Merged the decimal-branch (revisions 54886 to 58140). Decimal is now
fully updated to the latests Decimal Specification (v1.66) and the
latests test cases (v2.56).

Thanks to Mark Dickinson for all his help during this process.
diff --git a/Lib/test/decimaltestdata/rounding.decTest b/Lib/test/decimaltestdata/rounding.decTest
index f1437a5..d24fbfb 100644
--- a/Lib/test/decimaltestdata/rounding.decTest
+++ b/Lib/test/decimaltestdata/rounding.decTest
@@ -1,6 +1,6 @@
 ------------------------------------------------------------------------
 -- rounding.decTest -- decimal rounding modes testcases               --
--- Copyright (c) IBM Corporation, 1981, 2003.  All rights reserved.   --
+-- Copyright (c) IBM Corporation, 1981, 2007.  All rights reserved.   --
 ------------------------------------------------------------------------
 -- Please see the document "General Decimal Arithmetic Testcases"     --
 -- at http://www2.hursley.ibm.com/decimal for the description of      --
@@ -17,7 +17,7 @@
 --   IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK         --
 --   mfc@uk.ibm.com                                                   --
 ------------------------------------------------------------------------
-version: 2.39
+version: 2.56
 
 -- These tests require that implementations take account of residues in
 -- order to get correct results for some rounding modes.  Rather than
@@ -26,8 +26,11 @@
 -- is rounding of negatives (if the latter works for addition, assume it
 -- works for the others, too).]
 --
--- Underflow Subnormal and overflow behaviours are tested under the individual
--- operators.
+-- Round-for-reround (05UP) is tested as a separate block, mostly for
+-- 'historical' reasons.
+--
+-- Underflow Subnormal and overflow behaviours are tested under the
+-- individual operators.
 
 extended:    1
 precision:   5           -- for easier visual inspection
@@ -980,8 +983,8 @@
 rounding: down
 rovx100  multiply   10    9E+999999999 ->  9.9999E+999999999 Overflow Inexact Rounded
 rovx101  multiply  -10    9E+999999999 -> -9.9999E+999999999 Overflow Inexact Rounded
-rovx102  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded
-rovx104  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded
+rovx102  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
+rovx104  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
 
 rounding: up
 rovx110  multiply   10    9E+999999999 ->  Infinity Overflow Inexact Rounded
@@ -993,31 +996,31 @@
 rovx120  multiply   10    9E+999999999 ->  Infinity Overflow Inexact Rounded
 rovx121  multiply  -10    9E+999999999 -> -9.9999E+999999999 Overflow Inexact Rounded
 rovx122  divide     1E-9  9E+999999999 ->  1E-1000000003 Underflow Subnormal Inexact Rounded
-rovx124  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded
+rovx124  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
 
 rounding: floor
 rovx130  multiply   10    9E+999999999 ->  9.9999E+999999999 Overflow Inexact Rounded
 rovx131  multiply  -10    9E+999999999 -> -Infinity Overflow Inexact Rounded
-rovx132  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded
+rovx132  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
 rovx134  divide    -1E-9  9E+999999999 -> -1E-1000000003 Underflow Subnormal Inexact Rounded
 
 rounding: half_up
 rovx140  multiply   10    9E+999999999 ->  Infinity Overflow Inexact Rounded
 rovx141  multiply  -10    9E+999999999 -> -Infinity Overflow Inexact Rounded
-rovx142  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded
-rovx144  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded
+rovx142  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
+rovx144  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
 
 rounding: half_even
 rovx150  multiply   10    9E+999999999 ->  Infinity Overflow Inexact Rounded
 rovx151  multiply  -10    9E+999999999 -> -Infinity Overflow Inexact Rounded
-rovx152  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded
-rovx154  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded
+rovx152  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
+rovx154  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
 
 rounding: half_down
 rovx160  multiply   10    9E+999999999 ->  Infinity Overflow Inexact Rounded
 rovx161  multiply  -10    9E+999999999 -> -Infinity Overflow Inexact Rounded
-rovx162  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded
-rovx164  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded
+rovx162  divide     1E-9  9E+999999999 ->  0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
+rovx164  divide    -1E-9  9E+999999999 -> -0E-1000000003 Underflow Subnormal Inexact Rounded Clamped
 
 -- check maximum finite value over a range of precisions
 rounding: down
@@ -1077,3 +1080,224 @@
 rmex412 multiply -9.999E+999999999 10 -> -9.99999999E+999999999 Overflow Inexact Rounded
 rmex413 multiply  9.999E+999999999 10 ->  9.99999999E+999999999 Overflow Inexact Rounded
 
+----- Round-for-reround -----
+rounding:    05up
+precision:   5           -- for easier visual inspection
+maxExponent: 999
+minexponent: -999
+
+-- basic rounding; really is just 0 and 5 up
+r05up001 add 12340  0.001     -> 12341 Inexact Rounded
+r05up002 add 12341  0.001     -> 12341 Inexact Rounded
+r05up003 add 12342  0.001     -> 12342 Inexact Rounded
+r05up004 add 12343  0.001     -> 12343 Inexact Rounded
+r05up005 add 12344  0.001     -> 12344 Inexact Rounded
+r05up006 add 12345  0.001     -> 12346 Inexact Rounded
+r05up007 add 12346  0.001     -> 12346 Inexact Rounded
+r05up008 add 12347  0.001     -> 12347 Inexact Rounded
+r05up009 add 12348  0.001     -> 12348 Inexact Rounded
+r05up010 add 12349  0.001     -> 12349 Inexact Rounded
+
+r05up011 add 12340  0.000     -> 12340 Rounded
+r05up012 add 12341  0.000     -> 12341 Rounded
+r05up013 add 12342  0.000     -> 12342 Rounded
+r05up014 add 12343  0.000     -> 12343 Rounded
+r05up015 add 12344  0.000     -> 12344 Rounded
+r05up016 add 12345  0.000     -> 12345 Rounded
+r05up017 add 12346  0.000     -> 12346 Rounded
+r05up018 add 12347  0.000     -> 12347 Rounded
+r05up019 add 12348  0.000     -> 12348 Rounded
+r05up020 add 12349  0.000     -> 12349 Rounded
+
+r05up021 add 12340  0.901     -> 12341 Inexact Rounded
+r05up022 add 12341  0.901     -> 12341 Inexact Rounded
+r05up023 add 12342  0.901     -> 12342 Inexact Rounded
+r05up024 add 12343  0.901     -> 12343 Inexact Rounded
+r05up025 add 12344  0.901     -> 12344 Inexact Rounded
+r05up026 add 12345  0.901     -> 12346 Inexact Rounded
+r05up027 add 12346  0.901     -> 12346 Inexact Rounded
+r05up028 add 12347  0.901     -> 12347 Inexact Rounded
+r05up029 add 12348  0.901     -> 12348 Inexact Rounded
+r05up030 add 12349  0.901     -> 12349 Inexact Rounded
+
+r05up031 add -12340  -0.001     -> -12341 Inexact Rounded
+r05up032 add -12341  -0.001     -> -12341 Inexact Rounded
+r05up033 add -12342  -0.001     -> -12342 Inexact Rounded
+r05up034 add -12343  -0.001     -> -12343 Inexact Rounded
+r05up035 add -12344  -0.001     -> -12344 Inexact Rounded
+r05up036 add -12345  -0.001     -> -12346 Inexact Rounded
+r05up037 add -12346  -0.001     -> -12346 Inexact Rounded
+r05up038 add -12347  -0.001     -> -12347 Inexact Rounded
+r05up039 add -12348  -0.001     -> -12348 Inexact Rounded
+r05up040 add -12349  -0.001     -> -12349 Inexact Rounded
+
+r05up041 add -12340   0.001     -> -12339 Inexact Rounded
+r05up042 add -12341   0.001     -> -12341 Inexact Rounded
+r05up043 add -12342   0.001     -> -12341 Inexact Rounded
+r05up044 add -12343   0.001     -> -12342 Inexact Rounded
+r05up045 add -12344   0.001     -> -12343 Inexact Rounded
+r05up046 add -12345   0.001     -> -12344 Inexact Rounded
+r05up047 add -12346   0.001     -> -12346 Inexact Rounded
+r05up048 add -12347   0.001     -> -12346 Inexact Rounded
+r05up049 add -12348   0.001     -> -12347 Inexact Rounded
+r05up050 add -12349   0.001     -> -12348 Inexact Rounded
+
+-- Addition operators -------------------------------------------------
+-- [The first few of these check negative residue possibilities; these
+-- cases may be implemented as a negative residue in fastpaths]
+
+r0adx100  add 12345 -0.1       -> 12344 Inexact Rounded
+r0adx101  add 12345 -0.01      -> 12344 Inexact Rounded
+r0adx102  add 12345 -0.001     -> 12344 Inexact Rounded
+r0adx103  add 12345 -0.00001   -> 12344 Inexact Rounded
+r0adx104  add 12345 -0.000001  -> 12344 Inexact Rounded
+r0adx105  add 12345 -0.0000001 -> 12344 Inexact Rounded
+r0adx106  add 12345  0         -> 12345
+r0adx107  add 12345  0.0000001 -> 12346 Inexact Rounded
+r0adx108  add 12345  0.000001  -> 12346 Inexact Rounded
+r0adx109  add 12345  0.00001   -> 12346 Inexact Rounded
+r0adx110  add 12345  0.0001    -> 12346 Inexact Rounded
+r0adx111  add 12345  0.001     -> 12346 Inexact Rounded
+r0adx112  add 12345  0.01      -> 12346 Inexact Rounded
+r0adx113  add 12345  0.1       -> 12346 Inexact Rounded
+
+r0adx115  add 12346  0.49999   -> 12346 Inexact Rounded
+r0adx116  add 12346  0.5       -> 12346 Inexact Rounded
+r0adx117  add 12346  0.50001   -> 12346 Inexact Rounded
+
+r0adx120  add 12345  0.4       -> 12346 Inexact Rounded
+r0adx121  add 12345  0.49      -> 12346 Inexact Rounded
+r0adx122  add 12345  0.499     -> 12346 Inexact Rounded
+r0adx123  add 12345  0.49999   -> 12346 Inexact Rounded
+r0adx124  add 12345  0.5       -> 12346 Inexact Rounded
+r0adx125  add 12345  0.50001   -> 12346 Inexact Rounded
+r0adx126  add 12345  0.5001    -> 12346 Inexact Rounded
+r0adx127  add 12345  0.501     -> 12346 Inexact Rounded
+r0adx128  add 12345  0.51      -> 12346 Inexact Rounded
+r0adx129  add 12345  0.6       -> 12346 Inexact Rounded
+
+-- negatives...
+
+r0sux100  add -12345 -0.1       -> -12346 Inexact Rounded
+r0sux101  add -12345 -0.01      -> -12346 Inexact Rounded
+r0sux102  add -12345 -0.001     -> -12346 Inexact Rounded
+r0sux103  add -12345 -0.00001   -> -12346 Inexact Rounded
+r0sux104  add -12345 -0.000001  -> -12346 Inexact Rounded
+r0sux105  add -12345 -0.0000001 -> -12346 Inexact Rounded
+r0sux106  add -12345  0         -> -12345
+r0sux107  add -12345  0.0000001 -> -12344 Inexact Rounded
+r0sux108  add -12345  0.000001  -> -12344 Inexact Rounded
+r0sux109  add -12345  0.00001   -> -12344 Inexact Rounded
+r0sux110  add -12345  0.0001    -> -12344 Inexact Rounded
+r0sux111  add -12345  0.001     -> -12344 Inexact Rounded
+r0sux112  add -12345  0.01      -> -12344 Inexact Rounded
+r0sux113  add -12345  0.1       -> -12344 Inexact Rounded
+
+r0sux115  add -12346  0.49999   -> -12346 Inexact Rounded
+r0sux116  add -12346  0.5       -> -12346 Inexact Rounded
+r0sux117  add -12346  0.50001   -> -12346 Inexact Rounded
+
+r0sux120  add -12345  0.4       -> -12344 Inexact Rounded
+r0sux121  add -12345  0.49      -> -12344 Inexact Rounded
+r0sux122  add -12345  0.499     -> -12344 Inexact Rounded
+r0sux123  add -12345  0.49999   -> -12344 Inexact Rounded
+r0sux124  add -12345  0.5       -> -12344 Inexact Rounded
+r0sux125  add -12345  0.50001   -> -12344 Inexact Rounded
+r0sux126  add -12345  0.5001    -> -12344 Inexact Rounded
+r0sux127  add -12345  0.501     -> -12344 Inexact Rounded
+r0sux128  add -12345  0.51      -> -12344 Inexact Rounded
+r0sux129  add -12345  0.6       -> -12344 Inexact Rounded
+
+-- Check cancellation subtractions
+-- (The IEEE 854 'curious rule' in $6.3)
+
+r0zex001  add  0    0    ->  0
+r0zex002  add  0   -0    ->  0
+r0zex003  add -0    0    ->  0
+r0zex004  add -0   -0    -> -0
+r0zex005  add  1   -1    ->  0
+r0zex006  add -1    1    ->  0
+r0zex007  add  1.5 -1.5  ->  0.0
+r0zex008  add -1.5  1.5  ->  0.0
+r0zex009  add  2   -2    ->  0
+r0zex010  add -2    2    ->  0
+
+
+-- Division operators -------------------------------------------------
+
+r0dvx101  divide 12345  1         ->  12345
+r0dvx102  divide 12345  1.0001    ->  12343 Inexact Rounded
+r0dvx103  divide 12345  1.001     ->  12332 Inexact Rounded
+r0dvx104  divide 12345  1.01      ->  12222 Inexact Rounded
+r0dvx105  divide 12345  1.1       ->  11222 Inexact Rounded
+r0dvx106  divide 12355  4         ->   3088.7 Inexact Rounded
+r0dvx107  divide 12345  4         ->   3086.2 Inexact Rounded
+r0dvx108  divide 12355  4.0001    ->   3088.6 Inexact Rounded
+r0dvx109  divide 12345  4.0001    ->   3086.1 Inexact Rounded
+r0dvx110  divide 12345  4.9       ->   2519.3 Inexact Rounded
+r0dvx111  divide 12345  4.99      ->   2473.9 Inexact Rounded
+r0dvx112  divide 12345  4.999     ->   2469.4 Inexact Rounded
+r0dvx113  divide 12345  4.9999    ->   2469.1 Inexact Rounded
+r0dvx114  divide 12345  5         ->   2469
+r0dvx115  divide 12345  5.0001    ->  2468.9 Inexact Rounded
+r0dvx116  divide 12345  5.001     ->  2468.6 Inexact Rounded
+r0dvx117  divide 12345  5.01      ->  2464.1 Inexact Rounded
+r0dvx118  divide 12345  5.1       ->  2420.6 Inexact Rounded
+
+-- [divideInteger and remainder unaffected]
+
+-- Multiplication operator --------------------------------------------
+
+r0mux101  multiply 12345  1         ->  12345
+r0mux102  multiply 12345  1.0001    ->  12346 Inexact Rounded
+r0mux103  multiply 12345  1.001     ->  12357 Inexact Rounded
+r0mux104  multiply 12345  1.01      ->  12468 Inexact Rounded
+r0mux105  multiply 12345  1.1       ->  13579 Inexact Rounded
+r0mux106  multiply 12345  4         ->  49380
+r0mux107  multiply 12345  4.0001    ->  49381 Inexact Rounded
+r0mux108  multiply 12345  4.9       ->  60491 Inexact Rounded
+r0mux109  multiply 12345  4.99      ->  61601 Inexact Rounded
+r0mux110  multiply 12345  4.999     ->  61712 Inexact Rounded
+r0mux111  multiply 12345  4.9999    ->  61723 Inexact Rounded
+r0mux112  multiply 12345  5         ->  61725
+r0mux113  multiply 12345  5.0001    ->  61726 Inexact Rounded
+r0mux114  multiply 12345  5.001     ->  61737 Inexact Rounded
+r0mux115  multiply 12345  5.01      ->  61848 Inexact Rounded
+r0mux116  multiply 12345  12        ->  1.4814E+5 Rounded
+r0mux117  multiply 12345  13        ->  1.6048E+5 Inexact Rounded
+r0mux118  multiply 12355  12        ->  1.4826E+5 Rounded
+r0mux119  multiply 12355  13        ->  1.6061E+5 Inexact Rounded
+
+
+-- Power operator -----------------------------------------------------
+
+r0pox101  power 12345  -5        ->  3.4877E-21 Inexact Rounded
+r0pox102  power 12345  -4        ->  4.3056E-17 Inexact Rounded
+r0pox103  power 12345  -3        ->  5.3152E-13 Inexact Rounded
+r0pox104  power 12345  -2        ->  6.5617E-9 Inexact Rounded
+r0pox105  power 12345  -1        ->  0.000081004 Inexact Rounded
+r0pox106  power 12345  0         ->  1
+r0pox107  power 12345  1         ->  12345
+r0pox108  power 12345  2         ->  1.5239E+8 Inexact Rounded
+r0pox109  power 12345  3         ->  1.8813E+12 Inexact Rounded
+r0pox110  power 12345  4         ->  2.3226E+16 Inexact Rounded
+r0pox111  power 12345  5         ->  2.8671E+20 Inexact Rounded
+r0pox112  power   415  2         ->  1.7222E+5 Inexact Rounded
+r0pox113  power    75  3         ->  4.2187E+5 Inexact Rounded
+
+
+-- Underflow Subnormal and overflow values vary with rounding mode and sign
+maxexponent: 999999999
+minexponent: -999999999
+-- [round down gives Nmax on first two and .0E... on the next two]
+r0ovx100  multiply   10    9E+999999999 ->  9.9999E+999999999 Overflow Inexact Rounded
+r0ovx101  multiply  -10    9E+999999999 -> -9.9999E+999999999 Overflow Inexact Rounded
+r0ovx102  divide     1E-9  9E+999999999 ->  1E-1000000003 Underflow Subnormal Inexact Rounded
+r0ovx104  divide    -1E-9  9E+999999999 -> -1E-1000000003 Underflow Subnormal Inexact Rounded
+
+-- reprise rounding mode effect (using multiplies so precision directive used)
+precision: 9
+maxexponent: 999999999
+r0mex412 multiply -9.999E+999999999 10 -> -9.99999999E+999999999 Overflow Inexact Rounded
+r0mex413 multiply  9.999E+999999999 10 ->  9.99999999E+999999999 Overflow Inexact Rounded
+