/* Perform a "short reduction" in field F256 (field for curve P-256). The source value should be less than 262 bits; on output, it will be at most 257 bits, and less than twice the modulus.  */
static void reduce_f256(uint32_t *d)
/* Perform a "short reduction" in field F256 (field for curve P-256). The source value should be less than 262 bits; on output, it will be at most 257 bits, and less than twice the modulus.  */
static void reduce_f256(uint32_t *d)
{
	uint32_t x;
	x = d[19] >> 9;
	d[19] &= 0x01FF;
	d[17] += x << 3;
	d[14] -= x << 10;
	d[7] -= x << 5;
	d[0] += x;
	norm13(d, d, 20);
}