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-rw-r--r--lib/mlibc/options/ansi/musl-generic-math/acoshl.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/acoshl.c b/lib/mlibc/options/ansi/musl-generic-math/acoshl.c
new file mode 100644
index 0000000..8d4b43f
--- /dev/null
+++ b/lib/mlibc/options/ansi/musl-generic-math/acoshl.c
@@ -0,0 +1,29 @@
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double acoshl(long double x)
+{
+ return acosh(x);
+}
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
+/* acosh(x) = log(x + sqrt(x*x-1)) */
+long double acoshl(long double x)
+{
+ union ldshape u = {x};
+ int e = u.i.se & 0x7fff;
+
+ if (e < 0x3fff + 1)
+ /* |x| < 2, invalid if x < 1 or nan */
+ return log1pl(x-1 + sqrtl((x-1)*(x-1)+2*(x-1)));
+ if (e < 0x3fff + 32)
+ /* |x| < 0x1p32 */
+ return logl(2*x - 1/(x+sqrtl(x*x-1)));
+ return logl(x) + 0.693147180559945309417232121458176568L;
+}
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+// TODO: broken implementation to make things compile
+long double acoshl(long double x)
+{
+ return acosh(x);
+}
+#endif