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Diffstat (limited to 'usr/src/lib/libm/common/m9x/scalbln.c')
-rw-r--r--usr/src/lib/libm/common/m9x/scalbln.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/m9x/scalbln.c b/usr/src/lib/libm/common/m9x/scalbln.c
new file mode 100644
index 0000000000..eb11e56a54
--- /dev/null
+++ b/usr/src/lib/libm/common/m9x/scalbln.c
@@ -0,0 +1,109 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#if defined(ELFOBJ)
+#pragma weak scalbln = __scalbln
+#endif
+
+#include "libm.h"
+#include <float.h> /* DBL_MAX, DBL_MIN */
+
+static const double twom54 = 5.5511151231257827021181583404541015625e-17;
+#if defined(USE_FPSCALE) || defined(__x86)
+static const double two52 = 4503599627370496.0;
+#else
+/*
+ * Normalize non-zero subnormal x and return biased exponent of x in [-51,0]
+ */
+static int
+ilogb_biased(unsigned *px) {
+ int s = 52;
+ unsigned v = px[HIWORD] & ~0x80000000, w = px[LOWORD], t = v;
+
+ if (t)
+ s -= 32;
+ else
+ t = w;
+ if (t & 0xffff0000)
+ s -= 16, t >>= 16;
+ if (t & 0xff00)
+ s -= 8, t >>= 8;
+ if (t & 0xf0)
+ s -= 4, t >>= 4;
+ t <<= 1;
+ s -= (0xffffaa50 >> t) & 0x3;
+ if (s < 32) {
+ v = (v << s) | w >> (32 - s);
+ w <<= s;
+ } else {
+ v = w << (s - 32);
+ w = 0;
+ }
+ px[HIWORD] = (px[HIWORD] & 0x80000000) | v;
+ px[LOWORD] = w;
+ return (1 - s);
+}
+#endif /* defined(USE_FPSCALE) */
+
+double
+scalbln(double x, long n) {
+ int *px = (int *) &x, ix, k;
+
+ ix = px[HIWORD] & ~0x80000000;
+ k = ix >> 20;
+ if (k == 0x7ff)
+#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
+ return ((px[HIWORD] & 0x80000) != 0 ? x : x + x);
+ /* assumes sparc-like QNaN */
+#else
+ return (x + x);
+#endif
+ if ((px[LOWORD] | ix) == 0 || n == 0)
+ return (x);
+ if (k == 0) {
+#if defined(USE_FPSCALE) || defined(__x86)
+ x *= two52;
+ k = ((px[HIWORD] & ~0x80000000) >> 20) - 52;
+#else
+ k = ilogb_biased((unsigned *) px);
+#endif
+ }
+ k += (int) n;
+ if (n > 5000 || k > 0x7fe)
+ return (DBL_MAX * copysign(DBL_MAX, x));
+ if (n < -5000 || k <= -54)
+ return (DBL_MIN * copysign(DBL_MIN, x));
+ if (k > 0) {
+ px[HIWORD] = (px[HIWORD] & ~0x7ff00000) | (k << 20);
+ return (x);
+ }
+ k += 54;
+ px[HIWORD] = (px[HIWORD] & ~0x7ff00000) | (k << 20);
+ return (x * twom54);
+}