Lines Matching defs:log2
1966 * log2(x) = (f - 0.5*f*f + k_log1p(f)) / ln2 + k
1969 double log2(double x) {
2557 // |x| in [0,0.5*log2], return 1+expm1(|x|)^2/(2*exp(|x|))
2566 // |x| in [0.5*log2, 22], return (exp(|x|)+1/exp(|x|)/2
2597 * 1. Compute and return log2(x) in two pieces:
2598 * log2(x) = w1 + w2,
2600 * 2. Perform y*log2(x) = n+y' by simulating muti-precision
2602 * 3. Return x**y = 2**n*exp(y'*log2)
2660 ovt = 8.0085662595372944372e-0017, // -(1024-log2(ovfl+.5ulp))
2830 /* 2/(3log2)*(ss+...) */
2834 z_h = cp_h * p_h; /* cp_h+cp_l = 2/(3*log2) */
2836 /* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */