# commit 62a728aeff93507ce5975f245a5f1d2046fb4503

# Author: Alan Modra <amodra@gmail.com>

# Date:   Sat Aug 17 18:27:19 2013 +0930

# 

#     PowerPC floating point little-endian [6 of 15]

#     http://sourceware.org/ml/libc-alpha/2013-07/msg00197.html

#     

#     A rewrite to make this code correct for little-endian.

#     

#         * sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c (mynumber): Replace

#         union 32-bit int array member with 64-bit int array.

#         (t515, tm256): Double rather than long double.

#         (__ieee754_sqrtl): Rewrite using 64-bit arithmetic.

#

diff -urN glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c

--- glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c	2014-05-27 22:20:12.000000000 -0500

+++ glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c	2014-05-27 22:21:39.000000000 -0500

@@ -34,15 +34,13 @@

 #include <math_private.h>

-typedef unsigned int int4;

-typedef union {int4 i[4]; long double x; double d[2]; } mynumber;

+typedef union {int64_t i[2]; long double x; double d[2]; } mynumber;

-static const  mynumber

-  t512 = {{0x5ff00000, 0x00000000, 0x00000000, 0x00000000 }},  /* 2^512  */

-  tm256 = {{0x2ff00000, 0x00000000, 0x00000000, 0x00000000 }};  /* 2^-256 */

 static const double

-two54 = 1.80143985094819840000e+16, /* 0x4350000000000000 */

-twom54 = 5.55111512312578270212e-17; /* 0x3C90000000000000 */

+  t512 = 0x1p512,

+  tm256 = 0x1p-256,

+  two54 = 0x1p54,	/* 0x4350000000000000 */

+  twom54 = 0x1p-54;	/* 0x3C90000000000000 */

 /*********************************************************************/

 /* An ultimate sqrt routine. Given an IEEE double machine number x   */

@@ -54,56 +52,53 @@

   static const long double big = 134217728.0, big1 = 134217729.0;

   long double t,s,i;

   mynumber a,c;

-  int4 k, l, m;

-  int n;

+  uint64_t k, l;

+  int64_t m, n;

   double d;

   a.x=x;

-  k=a.i[0] & 0x7fffffff;

+  k=a.i[0] & INT64_C(0x7fffffffffffffff);

   /*----------------- 2^-1022  <= | x |< 2^1024  -----------------*/

-  if (k>0x000fffff && k<0x7ff00000) {

+  if (k>INT64_C(0x000fffff00000000) && k

     if (x < 0) return (big1-big1)/(big-big);

-    l = (k&0x001fffff)|0x3fe00000;

-    if (((a.i[2] & 0x7fffffff) | a.i[3]) != 0) {

-      n = (int) ((l - k) * 2) >> 21;

-      m = (a.i[2] >> 20) & 0x7ff;

+    l = (k&INT64_C(0x001fffffffffffff))|INT64_C(0x3fe0000000000000);

+    if ((a.i[1] & INT64_C(0x7fffffffffffffff)) != 0) {

+      n = (int64_t) ((l - k) * 2) >> 53;

+      m = (a.i[1] >> 52) & 0x7ff;

       if (m == 0) {

 	a.d[1] *= two54;

-	m = ((a.i[2] >> 20) & 0x7ff) - 54;

+	m = ((a.i[1] >> 52) & 0x7ff) - 54;

       }

       m += n;

-      if ((int) m > 0)

-	a.i[2] = (a.i[2] & 0x800fffff) | (m << 20);

-      else if ((int) m <= -54) {

-	a.i[2] &= 0x80000000;

-	a.i[3] = 0;

+      if (m > 0)

+	a.i[1] = (a.i[1] & INT64_C(0x800fffffffffffff)) | (m << 52);

+      else if (m <= -54) {

+	a.i[1] &= INT64_C(0x8000000000000000);

       } else {

 	m += 54;

-	a.i[2] = (a.i[2] & 0x800fffff) | (m << 20);

+	a.i[1] = (a.i[1] & INT64_C(0x800fffffffffffff)) | (m << 52);

 	a.d[1] *= twom54;

       }

     }

     a.i[0] = l;

     s = a.x;

     d = __ieee754_sqrt (a.d[0]);

-    c.i[0] = 0x20000000+((k&0x7fe00000)>>1);

+    c.i[0] = INT64_C(0x2000000000000000)+((k&INT64_C(0x7fe0000000000000))>>1);

     c.i[1] = 0;

-    c.i[2] = 0;

-    c.i[3] = 0;

     i = d;

     t = 0.5L * (i + s / i);

     i = 0.5L * (t + s / t);

     return c.x * i;

   }

   else {

-    if (k>=0x7ff00000) {

-      if (a.i[0] == 0xfff00000 && a.i[1] == 0)

+    if (k>=INT64_C(0x7ff0000000000000)) {

+      if (a.i[0] == INT64_C(0xfff0000000000000))

 	return (big1-big1)/(big-big); /* sqrt (-Inf) = NaN.  */

       return x; /* sqrt (NaN) = NaN, sqrt (+Inf) = +Inf.  */

     }

     if (x == 0) return x;

     if (x < 0) return (big1-big1)/(big-big);

-    return tm256.x*__ieee754_sqrtl(x*t512.x);

+    return tm256*__ieee754_sqrtl(x*t512);

   }

 }

 strong_alias (__ieee754_sqrtl, __sqrtl_finite)