#ifndef FE_H
#define FE_H

#include <stdint.h>

/*
fe means field element.
Here the field is \Z/(2^255-19).
An element t, entries t[0]...t[9], represents the integer
t[0]+2^26 t[1]+2^51 t[2]+2^77 t[3]+2^102 t[4]+...+2^230 t[9].
Bounds on each t[i] vary depending on context.
*/
int x25519(unsigned char *q, const unsigned char *n, const unsigned char *p);

void fe_frombytes(int32_t fe[10], const unsigned char *);
void fe_tobytes(unsigned char *, int32_t fe[10]);

void fe_copy(int32_t dest[10], int32_t src[10]);
void fe_0(int32_t fe[10]);
void fe_1(int32_t fe[10]);
void fe_cswap(int32_t a[10], int32_t b[10], unsigned int);

void fe_add(int32_t dest[10], int32_t a[10], int32_t b[10]);
void fe_sub(int32_t dest[10], int32_t a[10], int32_t b[10]);
void fe_mul(int32_t dest[10], int32_t a[10], int32_t b[10]);
void fe_sq(int32_t dest[10], int32_t a[10]);
void fe_mul121666(int32_t dest[10], int32_t a[10]);
void fe_invert(int32_t dest[10], int32_t a[10]);

#endif