* libtommath/bn_mp_sqrt.c (bn_mp_sqrt): Handle the case where

* tests/expr.test (expr-47.13):         a number's square root
is between n<<DIGIT_BIT and n<<DIGIT_BIT+1. [Bug 2143288]
Thanks to Malcolm Boffey (malcolm.boffey@virgin.net) for
the patch.

1 files changed, 22 insertions, 1 deletions

diff --git a/tests/expr.test b/tests/expr.test
index d0aaadb..e51e4c1 100644
--- a/tests/expr.test
+++ b/tests/expr.test
@@ -10,7 +10,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: expr.test,v 1.72 2008/03/10 16:18:55 dgp Exp $
+# RCS: @(#) $Id: expr.test,v 1.73 2008/10/05 21:27:07 kennykb Exp $
 
 if {[lsearch [namespace children] ::tcltest] == -1} {
     package require tcltest 2.1
@@ -6770,6 +6770,7 @@ test expr-47.11 {isqrt of zero} {
 
 test expr-47.12 {isqrt of various sizes of integer} {
     set faults 0
+    set trouble {}
     for {set i 0} {$faults < 10 && $i <= 1024} {incr i} {
 	set root [expr {1 << $i}]
 	set rm1 [expr {$root - 1}]
@@ -6796,6 +6797,26 @@ test expr-47.12 {isqrt of various sizes of integer} {
     set trouble
 } {}
 
+test expr-47.13 {isqrt and floating point rounding (Bug 2143288)} {
+    set trouble {}
+    set faults 0
+    for {set i 0} {$i < 29 && $faults < 10} {incr i} {
+	for {set j 0} {$j <= $i} {incr j} {
+	    set k [expr {isqrt((1<<56)+(1<<$i)+(1<<$j))}]
+	    if {$k != (1<<28)} {
+		append trouble "i = $i, j = $j, k = $k\n"
+		incr faults
+	    }
+	}
+	set k [expr {isqrt((1<<56)+(1<<29)+(1<<$i))}]
+	if {$k != (1<<28)+1} {
+	    append trouble "i = $i, k = $k\n"
+	    incr faults
+	}
+    }
+    set trouble
+} {}
+
 test expr-48.1 {Bug 1770224} {
     expr {-0x8000000000000001 >> 0x8000000000000000}
 } -1