On 14/03/2012 09:11, Mark wrote:
On Mon, 12 Mar 2012 12:36:08 GMT, lid
(Windmill) wrote:

Tim writes:

In articleOvGdna0mRsnxasHSnZ2dnUVZ8gOdnZ2d@brightvie w.co.uk,
John wrote:

On 11/03/2012 05:26, Windmill wrote:
John writes:

On 10/03/2012 17:48, Jules Richardson wrote:
On Sat, 10 Mar 2012 13:33:46 +0000, John Rumm wrote:
;-) Rather like talking with IMB mid range / mainframe types who seem
convinced that Assembler (note the capital A!) can only be known to
hallowed IBM programmers, and can't seem to get their heads round the
fact that every processor has a low level assembly language...

Every? Depends on the definition of assembly language, I suppose - is it
the binary opcodes which form CPU instructions, or is it the human-
readable mnemonics which correspond to those opcodes?

The latter...

I usually think of assembly language as the latter (that being what
people program at the low level using), but I suppose it's entirely
possible to have a CPU where there are no official published mnemonics
and instead things are documented in a more long-winded "binary opcode xx
performs operation yy" form.

I find it hard to imaging how you would document a processor instruction
set without in the process creating its assembly language as a result...
I suppose you could describe every instruction longhand, but I can't
imagine it would be long before some one comes along and creates
mnemonics for each.

ISTR some sort of 8 bit CPU (? Z80 ?) whose documentation included a
description in BNF.

Yup, used to be quite common, but does not seem to get much of an outing
these days. Not sure if I ever had the official Zilog books on the Z80,
although I have got Zaks, and that may well "borrow" the official
language description as many books of its day did.

BNF is a bit turgid to read. May as well use mnemonics.

I suspect it's because of a limited capacity to keep large amounts of
stuff in mind, but I've always preferred high-density information to
the wordy stuff; BNF isn't an easy read, but in younger days I could
puzzle my way through it with some effort.

BNF can be very useful if you are writing a parser.

Yup, formal language specs are probably what its best at... limited
audience perhaps though.

--
Cheers,

John.

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