1 files changed, 64 insertions, 0 deletions
diff --git a/src/math/remainderf.c b/src/math/remainderf.c
new file mode 100644
index 00000000..c17bb4f4
--- /dev/null
+++ b/src/math/remainderf.c
@@ -0,0 +1,64 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_remainderf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#include "libm.h"
+
+static const float zero = 0.0;
+
+float remainderf(float x, float p)
+{
+	int32_t hx,hp;
+	uint32_t sx;
+	float p_half;
+
+	GET_FLOAT_WORD(hx, x);
+	GET_FLOAT_WORD(hp, p);
+	sx = hx & 0x80000000;
+	hp &= 0x7fffffff;
+	hx &= 0x7fffffff;
+
+	/* purge off exception values */
+	if (hp == 0)  /* p = 0 */
+		return (x*p)/(x*p);
+	if (hx >= 0x7f800000 || hp > 0x7f800000)  /* x not finite, p is NaN */
+		// FIXME: why long double?
+		return ((long double)x*p)/((long double)x*p);
+
+	if (hp <= 0x7effffff)
+		x = fmodf(x, p + p);  /* now x < 2p */
+	if (hx - hp == 0)
+		return zero*x;
+	x = fabsf(x);
+	p = fabsf(p);
+	if (hp < 0x01000000) {
+		if (x + x > p) {
+			x -= p;
+			if (x + x >= p)
+				x -= p;
+		}
+	} else {
+		p_half = (float)0.5*p;
+		if (x > p_half) {
+			x -= p;
+			if (x >= p_half)
+				x -= p;
+		}
+	}
+	GET_FLOAT_WORD(hx, x);
+	if ((hx & 0x7fffffff) == 0)
+		hx = 0;
+	SET_FLOAT_WORD(x, hx ^ sx);
+	return x;
+}