On Fri, 21 Apr 2000 19:56:58 +0200, Laurens Holst wrote:
>- The Ademir ACE002 board can execute old programs fast, however there is no
>new instruction set.
Z180 has new instructions.
>The Z380 is fully compatible with the Z180. Therefor, all Z80 as well as all
>Z180 programs can be executed on it. The Z180 is fully compatible with the
>Z80, except for the undocumented instructions, which have to be remapped. So
>all Z80 programs can be run on an Z180+remap.
Z380 is not, AFAIK, 100% compatible with Z180.
>So when the Z380 runs at its full potential, it is almost as fast as the
>Z180 when executing old code. Maybe it's even closer to the Z180, it kinda
>depends on the instructions used.
On full potential, on complex 32 bit instructions (non-existent on Z180), Z380
may be faster (a lot faster) than Z180.
>Let's define more specificly: ACE002 is Ademir's current project. This
>project features an entirely new mainboard, and a fast CPU, namely the Z180,
>with the unsupported IXh/IXl registers remapped to their Z80 equivalents.
>However, no other new features.
ADVRAM will be integrated on the board. It's a new feature that everyone that
uses ACE002 will have.
>I think it is wise if Ademir and Padial would join efforts. Ademir is
>recreating the chips in PDL's (am I right?), he has the stuff for the
>mainboard. Padial has very good ideas about extending the MSX.
Maybe we can do the following: Ademir creates ACE002. And we plug Padial's
Z380 board on a 33Mhz slot of ACE002. (((-:
>- 32 bits slots, which also support old cartridges (LPE's).
32 bit cartridges slots...? For 4Gb access...?
>Ademir's ACE002 is a nice in-between form, but not a new standard. As he
>himself (through others) repeatedly said by the way.
Create a new standard is something complicated.
>Now, the 'enhanced' mode... I define 'enhanced' mode as the mode of both
>processors in which they have extra instructions available and a larger
>memory area. The instructions of the Z180 are the same as the ones of the
>Z380.
Are they?
> Therefor, there is nothing wrong with supporting the Z180's extra
>instructions (which are, by the way, not that much).
They are!!! (((-; He has Mult also... and Div, something Z80 is
very slooooooooooooooooow to do. The instructions Z380 performs
plus Z180 are high mathematics, almost never used. The better
part of Z380 over Z180 are the large amount of extra registers...
But also, I don't know if this can or cannot affect old programs
execution on the Enhanced mode (Z380).
> However, the adress
>range the Z180 has is -afaik- not really compatible with the Z380's... So I
>suggest you ignore my previous comments and don't add the extended adress
>range to the ACE002's features. 64k will do fine for MSX 2.7.
(-; I think 64Kb is good in a first step, to avoid bigger problems. BUt
this may be changed.
>ADVRAM is a nice idea, but as I said before:
>"I am not enthousiastic about ADVRAM. It's a nice feature, but that's all.
>It isn't backwards compatible, and it won't matter that much in speed
Who said you it's not bakcward compatible? It is... it just doesn't add
speed to legacy apps. But legacy apps may work with new apps, that uses
ADVRAM.
>So please Ademir, re-consider.
I think you have not got the ADVRAM idea. I think it's better than increasing
main processor speed. ((((-;
>About a slowdown to let the processor run at something around 3.5 MHz (1 MHz
>@ Z380???)...
No, you run it at the full speed, but turn on several Waits.
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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