x[(FRAC - i * 4 - 4) / mpbpl] |= (strchr (hexdig, str[i + 1]) - hexdig
x[(FRAC - i * 4 - 4) / mpbpl] |= ((strchr (hexdig, str[i + 1]) - hexdig)
read_mpn_hex(mp_limb_t *x, const char *str){  int i;  memset (x, 0, sizeof (mp1));  for (i = -1; i < 100 && i < FRAC / 4; ++i)    x[(FRAC - i * 4 - 4) / mpbpl] |= (strchr (hexdig, str[i + 1]) - hexdig				      << (FRAC - i * 4 - 4) % mpbpl);}