cexp
double complex cexp(double complex);
static const fixpt_t cexp[ ] = {
CTASSERT(__arraycount(cexp) == __arraycount(avg->ldavg));
for (i = 0; i < __arraycount(cexp); i++) {
avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;