diff options
Diffstat (limited to 'StdLib/LibC/Math/s_frexp.c')
-rw-r--r-- | StdLib/LibC/Math/s_frexp.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/StdLib/LibC/Math/s_frexp.c b/StdLib/LibC/Math/s_frexp.c new file mode 100644 index 0000000000..8e93600ef9 --- /dev/null +++ b/StdLib/LibC/Math/s_frexp.c @@ -0,0 +1,52 @@ +/* @(#)s_frexp.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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 <LibConfig.h>
+#include <sys/EfiCdefs.h>
+#if defined(LIBM_SCCS) && !defined(lint)
+__RCSID("$NetBSD: s_frexp.c,v 1.12 2002/05/26 22:01:56 wiz Exp $");
+#endif
+
+/*
+ * for non-zero x
+ * x = frexp(arg,&exp);
+ * return a double fp quantity x such that 0.5 <= |x| <1.0
+ * and the corresponding binary exponent "exp". That is
+ * arg = x*2^exp.
+ * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg
+ * with *exp=0.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+static const double
+two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */
+
+double
+frexp(double x, int *eptr)
+{
+ int32_t hx, ix, lx;
+ EXTRACT_WORDS(hx,lx,x);
+ ix = 0x7fffffff&hx;
+ *eptr = 0;
+ if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */
+ if (ix<0x00100000) { /* subnormal */
+ x *= two54;
+ GET_HIGH_WORD(hx,x);
+ ix = hx&0x7fffffff;
+ *eptr = -54;
+ }
+ *eptr += (ix>>20)-1022;
+ hx = (hx&0x800fffff)|0x3fe00000;
+ SET_HIGH_WORD(x,hx);
+ return x;
+}
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