[Oberon] Re (2): RISC-5; was RISC5

[Skulski, Wojciech]

The NW text RISC.pdf says on page 2 that progression from RISC-3 to RISC-5 does not involve the processor itself, but rather adding peripherals to the same processor. Now imagine that one adds another peripheral interface to the system, like for example I2C or an analog converter. Should the resultant system be called RISC-6? What will happen if someone adds an ADC, while someone else adds a DAC? Are we talking of  RISC-6 and RISC-7, or perhaps RISC-6A and RISC-6B?

In my mind progression from RISC-5 to a hypothetical RISC-6, RISC-7, etc, would be justified if the CPU itself is changing (e.g., adding a new instruction opcode). My thinking is that RISC-5 is the processor, while adding peripherals to the processor is the Oberon System with add-ons. Adding the peripherals should not cause bumping up the processor number version. But this is not what the NW test is saying on page 2.  

It may seem moot. However, the current approach is inviting confusion, as the recent post by Chris is implying. Chris said that his Astrobe design is not really RISC-5, but some sort of RISC without a clear number. So it is not clear where to place Chris' development in the hardware inheritance tree.

W.
________________________________________
From: Oberon [oberon-bounces at lists.inf.ethz.ch] on behalf of peter at easthope.ca [peter at easthope.ca]
Sent: Monday, September 12, 2016 9:36 AM
To: oberon at lists.inf.ethz.ch
Subject: [Oberon] Re (2):  RISC-5; was RISC5

From:   Pablo Cayuela <pablo.cayuela at gmail.com>, Sat, 10 Sep 2016 19:46:12 -0300
> You could check Wirth's RISC versions here:
> https://www.inf.ethz.ch/personal/wirth/FPGA-relatedWork/RISC.pdf

Thanks Pablo.  The glossary entry in https://en.wikipedia.org/wiki/Oberon_%28operating_system%29
now has the directory.  Googling "risc-5" yields the article as the third result
with the extract including "RISC-5".

                                        ... Lyall E.

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