shift right arithmetic

[Theodore A. Camus]

I would like to do a portable arithmetic right shift in C.


Possible solutions and problems :

1) '>>' will _not_ guarantee the result on a signed argument (ANSI & K&R)

2) dividing by a power of 2 will often compile to arithmetic shifts, but 
   only for the smaller powers of 2, not for the full 2^1 - 2^31 shift range.

3) One could test for a negative argument, and if it was negative, use a
   negate / shift / negate sequence, but there should be a better way.


For most compilers, '>>' will differentiate between signed and unsigned
arguments, but again K&R and ANSI allows it to be implementation-defined.

Any answers ?

        - Ted


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