add circuitpython code

1 files changed, 28 insertions, 0 deletions

diff --git a/circuitpython/lib/libm_dbl/rint.c b/circuitpython/lib/libm_dbl/rint.c
new file mode 100644
index 0000000..fbba390
--- /dev/null
+++ b/circuitpython/lib/libm_dbl/rint.c
@@ -0,0 +1,28 @@
+#include <float.h>
+#include <math.h>
+#include <stdint.h>
+
+#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
+#define EPS DBL_EPSILON
+#elif FLT_EVAL_METHOD==2
+#define EPS LDBL_EPSILON
+#endif
+static const double_t toint = 1/EPS;
+
+double rint(double x)
+{
+	union {double f; uint64_t i;} u = {x};
+	int e = u.i>>52 & 0x7ff;
+	int s = u.i>>63;
+	double_t y;
+
+	if (e >= 0x3ff+52)
+		return x;
+	if (s)
+		y = x - toint + toint;
+	else
+		y = x + toint - toint;
+	if (y == 0)
+		return s ? -0.0 : 0;
+	return y;
+}