long double log10l(long double x)
{
- long double y;
- volatile long double z;
+ long double y, z;
int e;
if (isnan(x))
return x;
- if(x <= 0.0L) {
- if(x == 0.0L)
- return -1.0L / (x - x);
- return (x - x) / (x - x);
+ if(x <= 0.0) {
+ if(x == 0.0)
+ return -1.0 / (x*x);
+ return (x - x) / 0.0;
}
if (x == INFINITY)
return INFINITY;
if (e > 2 || e < -2) {
if (x < SQRTH) { /* 2(2x-1)/(2x+1) */
e -= 1;
- z = x - 0.5L;
- y = 0.5L * z + 0.5L;
+ z = x - 0.5;
+ y = 0.5 * z + 0.5;
} else { /* 2 (x-1)/(x+1) */
- z = x - 0.5L;
- z -= 0.5L;
- y = 0.5L * x + 0.5L;
+ z = x - 0.5;
+ z -= 0.5;
+ y = 0.5 * x + 0.5;
}
x = z / y;
z = x*x;
/* logarithm using log(1+x) = x - .5x**2 + x**3 P(x)/Q(x) */
if (x < SQRTH) {
e -= 1;
- x = ldexpl(x, 1) - 1.0L; /* 2x - 1 */
+ x = 2.0*x - 1.0;
} else {
- x = x - 1.0L;
+ x = x - 1.0;
}
z = x*x;
y = x * (z * __polevll(x, P, 6) / __p1evll(x, Q, 7));
- y = y - ldexpl(z, -1); /* -0.5x^2 + ... */
+ y = y - 0.5*z;
done:
/* Multiply log of fraction by log10(e)
z += e * (L102A);
return z;
}
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+// TODO: broken implementation to make things compile
+long double log10l(long double x)
+{
+ return log10(x);
+}
#endif