Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.forth
Subject: Re: Ting's EP32 32 Bit Processor IP with eForth eBook is available now and the Project page started
Date: Sun, 23 Apr 2017 14:27:33 -0700
Organization: A noiseless patient Spider
Lines: 8
Message-ID: <87o9vm95mi.fsf@nightsong.com>
References: <d9685ded-dac2-4646-8549-e56eb0d921d4@googlegroups.com> <ode2ej$80l$1@dont-email.me> <odg8br$akh$1@dont-email.me> <odgc12$m92$1@dont-email.me> <odha1o$4e1$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain
Injection-Info: mx02.eternal-september.org; posting-host="08059055d7485c5edb34280168da8ad3"; logging-data="14381"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18aMJt4KIMVoREl2TB9clRW"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)
Cancel-Lock: sha1:ONj4+oEekZ5P9ZTXTsoIFo99Q1U= sha1:OeaURVwG/Ek2/oi09Cdd5MmVWkc=
Xref: csiph.com comp.lang.forth:57927

rickman <gnuarm@gmail.com> writes:
> Usually instruction sets are extended because the designer has a
> emotional objection to leaving an instruction out.

In an FPGA cpu, I can see some value in leaving unused opcode space so
that the user can add application-specialized instructions.  Also, as
Cecil said, it's preferable to implement the instructions in common use,
rather than just the minimal set that can synthesize the common ones.