first commit of the new libm!

[musl] / src / math / acosl.c

diff --git a/src/math/acosl.c b/src/math/acosl.c
new file mode 100644 (file)
index 0000000..21e6c95
--- /dev/null
+++ b/src/math/acosl.c
@@ -0,0 +1,91 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_acosl.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+/*
+ * See comments in acos.c.
+ * Converted to long double by David Schultz <das@FreeBSD.ORG>.
+ */
+
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double acosl(long double x)
+{
+       return acos(x);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+#include "__invtrigl.h"
+
+static const long double
+one = 1.00000000000000000000e+00;
+
+// FIXME
+//#ifdef __i386__
+/* XXX Work around the fact that gcc truncates long double constants on i386 */
+static volatile double
+pi1 = 3.14159265358979311600e+00, /* 0x1.921fb54442d18p+1 */
+pi2 = 1.22514845490862001043e-16; /* 0x1.1a80000000000p-53 */
+#define pi ((long double)pi1 + pi2)
+//#else
+#if 0
+static const long double
+pi = 3.14159265358979323846264338327950280e+00L;
+#endif
+
+long double acosl(long double x)
+{
+       union IEEEl2bits u;
+       long double z, p, q, r, w, s, c, df;
+       int16_t expsign, expt;
+       u.e = x;
+       expsign = u.xbits.expsign;
+       expt = expsign & 0x7fff;
+       if (expt >= BIAS) {        /* |x| >= 1 */
+               if (expt == BIAS &&
+                       ((u.bits.manh & ~LDBL_NBIT) | u.bits.manl) == 0) {
+                       if (expsign > 0)
+                               return 0.0;  /* acos(1) = 0 */
+                       else
+                               return pi + 2.0 * pio2_lo;  /* acos(-1)= pi */
+               }
+               return (x - x) / (x - x);  /* acos(|x|>1) is NaN */
+       }
+       if (expt < BIAS - 1) {     /* |x| < 0.5 */
+               if (expt < ACOS_CONST)
+                       return pio2_hi + pio2_lo;  /* x tiny: acosl=pi/2 */
+               z = x * x;
+               p = P(z);
+               q = Q(z);
+               r = p / q;
+               return pio2_hi - (x - (pio2_lo - x * r));
+       } else if (expsign < 0) {  /* x < -0.5 */
+               z = (one + x) * 0.5;
+               p = P(z);
+               q = Q(z);
+               s = sqrtl(z);
+               r = p / q;
+               w = r * s - pio2_lo;
+               return pi - 2.0 * (s + w);
+       } else {                   /* x > 0.5 */
+               z = (one - x) * 0.5;
+               s = sqrtl(z);
+               u.e = s;
+               u.bits.manl = 0;
+               df = u.e;
+               c = (z - df * df) / (s + df);
+               p = P(z);
+               q = Q(z);
+               r = p / q;
+               w = r * s + c;
+               return 2.0 * (df + w);
+       }
+}
+#endif