1 files changed, 62 insertions, 0 deletions
diff --git a/src/math/nexttowardf.c b/src/math/nexttowardf.c
new file mode 100644
index 00000000..c52ef3aa
--- /dev/null
+++ b/src/math/nexttowardf.c
@@ -0,0 +1,62 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_nexttowardf.c */
+/*
+ * ====================================================
+ * 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"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+// FIXME
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+#define LDBL_INFNAN_EXP (LDBL_MAX_EXP * 2 - 1)
+
+float nexttowardf(float x, long double y)
+{
+	union IEEEl2bits uy;
+	volatile float t;
+	int32_t hx,ix;
+
+	GET_FLOAT_WORD(hx, x);
+	ix = hx & 0x7fffffff;  /* |x| */
+	uy.e = y;
+
+	if (ix > 0x7f800000 ||
+	    (uy.bits.exp == LDBL_INFNAN_EXP &&
+	     ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0))
+		return x + y;  /* x or y is nan */
+	if (x == y)
+		return (float)y;  /* x=y, return y */
+	if (ix == 0) {   /* x == 0 */
+		SET_FLOAT_WORD(x, (uy.bits.sign<<31)|1); /* return +-minsubnormal */
+		/* raise underflow flag */
+		t = x*x;
+		if (t == x)
+			return t;
+		return x;
+	}
+	if (hx >= 0 ^ x < y)  /* x -= ulp */
+		hx--;
+	else                  /* x += ulp */
+		hx++;
+	ix = hx & 0x7f800000;
+	if (ix >= 0x7f800000)  /* overflow  */
+		return x+x;
+	if (ix < 0x00800000) { /* underflow */
+		/* raise underflow flag */
+		t = x*x;
+		if (t != x) {
+			SET_FLOAT_WORD(x, hx);
+			return x;
+		}
+	}
+	SET_FLOAT_WORD(x, hx);
+	return x;
+}
+#endif