File: fe_isnegative.c

package info (click to toggle)
python-axolotl-curve25519 0.1-2~bpo8%2B1
  • links: PTS, VCS
  • area: main
  • in suites: jessie-backports
  • size: 624 kB
  • sloc: ansic: 4,750; python: 25; makefile: 4
file content (16 lines) | stat: -rw-r--r-- 266 bytes parent folder | download | duplicates (45)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
#include "fe.h"

/*
return 1 if f is in {1,3,5,...,q-2}
return 0 if f is in {0,2,4,...,q-1}

Preconditions:
   |f| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
*/

int fe_isnegative(const fe f)
{
  unsigned char s[32];
  fe_tobytes(s,f);
  return s[0] & 1;
}