1 files changed, 27 insertions, 0 deletions
diff --git a/winsup/mingw/mingwex/math/acoshl.c b/winsup/mingw/mingwex/math/acoshl.c
new file mode 100755
index 000000000..c461176bb
--- /dev/null
+++ b/winsup/mingw/mingwex/math/acoshl.c
@@ -0,0 +1,27 @@
+#include <math.h>
+#include <errno.h>
+#include "fastmath.h"
+
+/* acosh(x) = log (x + sqrt(x * x - 1)) */
+long double acoshl (long double x)
+{
+  if (isnan (x)) 
+    return x;
+
+  if (x < 1.0L)
+    {
+      errno = EDOM;
+      return nanl("");
+    }
+  if (x > 0x1p32L)
+    /* Avoid overflow (and unnecessary calculation when
+       sqrt (x * x - 1) == x).
+       The M_LN2 define doesn't have enough precison for
+       long double so use this one. GCC optimizes by replacing
+       the const with a fldln2 insn. */
+    return __fast_logl (x) + 6.9314718055994530941723E-1L;
+
+   /* Since  x >= 1, the arg to log will always be greater than
+      the fyl2xp1 limit (approx 0.29) so just use logl. */ 
+   return __fast_logl (x + __fast_sqrtl((x + 1.0L) * (x - 1.0L)));
+}