🚀 go-pugleaf

>>>>> "Bill" == Bill Williams (bwilliam@iat.holonet.net)

Bill> re : "1)  I believe that the Acorn 610 has a 4k on chip cache."

Bill> Yeah right!

Bill> It has only 32000 transistors yet can magically support 4096 bytes of
Bill> cache RAM in the 32000 transistors... 
Bill> [...]
Bill> SOMEONE OUT THERE IS A LIAR!!!! I assume the liar is Acorn, and that the
Bill> chip has 500,000 transistors and not the 32000 transistors claimed.

Now, let's try to get this right:

 - The ARM is a CPU architecture, designed by Acorn, later sold to
   Advanced Risc Machines, a company owned by Olivetti, Apple, and
   VLSI Logic (Acorn has been taken over by Olivetti).

 - There has been a number of implementation of the ARM architecture
   developed by Acorn and manufactured by VLSI Logic (ARM 1, 2, 3).
   The ARM3 chip design has been handed over to Advanced Risc
   Machines and is the current chip used by Acorn for their Archimedes
   range.

 - ARM6 is a macro cell implementation of the ARM architecture. A
   macro cell is sort of a VLSI module, something you can take as a
   components and plug into an ASIC (Application Specific IC). It's
   *not* a chip, it's a chip modules. It's a complete CPU.

 - ARM6 has 36000 transistors.

 - You can call Advanced Risc Machines and order a ASIC that includes
   ARM6 as a component. You specify what else goes there, depending
   on what you need. Might be a UART or a MMU or video controller or
   something else. This allows Advanced Risc Machines to sell the same
   architecture to people that build industrial control electronics
   and people that build laser printers.

 - ARM610 is a specific chip build is this way, using the ARM6 macro
   cell. The ARM610 also includes a rather strange MMU that is
   supposed to be great for OO -- it has a protection system that is
   orthogonal to the paging system. I don't really understand how this
   works just yet -- I'll have to get more specs. The ARM610 also
   includes a 4 kbyte, 64 way cache. The cache is small and many-way
   to save power. The ARM610 is completely static and has advanced
   control logic that allows the clock to be changed and stopped at
   any state and other niceties to save power.

 - ARM610 does not take advantage of all ARM6 features. It does not
   support the coprocessor interface.

 - There is no such things as an Acorn 610, so I can hardly see Acorn
   being a liar in this matter :-)

/Lars
--
Lars Fischer, fischer@iesd.auc.dk | It takes an uncommon mind to think of
CS Dept., Aalborg Univ., DENMARK. | these things.  -- Calvin