Imported Upstream version 1.4upstream/1.4

1 files changed, 0 insertions, 143 deletions

diff --git a/src/pkg/math/sqrt.go b/src/pkg/math/sqrt.go
deleted file mode 100644
index 1bd4437f1..000000000
--- a/src/pkg/math/sqrt.go
+++ /dev/null
@@ -1,143 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package math
-
-// The original C code and the long comment below are
-// from FreeBSD's /usr/src/lib/msun/src/e_sqrt.c and
-// came with this notice.  The go code is a simplified
-// version of the original C.
-//
-// ====================================================
-// 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.
-// ====================================================
-//
-// __ieee754_sqrt(x)
-// Return correctly rounded sqrt.
-//           -----------------------------------------
-//           | Use the hardware sqrt if you have one |
-//           -----------------------------------------
-// Method:
-//   Bit by bit method using integer arithmetic. (Slow, but portable)
-//   1. Normalization
-//      Scale x to y in [1,4) with even powers of 2:
-//      find an integer k such that  1 <= (y=x*2**(2k)) < 4, then
-//              sqrt(x) = 2**k * sqrt(y)
-//   2. Bit by bit computation
-//      Let q  = sqrt(y) truncated to i bit after binary point (q = 1),
-//           i                                                   0
-//                                     i+1         2
-//          s  = 2*q , and      y  =  2   * ( y - q  ).          (1)
-//           i      i            i                 i
-//
-//      To compute q    from q , one checks whether
-//                  i+1       i
-//
-//                            -(i+1) 2
-//                      (q + 2      )  <= y.                     (2)
-//                        i
-//                                                            -(i+1)
-//      If (2) is false, then q   = q ; otherwise q   = q  + 2      .
-//                             i+1   i             i+1   i
-//
-//      With some algebraic manipulation, it is not difficult to see
-//      that (2) is equivalent to
-//                             -(i+1)
-//                      s  +  2       <= y                       (3)
-//                       i                i
-//
-//      The advantage of (3) is that s  and y  can be computed by
-//                                    i      i
-//      the following recurrence formula:
-//          if (3) is false
-//
-//          s     =  s  ,       y    = y   ;                     (4)
-//           i+1      i          i+1    i
-//
-//      otherwise,
-//                         -i                      -(i+1)
-//          s     =  s  + 2  ,  y    = y  -  s  - 2              (5)
-//           i+1      i          i+1    i     i
-//
-//      One may easily use induction to prove (4) and (5).
-//      Note. Since the left hand side of (3) contain only i+2 bits,
-//            it does not necessary to do a full (53-bit) comparison
-//            in (3).
-//   3. Final rounding
-//      After generating the 53 bits result, we compute one more bit.
-//      Together with the remainder, we can decide whether the
-//      result is exact, bigger than 1/2ulp, or less than 1/2ulp
-//      (it will never equal to 1/2ulp).
-//      The rounding mode can be detected by checking whether
-//      huge + tiny is equal to huge, and whether huge - tiny is
-//      equal to huge for some floating point number "huge" and "tiny".
-//
-//
-// Notes:  Rounding mode detection omitted.  The constants "mask", "shift",
-// and "bias" are found in src/pkg/math/bits.go
-
-// Sqrt returns the square root of x.
-//
-// Special cases are:
-//	Sqrt(+Inf) = +Inf
-//	Sqrt(±0) = ±0
-//	Sqrt(x < 0) = NaN
-//	Sqrt(NaN) = NaN
-func Sqrt(x float64) float64
-
-func sqrt(x float64) float64 {
-	// special cases
-	switch {
-	case x == 0 || IsNaN(x) || IsInf(x, 1):
-		return x
-	case x < 0:
-		return NaN()
-	}
-	ix := Float64bits(x)
-	// normalize x
-	exp := int((ix >> shift) & mask)
-	if exp == 0 { // subnormal x
-		for ix&1<<shift == 0 {
-			ix <<= 1
-			exp--
-		}
-		exp++
-	}
-	exp -= bias // unbias exponent
-	ix &^= mask << shift
-	ix |= 1 << shift
-	if exp&1 == 1 { // odd exp, double x to make it even
-		ix <<= 1
-	}
-	exp >>= 1 // exp = exp/2, exponent of square root
-	// generate sqrt(x) bit by bit
-	ix <<= 1
-	var q, s uint64               // q = sqrt(x)
-	r := uint64(1 << (shift + 1)) // r = moving bit from MSB to LSB
-	for r != 0 {
-		t := s + r
-		if t <= ix {
-			s = t + r
-			ix -= t
-			q += r
-		}
-		ix <<= 1
-		r >>= 1
-	}
-	// final rounding
-	if ix != 0 { // remainder, result not exact
-		q += q & 1 // round according to extra bit
-	}
-	ix = q>>1 + uint64(exp-1+bias)<<shift // significand + biased exponent
-	return Float64frombits(ix)
-}
-
-func sqrtC(f float64, r *float64) {
-	*r = sqrt(f)
-}