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-rw-r--r--src/math/nextafterf.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/src/math/nextafterf.c b/src/math/nextafterf.c
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--- /dev/null
+++ b/src/math/nextafterf.c
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+/* origin: FreeBSD /usr/src/lib/msun/src/s_nextafterf.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"
+
+float nextafterf(float x, float y)
+{
+	volatile float t;
+	int32_t hx,hy,ix,iy;
+
+	GET_FLOAT_WORD(hx, x);
+	GET_FLOAT_WORD(hy, y);
+	ix = hx & 0x7fffffff;  /* |x| */
+	iy = hy & 0x7fffffff;  /* |y| */
+
+	if (ix > 0x7f800000 || /* x is nan */
+	    iy > 0x7f800000)   /* y is nan */
+		return x+y;
+	if (x == y)            /* x == y */
+		return y;
+	if (ix == 0) {         /* x == 0 */
+		SET_FLOAT_WORD(x, (hy&0x80000000)|1); /* return +-minsubnormal */
+		/* raise underflow flag */
+		t = x*x;
+		if (t == x)
+			return t;
+		return x;
+	}
+	if (hx >= 0) {         /* x > 0 */
+		if (hx > hy) {             /* x > y, x -= ulp */
+			hx--;
+		} else {                   /* x < y, x += ulp */
+			hx++;
+		}
+	} else {               /* x < 0 */
+		if (hy >= 0 || hx > hy) {  /* x < y, x -= ulp */
+			hx--;
+		} else {                   /* x > y, x += ulp */
+			hx++;
+		}
+	}
+	hy = hx & 0x7f800000;
+	if (hy >= 0x7f800000)  /* overflow */
+		return x+x;
+	if (hy < 0x00800000) { /* underflow */
+		/* raise underflow flag */
+		t = x*x;
+		if (t != x) {
+			SET_FLOAT_WORD(y, hx);
+			return y;
+		}
+	}
+	SET_FLOAT_WORD(x, hx);
+	return x;
+}