first commit of the new libm!

[musl] / src / math / rintf.c

diff --git a/src/math/rintf.c b/src/math/rintf.c
new file mode 100644 (file)
index 0000000..e8d4496
--- /dev/null
+++ b/src/math/rintf.c
@@ -0,0 +1,48 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_rintf.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 "libm.h"
+
+static const float
+TWO23[2] = {
+  8.3886080000e+06, /* 0x4b000000 */
+ -8.3886080000e+06, /* 0xcb000000 */
+};
+
+float rintf(float x)
+{
+       int32_t i0,j0,sx;
+       float w,t;
+
+       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;
+                       STRICT_ASSIGN(float, w, TWO23[sx] + x);
+                       t = w - TWO23[sx];
+                       GET_FLOAT_WORD(i0, t);
+                       SET_FLOAT_WORD(t, (i0&0x7fffffff)|(sx<<31));
+                       return t;
+               }
+               STRICT_ASSIGN(float, w, TWO23[sx] + x);
+               return w - TWO23[sx];
+       }
+       if (j0 == 0x80)
+               return x+x;  /* inf or NaN */
+       return x;            /* x is integral */
+}