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-rw-r--r--src/math/s_scalblnf.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/src/math/s_scalblnf.c b/src/math/s_scalblnf.c
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+++ b/src/math/s_scalblnf.c
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+/* s_scalbnf.c -- float version of s_scalbn.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 <math.h>
+#include "math_private.h"
+
+static const float
+two25 = 3.355443200e+07, /* 0x4c000000 */
+twom25 = 2.9802322388e-08, /* 0x33000000 */
+huge = 1.0e+30,
+tiny = 1.0e-30;
+
+float
+scalblnf (float x, long n)
+{
+ int32_t k,ix;
+ GET_FLOAT_WORD(ix,x);
+ k = (ix&0x7f800000)>>23; /* extract exponent */
+ if (k==0) { /* 0 or subnormal x */
+ if ((ix&0x7fffffff)==0) return x; /* +-0 */
+ x *= two25;
+ GET_FLOAT_WORD(ix,x);
+ k = ((ix&0x7f800000)>>23) - 25;
+ if (n< -50000) return tiny*x; /*underflow*/
+ }
+ if (k==0xff) return x+x; /* NaN or Inf */
+ k = k+n;
+ if (k > 0xfe) return huge*copysignf(huge,x); /* overflow */
+ if (k > 0) /* normal result */
+ {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
+ if (k <= -25) {
+ if (n > 50000) /* in case integer overflow in n+k */
+ return huge*copysignf(huge,x); /*overflow*/
+ else return tiny*copysignf(tiny,x); /*underflow*/
+ }
+ k += 25; /* subnormal result */
+ SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
+ return x*twom25;
+}
+
+float
+scalbnf (float x, int n)
+{
+ return scalblnf(x, n);
+}