PowerPC floating point little-endian [3 of 15]

http://sourceware.org/ml/libc-alpha/2013-08/msg00083.html

Further replacement of ieee854 macros and unions.  These files also
have some optimisations for comparison against 0.0L, infinity and nan.
Since the ABI specifies that the high double of an IBM long double
pair is the value rounded to double, a high double of 0.0 means the
low double must also be 0.0.  The ABI also says that infinity and
nan are encoded in the high double, with the low double unspecified.
This means that tests for 0.0L, +/-Infinity and +/-NaN need only check
the high double.

	* sysdeps/ieee754/ldbl-128ibm/e_atan2l.c (__ieee754_atan2l): Rewrite
	all uses of ieee854 long double macros and unions.  Simplify tests
	for long doubles that are fully specified by the high double.
	* sysdeps/ieee754/ldbl-128ibm/e_gammal_r.c (__ieee754_gammal_r):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c (__ieee754_ilogbl): Likewise.
	Remove dead code too.
	* sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Likewise.
	(__ieee754_ynl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_log10l.c (__ieee754_log10l): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_logl.c (__ieee754_logl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Likewise.
	Remove dead code too.
	* sysdeps/ieee754/ldbl-128ibm/k_tanl.c (__kernel_tanl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_expm1l.c (__expm1l): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_frexpl.c (__frexpl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_isinf_nsl.c (__isinf_nsl): Likewise.
	Simplify.
	* sysdeps/ieee754/ldbl-128ibm/s_isinfl.c (___isinfl): Likewise.
	Simplify.
	* sysdeps/ieee754/ldbl-128ibm/s_log1pl.c (__log1pl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_modfl.c (__modfl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c (__nextafterl): Likewise.
	Comment on variable precision.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c (__nexttoward): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c (__nexttowardf):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_remquol.c (__remquol): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c (__scalblnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_scalbnl.c (__scalbnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_tanhl.c (__tanhl): Likewise.
	* sysdeps/powerpc/fpu/libm-test-ulps: Adjust tan_towardzero ulps.

1 files changed, 15 insertions, 17 deletions

diff --git a/sysdeps/ieee754/ldbl-128ibm/e_logl.c b/sysdeps/ieee754/ldbl-128ibm/e_logl.c
index 15b5edfab3..b7db2b9784 100644
--- a/sysdeps/ieee754/ldbl-128ibm/e_logl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/e_logl.c
@@ -188,18 +188,20 @@ static const long double
 long double
 __ieee754_logl(long double x)
 {
-  long double z, y, w;
-  ieee854_long_double_shape_type u, t;
+  long double z, y, w, t;
   unsigned int m;
   int k, e;
+  double xhi;
+  uint32_t hx, lx;
 
-  u.value = x;
-  m = u.parts32.w0;
+  xhi = ldbl_high (x);
+  EXTRACT_WORDS (hx, lx, xhi);
+  m = hx;
 
   /* Check for IEEE special cases.  */
   k = m & 0x7fffffff;
   /* log(0) = -infinity. */
-  if ((k | u.parts32.w1 | (u.parts32.w2 & 0x7fffffff) | u.parts32.w3) == 0)
+  if ((k | lx) == 0)
     {
       return -0.5L / ZERO;
     }
@@ -219,7 +221,7 @@ __ieee754_logl(long double x)
     {
       z = x - 1.0L;
       k = 64;
-      t.value  = 1.0L;
+      t = 1.0L;
       e = 0;
     }
   else
@@ -236,10 +238,8 @@ __ieee754_logl(long double x)
 	  k = (m - 0xff000) >> 13;
 	  /* t is the argument 0.5 + (k+26)/128
 	     of the nearest item to u in the lookup table.  */
-	  t.parts32.w0 = 0x3ff00000 + (k << 13);
-	  t.parts32.w1 = 0;
-	  t.parts32.w2 = 0;
-	  t.parts32.w3 = 0;
+	  INSERT_WORDS (xhi, 0x3ff00000 + (k << 13), 0);
+	  t = xhi;
 	  w0 += 0x100000;
 	  e -= 1;
 	  k += 64;
@@ -247,17 +247,15 @@ __ieee754_logl(long double x)
       else
 	{
 	  k = (m - 0xfe000) >> 14;
-	  t.parts32.w0 = 0x3fe00000 + (k << 14);
-	  t.parts32.w1 = 0;
-	  t.parts32.w2 = 0;
-	  t.parts32.w3 = 0;
+	  INSERT_WORDS (xhi, 0x3fe00000 + (k << 14), 0);
+	  t = xhi;
 	}
-      u.value = __scalbnl (u.value, ((int) ((w0 - u.parts32.w0) * 2)) >> 21);
+      x = __scalbnl (x, ((int) ((w0 - hx) * 2)) >> 21);
       /* log(u) = log( t u/t ) = log(t) + log(u/t)
 	 log(t) is tabulated in the lookup table.
 	 Express log(u/t) = log(1+z),  where z = u/t - 1 = (u-t)/t.
 	 cf. Cody & Waite. */
-      z = (u.value - t.value) / t.value;
+      z = (x - t) / t;
     }
   /* Series expansion of log(1+z).  */
   w = z * z;
@@ -284,7 +282,7 @@ __ieee754_logl(long double x)
   y += e * ln2b;  /* Base 2 exponent offset times ln(2).  */
   y += z;
   y += logtbl[k-26]; /* log(t) - (t-1) */
-  y += (t.value - 1.0L);
+  y += (t - 1.0L);
   y += e * ln2a;
   return y;
 }