-/*
- * exp2f(x): compute the base 2 exponential of x
- *
- * Accuracy: Peak error < 0.501 ulp; location of peak: -0.030110927.
- *
- * Method: (equally-spaced tables)
- *
- * Reduce x:
- * x = 2**k + y, for integer k and |y| <= 1/2.
- * Thus we have exp2f(x) = 2**k * exp2(y).
- *
- * Reduce y:
- * y = i/TBLSIZE + z for integer i near y * TBLSIZE.
- * Thus we have exp2(y) = exp2(i/TBLSIZE) * exp2(z),
- * with |z| <= 2**-(TBLSIZE+1).
- *
- * We compute exp2(i/TBLSIZE) via table lookup and exp2(z) via a
- * degree-4 minimax polynomial with maximum error under 1.4 * 2**-33.
- * Using double precision for everything except the reduction makes
- * roundoff error insignificant and simplifies the scaling step.
- *
- * This method is due to Tang, but I do not use his suggested parameters:
- *
- * Tang, P. Table-driven Implementation of the Exponential Function
- * in IEEE Floating-Point Arithmetic. TOMS 15(2), 144-157 (1989).
- */