1 #include "fe.h"
2 
3 /*
4 return 1 if f is in {1,3,5,...,q-2}
5 return 0 if f is in {0,2,4,...,q-1}
6 
7 Preconditions:
8    |f| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
9 */
10 
fe_isnegative(const fe f)11 int fe_isnegative(const fe f)
12 {
13   unsigned char s[32];
14   fe_tobytes(s,f);
15   return s[0] & 1;
16 }
17