title: SRSHIFT

description:

 SRSHIFT                             "s-r-shift"

 ( x1 u -- x2 )

 Perform an arithmetic right shift of u bit-places on x1, giving x2.
 (On one's complement and two's complement machines this means: copy
 the sign bit into the most significant bits vacated by the shift.)  An
 ambiguous condition exists if u is greater than or equal to the number
 of bits in a cell.


discussion-of-name:

 SRSHIFT stands for "Signed Right SHIFT". Usually this is called
 "arithmetic shift", but we cannot derive a Forth name from this
 because of the following consideration.

"Michael L.Gassanenko" wrote:

 [why not ARSHIFT or ASHIFT ]

> The problem is that Russian/German/French speakers are likely to pronounce
> ASHIFT so that you, American English speaker, would understand it as RSHIFT.
> And vice versa, when an English speaker says RSHIFT, a Russian/German/French
> speaker may hear ASHIFT.
> (The same about ARSHIFT: you pronounce 'r' as "ar", don't you?)
>
> Things get even worse with two Russian/German/French speakers:
> one cannot be sure whether the other speaks with or without
> an accent. And if you remember that the other person may try
> to correct his/her pronunciation but not be consistent...

discussion-of-functionality:

 The rounding direction (towards zero or towards minus infinity)
 depends on the platform (one's complement or two's complement).

 For a discussion of arithmetic shift problems, see
 http://forth.sourceforge.net/Standard%2B/two-slash/index.html