math: raise invalid flag in ilogb*.c on +-0, +-inf and nan

[musl] / src / math / expm1l.c

diff --git a/src/math/expm1l.c b/src/math/expm1l.c
index 2f94dfa..21a86c0 100644 (file)
--- a/src/math/expm1l.c
+++ b/src/math/expm1l.c
@@ -44,13 +44,7 @@
  *
  *                      Relative error:
  * arithmetic   domain     # trials      peak         rms
- *    IEEE    -45,+MAXLOG   200,000     1.2e-19     2.5e-20
- *
- * ERROR MESSAGES:
- *
- *   message         condition      value returned
- * expm1l overflow   x > MAXLOG         MAXNUM
- *
+ *    IEEE    -45,+maxarg   200,000     1.2e-19     2.5e-20
  */
 
 #include "libm.h"
@@ -61,7 +55,6 @@ long double expm1l(long double x)
        return expm1(x);
 }
 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
-static const long double MAXLOGL = 1.1356523406294143949492E4L;
 
 /* exp(x) - 1 = x + 0.5 x^2 + x^3 P(x)/Q(x)
    -.5 ln 2  <  x  <  .5 ln 2
@@ -83,25 +76,26 @@ C1 = 6.93145751953125E-1L,
 C2 = 1.428606820309417232121458176568075500134E-6L,
 /* ln 2^-65 */
 minarg = -4.5054566736396445112120088E1L,
-huge = 0x1p10000L;
+/* ln 2^16384 */
+maxarg = 1.1356523406294143949492E4L;
 
 long double expm1l(long double x)
 {
        long double px, qx, xx;
        int k;
 
-       /* Overflow.  */
-       if (x > MAXLOGL)
-               return huge*huge;  /* overflow */
+       if (isnan(x))
+               return x;
+       if (x > maxarg)
+               return x*0x1p16383L; /* overflow, unless x==inf */
        if (x == 0.0)
                return x;
-       /* Minimum value.*/
        if (x < minarg)
-               return -1.0L;
+               return -1.0;
 
        xx = C1 + C2;
        /* Express x = ln 2 (k + remainder), remainder not exceeding 1/2. */
-       px = floorl (0.5 + x / xx);
+       px = floorl(0.5 + x / xx);
        k = px;
        /* remainder times ln 2 */
        x -= px * C1;
@@ -116,7 +110,7 @@ long double expm1l(long double x)
        /* exp(x) = exp(k ln 2) exp(remainder ln 2) = 2^k exp(remainder ln 2).
         We have qx = exp(remainder ln 2) - 1, so
         exp(x) - 1  =  2^k (qx + 1) - 1  =  2^k qx + 2^k - 1.  */
-       px = ldexpl(1.0L, k);
+       px = scalbnl(1.0, k);
        x = px * qx + (px - 1.0);
        return x;
 }