kicad/eeschema/sim/user_defined_signals_help.md

SPICE functions:

sqrt(x)
sin(x)
cos(x)
tan(x)
sinh(x)
cosh(x)
tanh(x)
asin(x)
acos(x)
atan(x)
asinh(x)
acosh(x)
atanh(x)
arctan(x)
exp(x)
ln(x)
log(x)
abs(x)
nint(x)
int(x)
floor(x)
ceil(x)
pow(x, y)
pwr(x, y)
min(x, y)
max(x, y)
sgn(x)
ternary_fcn(x, y, z)
gauss(nom, rvar, sigma)
agauss(nom, avar, sigma)
unif(nom, rvar)
aunif(nom, avar)
limit(nom, avar)