X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/075af3599557e6e480049137c0e316c1de1abf93..7b0d1a63587f3cb1ae3bb8b248bbb1b82bdca7bd:/math/mp-jacobi.c

diff --git a/math/mp-jacobi.c b/math/mp-jacobi.c
index b1b02163..29920760 100644
--- a/math/mp-jacobi.c
+++ b/math/mp-jacobi.c
@@ -59,7 +59,7 @@
  *		    congruent to 1 or 7 (mod 8), or %$-1$% otherwise.
  *
  *		If %$n$% is positive and odd, then this is the Jacobi
- *		symbol.  (The Kronecker symbol is a consistant domain
+ *		symbol.  (The Kronecker symbol is a consistent domain
  *		extension; the Jacobi symbol was implemented first, and the
  *		name stuck.)
  */
@@ -130,7 +130,7 @@ int mp_jacobi(mp *a, mp *n)
       goto done;
     }
 
-    /* --- Main case with powers of two --- */
+    /* --- Strip out powers of two from %$a$% --- */
 
     a = mp_odd(a, a, &e);
     nn = n->v[0] & 7;
@@ -138,11 +138,11 @@ int mp_jacobi(mp *a, mp *n)
       s = -s;
     if (MP_LEN(a) == 1 && a->v[0] == 1)
       goto done;
-    if ((nn & 3) == 3 && (a->v[0] & 3) == 3)
-      s = -s;
 
-    /* --- Reduce and swap --- */
+    /* --- Reduce and swap, applying quadratic residuosity --- */
 
+    if ((nn & 3) == 3 && (a->v[0] & 3) == 3)
+      s = -s;
     mp_div(0, &n, n, a);
     { mp *t = n; n = a; a = t; }
   }