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authorRich Felker <dalias@aerifal.cx>2011-02-12 00:22:29 -0500
committerRich Felker <dalias@aerifal.cx>2011-02-12 00:22:29 -0500
commit0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 (patch)
tree6eaef0d8a720fa3da580de87b647fff796fe80b3 /src/math/s_rintf.c
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initial check-in, version 0.5.0 v0.5.0
Diffstat (limited to 'src/math/s_rintf.c')
-rw-r--r--src/math/s_rintf.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/src/math/s_rintf.c b/src/math/s_rintf.c
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+/* s_rintf.c -- float version of s_rint.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
+TWO23[2]={
+  8.3886080000e+06, /* 0x4b000000 */
+ -8.3886080000e+06, /* 0xcb000000 */
+};
+
+float
+rintf(float x)
+{
+        int32_t i0,j0,sx;
+        volatile float w,t;     /* volatile works around gcc bug */
+        GET_FLOAT_WORD(i0,x);
+        sx = (i0>>31)&1;
+        j0 = ((i0>>23)&0xff)-0x7f;
+        if(j0<23) {
+            if(j0<0) {
+                if((i0&0x7fffffff)==0) return x;
+                w = TWO23[sx]+x;
+                t =  w-TWO23[sx];
+                return t;
+            }
+            w = TWO23[sx]+x;
+            return w-TWO23[sx];
+        }
+        if(j0==0x80) return x+x;        /* inf or NaN */
+        else return x;                  /* x is integral */
+}