first commit of the new libm!

[musl] / src / math / frexp.c

diff --git a/src/math/frexp.c b/src/math/frexp.c
new file mode 100644 (file)
index 0000000..27b6266
--- /dev/null
+++ b/src/math/frexp.c
@@ -0,0 +1,23 @@
+#include <math.h>
+#include <stdint.h>
+
+double frexp(double x, int *e)
+{
+       union { double d; uint64_t i; } y = { x };
+       int ee = y.i>>52 & 0x7ff;
+
+       if (!ee) {
+               if (x) {
+                       x = frexp(x*0x1p64, e);
+                       *e -= 64;
+               } else *e = 0;
+               return x;
+       } else if (ee == 0x7ff) {
+               return x;
+       }
+
+       *e = ee - 0x3fe;
+       y.i &= 0x800fffffffffffffull;
+       y.i |= 0x3fe0000000000000ull;
+       return y.d;
+}