kind of inferiority complex, namely, the fear to buy
expensive computer, which may well not digest available
Spectrum soft. Output from the vicious circle of just one -
negotiate the leading firms on the main producers hard'a
Spectrum of concepts and to introduce a mandatory standard on
manufactured product (eg computer KAY 256 firms in NEMO
fuller compatible with Scorpion 256, that is, can if I want).
What is offered today as a model
future-is only a smile. For example, I quote: "The new
Spectrum-compatible computer is - the processor Z80H, RAM
512-1MB hard drive, covox ... "(funny to say, but should Z80H
was standing on the computer, "Locke" as much in 1987 and now
satisfied unless AON'y). Or, for example, offer now
Computer "Sprinter" - is that the hybrid IBM XT with Spectrum
(and compatibility is not complete and the PC obsolete). Firm
in NEMO Recently, serious (?) took up this issue and suggested
create a new kopyutera (TRANSFORMER), rather than spoil the old
Speccy. TR-R according to her need to establish a processor
Z186. But first, he does not give full compatibility with the
Z80, and Second is relatively expensive. I want to offer you my
Future version of the Spectrum with a processor Z80000. But for
early to tell what kind of processor and how is it better than
others. AND as follows:
32-bit CPU Z80000 is compatible with 16-bit microprocessors
family Z8000 and 8-bit family of Z80. Therefore, in part
internal capacity, he is the most powerful 32-bit
processor, since it has internal cache memory, and
memory management unit, and its frequency synchronization
is 25MHz. In CKD, there are 6-stage command pipeline and
its performance matches 4-5 million op / sec. In CP
stored command block transfer and search strings. In the device
There are 9 addressing modes, and in the calculation of
addresses can participate ragistr base, the index register and
the register bias. Defined in the command memory address may be
interpreted one of three ways depending on the state of the two
bit in flags and control:
a) a compact representation - 16 bit (provides addressability
64 KB);
b) Segment performance - 32 bit (15-bit segment
16-bit offset for the first 2 GB or 7-bit 24-bit
shift for the next 2 GB;
c) a linear representation - 32 bits (adressatsiya 4 GB).
When Moreover, the address representation of address
computations affect only on the field offset.
Address specified in the command is called a logical
address, and memory management unit converts it to
physical address. This conversion follows
as follows:
1) involving the internal buffer of the transformation, where
stored tag addresses and information about the last 16 pages to
which produced treatment similar way cache commands /
data;
2) if the buffer conversion fuiktsiruet not match tag
then the CPU accesses the conversion tables in memory using
for this is one of four registers descriptor table, and then
perdaet necessary information in this element of the buffer
transformation which for the longest time there was no
treatment. In addition, the memory management unit provides the
means protection, for example, the treatment only for the
resolution of reading and writing.
The internal cache memory consists of 16 items to 16 bytes
each. It records information about the 16 memory cells, to
which is the last appeal. When the cache
obtained by slip, while fetching instructions from the adjacent
memory cells passed a package that optimizes the process of
reading out memory.
Among other things, the microprocessor Z80000, like his
16-bit predecessors, is working with processors expand
EPU (ie, simply speaking with a co-processor). Coprocessor
float Z8070 operates with 16 and 32-bit magnetic field (in
result you can get a machine that for 3D-games is quite
overtake "naked" Amiga and piblizitsya to the notorious PC486).
K Z80000 can be connected and other support circuitry,
for example, the controller DMA Z8016 (for connecting
components in large configurations firm Zilog uses its standard
called Z-bus).
Based on the Z80000 can create and SUPERSPECTRUM with the
following characteristics and hardware:
1) 25 MHz processor;
2) math coprocessor;
3) the amount of memory (RAM) of 4 MB or higher (SIMM,
extension through the slot);
4) Video Controller allows you to display on screen 80
columns by 25 rows, and a graphic image with a resolution
640x480 pixels (such resolution is chosen for several reasons:
First, it complies with the standard VGA, ie will not
problems with converting graphics from PC; secondly, domestic
video monitors and TV did not provide a much clearer picture;
and thirdly, at a higher resolution the computer will not
have time to print the whole screen for one interrupt);
5) the number of colors issued by the display adapter 256 of
the palette 65535 colors, video memory 512 KB (steeper
characteristics lead to operate at a higher cost
computer is another option - to place a video controller
a separate slot for a change in the future with more powerful);
6) hardware scroller screen (for a smooth
scrolling the screen);
7) 16-bit sound card with its own memory, no less
512 KB for the digital effects (everything else should be
in the computer's RAM, not to impose restrictions on the size
music; board should be inserted into a 16-bit slot in
which can be inserted and an 8-bit GENERAL SOUND);
8) Controller IBM-compatible keyboard and mouse active,
serial and parallel ports;
9) drive controller (I advise to install a ready-made
product drive 3,5''cheaper and more reliable);
10) the existence of an IDE interface to connect both
vozmozhmostyu Hard disk and CD-ROM (the possibility it may
appear);
11) housing for a computer is desirable MiniTower (it always
all the climbs and inexpensive);
12) operating system for the new Spectrum should be
multi-tasking (something like AmigaOS with built-in emulation
Mode Spectrum 128 and TR-DOS, as well as support for the format
MS-DOS);
13) the price of the main board can not exceed $ 100
(otherwise If the total price of the computer will not afford
the potential customers).
Since one firm is not podsilu in a short time to realize
such a project, it must be the leading producers
Spekrumovskogo iron unite to develop a common vision
new computer, and only compete in terms of technological
implementation of these characteristics and the cost of finished
product.
