Numbers and bitwise functions.

 See NatInt/NZBits.v for the common axiomatization of bitwise functions
 over naturals / integers. Some specs aren't pretty, but easier to
 prove, see alternate statements in property functors {N,Z}Bits.
 Negative numbers are considered via the two's complement convention.

 We provide implementations for N (in Ndigits.v), for nat (quite dummy,
 just for completeness), for Z (new file Zdigits_def), for BigN
 (for the moment partly by converting to N, to be improved soon)
 and for BigZ.

 NOTA: For BigN.shiftl and BigN.shiftr, the two arguments are now in
 the reversed order (for consistency with the rest of the world):
 for instance BigN.shiftl 1 10 is 2^10.

 NOTA2: Zeven.Zdiv2 is _not_ doing (Zdiv _ 2), but rather (Zquot _ 2)
 on negative numbers. For the moment I've kept it intact, and have
 just added a Zdiv2' which is truly equivalent to (Zdiv _ 2).
 To reorganize someday ?

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@13689 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 1 insertions, 1 deletions

diff --git a/theories/NArith/Ndist.v b/theories/NArith/Ndist.v
index 0b61718f8..9d399f5cd 100644
--- a/theories/NArith/Ndist.v
+++ b/theories/NArith/Ndist.v
@@ -301,7 +301,7 @@ Proof.
   cut (forall a'':N, Nxor (Npos p) a' = a'' -> Nbit a'' k = false).
   intros. apply H1. reflexivity.
   intro a''. case a''. intro. reflexivity.
-  intros. rewrite <- H1. rewrite (Nxor_semantics (Npos p) a' k). unfold xorf in |- *.
+  intros. rewrite <- H1. rewrite (Nxor_semantics (Npos p) a' k).
   rewrite
    (Nplength_zeros (Npos p) (Pplength p)
       (refl_equal (Nplength (Npos p))) k H0).