rpcorbett at att.net
Tue Oct 13 07:07:10 EDT 2020
I agree that there is no need to
support such machines. If we
do not, we should say we do not.
The IBM 1620 used six bits to
store one decimal digit, a flag,
and a parity bit. The flag bit
could be a sign bit or a
field terminator. Not all
combinations of bits were
allowed. Some special bit
sequences had special
properties, and others were
not used at all during normal
execution. The four bits used
to represent a decimal digit
could not represent the
values 10 - 15, which limits
their use for bitwise operations.
> On Oct 13, 2020, at 12:51 AM, Malcolm Cohen via J3 <j3 at mailman.j3-fortran.org> wrote:
> I don’t think those machines are coming back, so it’s hard to feel too worried about this kind of thing...
> And they are not decimal machines for storage. They are binary, with (if I read the doc correctly) eight bits per location, though one of those bits is parity. STORAGE_SIZE should return the number of bits of storage...
> I’m not seeing a problem here, but maybe I’m not looking hard enough.
> ..............Malcolm Cohen, NAG Oxford/Tokyo.
> From: J3 <j3-bounces at mailman.j3-fortran.org> On Behalf Of Robert Corbett via J3
> Sent: Tuesday, October 13, 2020 3:29 PM
> To: j3 at j3-fortran.org
> Cc: Robert Corbett <rpcorbett at att.net>
> Subject: [J3] STORAGE_SIZE
> The intrinsic function
> STORAGE_SIZE returns the
> size of an array element in
> bits. Machines such as the
> IBM 1401 and the IBM 1620
> stored data as decimal
> digits instead of bits. Should
> we say that STORAGE_SIZE
> is processor dependent on
> such machines?
> Robert Corbett
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