floorf
float floorf(float);
DEF_STD(floorf);
PROTO_NORMAL(floorf);
z = floorf(y);
y = (float)2.0*(y - floorf(y)); /* y = |x| mod 2.0 */
z -= (float)8.0*floorf(z*(float)0.125); /* trim off integer >= 8 */
DEF_STD(floorf);
t = floorf(x);
t = floorf(-x);
floorf((__real__ (f)) * PREC) == floorf((r) * PREC) && \
floorf((__imag__ (f)) * PREC) == floorf((i) * PREC) \