On Mon, 17 Apr 2000 21:02:37 +0200, Duddu wrote:
>As you surely knows there is already a Brazilian Board made in such a way,
>but it is not cheap ! Moreover there was a project to build a new system
>(Phoenix Project), but it seems dead :-(
>The problem is
> some people wants to port MSX towards PC
> other people wants to make a new MSX that is a real MSX, not a PC clone.
>The only hw developer of Phoenix ML was Padial, not enough to decide the
>guidelines of a new MSX, the effort is too great !
From Brazil (Ademir Carchano) you can expect some new MSX (only MSX
compatible. Nothing about VGA, PCI boards compatible, etc... Please,
DO NOT ASK, because the idea is create the "Ultimate MSX" and do
it work as faster as possible, without breaking the standard)
in some months. It'll be fast, faster than TurboR, and it will use video
access through ADVRAM (Direct Access to VRAM by Z80/Z180). This could
make the MSX video about 5-7 times faster, once you will be able to
write on VRAM using LDIR/LDI, even when VDP commands are being
processed. For those that wants to see how it'll work, Ricardo Bittencourt
is preparing a new BrMSX version with -ADVRAM option.
Plus, the new MSX hardware will work with Z180 at 33Mhz, and *maybe*
will have some "patchs" to accept R800 and Z80 "secret" opcodes (once
Z180 have not them). Why Z180 and not Z380? Because Z180 is faster as
Z80 than Z380 in Z80 compatibility mode. Z180 at 33Mhz has a 3 cycles
per instruction against 4 of Z80 (actually five, on MSX hardware). This
makes Z180 at 33Mhz about 11/.714 ~ 15.4 times faster than normal 3.57Mhz
Z80. Z380 at 18Mhz (the faster it can be) has a 2 cycles per instruction.
It will give us about 9/.714 ~ 12.6 times faster than normal 3.57Mhz Z80.
This makes Z180 at 33Mhz something like 22% faster than Z380 at 18Mhz
(again, we are talking of Z180 working as Z80 and Z380 working as Z80).
Also, R800 has a 1 cycle per instruction (once it's RISC), but works
at 7Mhz, which makes it about 9.8 times faster than Z80. So, the "new"
MSX (ACE002) will be about 57% faster than TurboR in ROM mode.
Thinking on ADVRAM, it lets video working about 5 times faster than
normal video working (throught the ports), and we are talking about
a 3.57Mhz MSX! (-; I really don't know how to calculate how much faster
ADVRAM will be on an Z180 at 33Mhz MSX...
For those interested on how ADVRAM works, there is some information
at Ademir page ( http://www.carchano.com.br/ ). It does the trick
connecting the VRAM directly on the BUS, and you can read/write it as
you use a Mapper. More datails later.
Just a fact: These enhancements ARE possible, and Ademir is already
finishing ADVRAM. We will produce ADVRAM software using "normal 7Mhz
computers" and "Turbo Rs", until ACE002 is not ready. ACE002 will
take some more time due to the fact Ademir is recreating all MSX
processors using PLDs.
Stay tunned.
AbraçOS/2, Daniel Caetano ([EMAIL PROTECTED])
...!m.tag
OS/2 Sites: http://www.quasarbbs.com/daniel/
http://www.geocities.com/SiliconValley/8752/os2hp/os2index.html
MSX Sites: http://www.fudeba.cjb.net/
Drawings: http://www.djgallery.tsx.org/
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