Hi all,

I get a weird behavior when using bitwise-ior and bitwise-and with large 
numbers. Tested on 2 machines (racket 6.6, Ubuntu 16.04 and 14.04):

Here is the test example:

#lang racket
(define num #xffffffffffffffff) ;; remove one f, and the results are fine 
in both cases
(for ([i 5])
  (printf "~a~n" (bitwise-ior (bitwise-and num -2) 0)))


When run from DrRacket using ctr+r, it works properly:
18446744073709551614
18446744073709551614
18446744073709551614
18446744073709551614
18446744073709551614

When pasted into DrRacket's REPL (or run from command line via "racket 
random-bug.rkt"), the code does not only produce wrong result, but also 
seems to be counting something :)
70112357026588
70112357038692
70112357043588
70112357048576
70112357053344

Removing one "f" from the test number results in correct behavior in both 
cases.
Very large numbers are are reduced to the same range (around 54 bits).
Replacing the expression (bitwise-and num -2) by the corresponding number 
it computes results in correct behavior.

Cheers,
Peter

-- 
You received this message because you are subscribed to the Google Groups 
"Racket Developers" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to racket-dev+unsubscr...@googlegroups.com.
To post to this group, send email to racket-dev@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/racket-dev/d0310d90-0d88-4902-b430-0069b310d7a3%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to