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Author Re: S/360
robin

2006-01-16, 6:57 pm

"glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote in message
news:J6qdnbufBcshxVbenZ2dnUVZ_sSdnZ2d@co
mcast.com...
> John W. Kennedy wrote:
>
> Mantissa: The fractional part of a logarithm.


Also part of an FPN.

> Until a log instruction is implemented, you likely won't find the word
> mantissa in the Principles of Operations manual for any IBM processor.


Different manufacturers call the fields of an FPN different things.

You'll find "mantissa" used in any computer science text to
describe part of an FPN.

e.g. 1, Compuers & Programming, Hannula, 1974.
"The sign, the mantissa, and the characteristic of a floating-point
number are all stored in the same cell."
The diagrams show "mantissa" occupying bits 8 thru 31 and 8 thru 63.

e.g. 2, Rudd, Assembler Language Programming & the IBM 360 & 370, 1976.

Both books published in USA.

e.g. 3, Clone hardware ref manual:
For AE, AD, ADR, ADR: " If they [exponents] do not agree,
the mantissa with the smaller exponent operand is shifted right."

These were the first 3 books that I picked up.


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