ape/libm: add back fmod, remove modf

We removed the wrong file. Put it back.

1 files changed, 27 insertions, 0 deletions

diff --git a/sys/src/ape/lib/ap/math/fmod.c b/sys/src/ape/lib/ap/math/fmod.c
new file mode 100644
index 000000000..876c64c39
--- /dev/null
+++ b/sys/src/ape/lib/ap/math/fmod.c
@@ -0,0 +1,27 @@
+/* floating-point mod function without infinity or NaN checking */
+#include <math.h>
+double
+fmod (double x, double y)
+{
+	int sign = 0, yexp;
+	double r, yfr;
+
+	if (y == 0)
+		return 0;
+	if (y < 0)
+		y = -y;
+	yfr = frexp (y, &yexp);
+	if (x < 0) {
+		sign = 1;
+		r = -x;
+	} else
+		r = x;
+	while (r >= y) {
+		int rexp;
+		double rfr = frexp (r, &rexp);
+		r -= ldexp (y, rexp - yexp - (rfr < yfr));
+	}
+	if (sign)
+		r = -r;
+	return r;
+}