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-rw-r--r--newlib/libm/common/s_lrint.c98
1 files changed, 98 insertions, 0 deletions
diff --git a/newlib/libm/common/s_lrint.c b/newlib/libm/common/s_lrint.c
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+++ b/newlib/libm/common/s_lrint.c
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+
+/* @(#)s_lrint.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.
+ * ====================================================
+ */
+
+/*
+ * lrint(x)
+ * Return x rounded to integral value according to the prevailing
+ * rounding mode.
+ * Method:
+ * Using floating addition.
+ * Exception:
+ * Inexact flag raised if x not equal to lrint(x).
+ */
+
+#include "fdlibm.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+static const double
+#else
+static double
+#endif
+
+/* Adding a double, x, to 2^52 will cause the result to be rounded based on
+ the fractional part of x, according to the implementation's current rounding
+ mode. 2^52 is the smallest double that can be represented using all 52 significant
+ digits. */
+TWO52[2]={
+ 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+ -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+};
+
+#ifdef __STDC__
+ long int lrint(double x)
+#else
+ long int lrint(x)
+ double x;
+#endif
+{
+ __int32_t i0,j0,sx;
+ __uint32_t i1;
+ double t;
+ volatile double w;
+ long int result;
+
+ EXTRACT_WORDS(i0,i1,x);
+ sx = (i0>>31)&1;
+ j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
+
+ if(j0 < 20)
+ {
+ if(j0 < -1)
+ return 0;
+ else
+ {
+ w = TWO52[sx] + x;
+ t = w - TWO52[sx];
+ GET_HIGH_WORD(i0, t);
+ j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
+ i0 &= 0x000fffff;
+ i0 |= 0x00100000;
+ result = i0 >> (20 - j0);
+ }
+ }
+ else if (j0 < (8 * sizeof (long int)) - 1)
+ {
+ if (j0 >= 52)
+ result = ((long int) i0 << (j0 - 20)) | (i1 << (j0 - 52));
+ else
+ {
+ w = TWO52[sx] + x;
+ t = w - TWO52[sx];
+ EXTRACT_WORDS (i0, i1, t);
+ j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
+ i0 &= 0x000fffff;
+ i0 |= 0x00100000;
+ result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
+ }
+ }
+ else
+ {
+ return (long int) x;
+ }
+
+ return sx ? -result : result;
+}
+
+#endif /* _DOUBLE_IS_32BITS */