How does one construct a mask for th

Ron Natalie <ron> ron at brl-tgr.ARPA
Thu Mar 7 03:05:14 AEST 1985


> >> /*
> >> This would require generation of a mask for the most significant bit
> >> */
> 
> #define MSB (~(-1>>1))
> 
Surprise, this doesn't even work on VAX's and PDP -11's.  -1>>1 is still
-1.  Be careful when coming up with ideas like these.  C has also been
implemented on ones-complement (and subtractive arithmatic) machines.
Right shifting of signed quantities is defined to be machine depenedant
in C.

-Ron



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