Math::BigInt 1.58 released

Date: Sun, 09 Jun 2002 22:39:35 +0200 (CEST)
Message-Id: <200206092036.g59KaGPZ1308701@tiku.hut.fi>

Subject: [PATCH] RE: Math::BigInt 1.58 released
From: Tels <perl_dummy@bloodgate.com>
Date: Sun, 09 Jun 2002 22:45:51 +0200 (CEST)
Message-Id: <200206092042.g59KgXPZ1223212@tiku.hut.fi>

p4raw-id: //depot/perl@17145

15 files changed, 229 insertions, 104 deletions

diff --git a/lib/Math/BigFloat.pm b/lib/Math/BigFloat.pm
index ea78da5a77..c9624ba196 100644
--- a/lib/Math/BigFloat.pm
+++ b/lib/Math/BigFloat.pm
@@ -12,7 +12,7 @@ package Math::BigFloat;
 #   _p: precision
 #   _f: flags, used to signal MBI not to touch our private parts
 
-$VERSION = '1.32';
+$VERSION = '1.33';
 require 5.005;
 use Exporter;
 use File::Spec;
@@ -1715,7 +1715,6 @@ sub import
       push @a, $_[$i];
       }
     }
-#  print "mbf @a\n";
 
   # let use Math::BigInt lib => 'GMP'; use Math::BigFloat; still work
   my $mbilib = eval { Math::BigInt->config()->{lib} };
@@ -1728,19 +1727,17 @@ sub import
     {
     # MBI not loaded, or with ne "Math::BigInt"
     $lib .= ",$mbilib" if defined $mbilib;
-  
-#  my @parts = split /::/, $MBI;		# Math::BigInt => Math BigInt
-#  my $file = pop @parts; $file .= '.pm';	# BigInt => BigInt.pm
-#  $file = File::Spec->catfile (@parts, $file);
-
+    $lib =~ s/^,//;				# don't leave empty 
     if ($] < 5.006)
       {
       # Perl < 5.6.0 dies with "out of memory!" when eval() and ':constant' is
       # used in the same script, or eval inside import().
       my @parts = split /::/, $MBI;		# Math::BigInt => Math BigInt
       my $file = pop @parts; $file .= '.pm';	# BigInt => BigInt.pm
+      require File::Spec;
       $file = File::Spec->catfile (@parts, $file);
-      eval { require $file; $MBI->import( lib => '$lib', 'objectify' ); }
+      eval { require "$file"; };
+      $MBI->import( lib => $lib, 'objectify' );
       }
     else
       {
diff --git a/lib/Math/BigInt.pm b/lib/Math/BigInt.pm
index a85a474a45..77f3343639 100644
--- a/lib/Math/BigInt.pm
+++ b/lib/Math/BigInt.pm
@@ -18,7 +18,7 @@ package Math::BigInt;
 my $class = "Math::BigInt";
 require 5.005;
 
-$VERSION = '1.57';
+$VERSION = '1.58';
 use Exporter;
 @ISA =       qw( Exporter );
 @EXPORT_OK = qw( objectify _swap bgcd blcm); 
@@ -1381,7 +1381,12 @@ sub bmod
       {
       my $xsign = $x->{sign};
       $x->{sign} = $y->{sign};
-      $x = $y-$x if $xsign ne $y->{sign};	# one of them '-'
+      if ($xsign ne $y->{sign})
+        {
+        my $t = [ @{$x->{value}} ];			# copy $x
+        $x->{value} = [ @{$y->{value}} ];		# copy $y to $x
+        $x->{value} = $CALC->_sub($y->{value},$t,1); 	# $y-$x
+        }
       }
     else
       {
@@ -1398,7 +1403,7 @@ sub bmod
   $x;
   }
 
-sub bmodinv_not_yet_implemented
+sub bmodinv
   {
   # modular inverse.  given a number which is (hopefully) relatively
   # prime to the modulus, calculate its inverse using Euclid's
@@ -1414,8 +1419,14 @@ sub bmodinv_not_yet_implemented
          || $num->is_zero()				# or num == 0
 	 || $num->{sign} !~ /^[+-]$/			# or num NaN, inf, -inf
         );
-#  return $num                        # i.e., NaN or some kind of infinity,
-#      if ($num->{sign} =~ /\w/);
+  return $num                        # i.e., NaN or some kind of infinity,
+      if ($num->{sign} !~ /^[+-]$/);
+
+  if ($CALC->can('_modinv'))
+    {
+    $num->{value} = $CALC->_modinv($mod->{value});
+    return $num;
+    }
 
   # the remaining case, nonpositive case, $num < 0, is addressed below.
 
@@ -1423,24 +1434,27 @@ sub bmodinv_not_yet_implemented
   my ($a, $b) = ($mod->copy(), $num->copy());
 
   # put least residue into $b if $num was negative
-  $b %= $mod if $b->{sign} eq '-';
+  $b->bmod($mod) if $b->{sign} eq '-';
 
-    # Euclid's Algorithm
-    while( ! $b->is_zero()) {
-      ($a, my $q, $b) = ($b, $self->bdiv( $a->copy(), $b));
-      ($u, $u1) = ($u1, $u - $u1 * $q);
+  # Euclid's Algorithm
+  while (!$b->is_zero())
+    {
+    ($a, my $q, $b) = ($b, $a->copy()->bdiv($b));
+    ($u, $u1) = ($u1, $u - $u1 * $q);
     }
 
-    # if the gcd is not 1, then return NaN!  It would be pointless to
-    # have called bgcd first, because we would then be performing the
-    # same Euclidean Algorithm *twice*
-    return $self->bnan() unless $a->is_one();
+  # if the gcd is not 1, then return NaN!  It would be pointless to
+  # have called bgcd first, because we would then be performing the
+  # same Euclidean Algorithm *twice*
+  return $num->bnan() unless $a->is_one();
 
-    $u %= $mod;
-    return $u;
+  $u->bmod($mod);
+  $num->{value} = $u->{value};
+  $num->{sign} = $u->{sign};
+  $num;
   }
 
-sub bmodpow_not_yet_implemented
+sub bmodpow
   {
   # takes a very large number to a very large exponent in a given very
   # large modulus, quickly, thanks to binary exponentation.  supports
@@ -1459,32 +1473,42 @@ sub bmodpow_not_yet_implemented
     # i.e., if it's NaN, +inf, or -inf...
     return $num->bnan();
     }
-  elsif ($exp->{sign} eq '-')
+
+ my $exp1 = $exp->copy();
+ if ($exp->{sign} eq '-')
     {
-    $exp->babs();
+    $exp1->babs();
     $num->bmodinv ($mod);
-    return $num if $num->{sign} !~ /^[+-]/; 	# i.e. if there was no inverse
+    # return $num if $num->{sign} !~ /^[+-]/; 	# see next check
     }
 
-    # check num for valid values
-    return $num->bnan() if $num->{sign} !~ /^[+-]$/;
+  # check num for valid values (also NaN if there was no inverse)
+  return $num->bnan() if $num->{sign} !~ /^[+-]$/;
 
-    # in the trivial case,
-    return $num->bzero() if $mod->is_one();
-    return $num->bone() if $num->is_zero() or $num->is_one();
+  if ($CALC->can('_modpow'))
+    {
+    # $exp and $mod are positive, result is also positive
+    $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
+    return $num;
+    }
 
-    my $acc = $num->copy(); $num->bone();	# keep ref to $num
+  # in the trivial case,
+  return $num->bzero() if $mod->is_one();
+  return $num->bone() if $num->is_zero() or $num->is_one();
 
-      print "$num $acc $exp\n";	
-    while( !$exp->is_zero() ) {
-      if( $exp->is_odd() ) {
-       $num->bmul($acc)->bmod($mod);
+  $num->bmod($mod);		# if $x is large, make it smaller first
+  my $acc = $num->copy(); $num->bone();	# keep ref to $num
+
+  while( !$exp1->is_zero() )
+    {
+    if( $exp1->is_odd() )
+      {
+      $num->bmul($acc)->bmod($mod);
       }
-      $acc->bmul($acc)->bmod($mod);
-      $exp->brsft( 1, 2);      		# remove last (binary) digit
-      print "$num $acc $exp\n";	
+    $acc->bmul($acc)->bmod($mod);
+    $exp1->brsft( 1, 2);      		# remove last (binary) digit
     }
-  return $num;
+  $num;
   }
 
 ###############################################################################
@@ -2277,15 +2301,18 @@ sub import
   $CALC = '';					# signal error
   foreach my $lib (@c)
     {
+    next if ($lib || '') eq '';
     $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
     $lib =~ s/\.pm$//;
     if ($] < 5.006)
       {
       # Perl < 5.6.0 dies with "out of memory!" when eval() and ':constant' is
       # used in the same script, or eval inside import().
-      (my $mod = $lib . '.pm') =~ s!::!/!g;
-      # require does not automatically :: => /, so portability problems arise
-      eval { require $mod; $lib->import( @c ); }
+      my @parts = split /::/, $lib;             # Math::BigInt => Math BigInt
+      my $file = pop @parts; $file .= '.pm';    # BigInt => BigInt.pm
+      require File::Spec;
+      $file = File::Spec->catfile (@parts, $file);
+      eval { require "$file"; $lib->import( @c ); }
       }
     else
       {
@@ -2425,7 +2452,8 @@ sub _split
     $es = $1; $ev = $2;
     # valid mantissa?
     return if $m eq '.' || $m eq '';
-    my ($mi,$mf) = split /\./,$m;
+    my ($mi,$mf,$last) = split /\./,$m;
+    return if defined $last;		# last defined => 1.2.3 or others
     $mi = '0' if !defined $mi;
     $mi .= '0' if $mi =~ /^[\-\+]?$/;
     $mf = '0' if !defined $mf || $mf eq '';
@@ -2609,6 +2637,8 @@ Math::BigInt - Arbitrary size integer math package
 				# return (quo,rem) or quo if scalar
 
   $x->bmod($y);			# modulus (x % y)
+  $x->bmodpow($exp,$mod);	# modular exponentation (($num**$exp) % $mod))
+  $x->bmodinv($mod);		# the inverse of $x in the given modulus $mod
 
   $x->bpow($y);			# power of arguments (x ** y)
   $x->blsft($y);		# left shift
@@ -2932,8 +2962,6 @@ numbers.
 
 =head2 bmodinv
 
-Not yet implemented.
-
   bmodinv($num,$mod);          # modular inverse (no OO style)
 
 Returns the inverse of C<$num> in the given modulus C<$mod>.  'C<NaN>' is
@@ -2942,8 +2970,6 @@ C<bgcd($num, $mod)==1>.
 
 =head2 bmodpow
 
-Not yet implemented.
-
   bmodpow($num,$exp,$mod);     # modular exponentation ($num**$exp % $mod)
 
 Returns the value of C<$num> taken to the power C<$exp> in the modulus
diff --git a/lib/Math/BigInt/Calc.pm b/lib/Math/BigInt/Calc.pm
index a114d09ee8..717361de9e 100644
--- a/lib/Math/BigInt/Calc.pm
+++ b/lib/Math/BigInt/Calc.pm
@@ -8,7 +8,7 @@ require Exporter;
 use vars qw/@ISA $VERSION/;
 @ISA = qw(Exporter);
 
-$VERSION = '0.28';
+$VERSION = '0.29';
 
 # Package to store unsigned big integers in decimal and do math with them
 
@@ -108,6 +108,7 @@ BEGIN
   $e = 5 if $^O =~ /^uts/;	# UTS get's some special treatment
   $e = 5 if $^O =~ /^unicos/;	# unicos is also problematic (6 seems to work
 				# there, but we play safe)
+  $e = 5 if $] < 5.006;		# cap, for older Perls
   $e = 7 if $e > 7;		# cap, for VMS, OS/390 and other 64 bit systems
 				# 8 fails inside random testsuite, so take 7
 
@@ -413,7 +414,7 @@ sub _sub
   #print "case 1 (swap)\n";
   for $i (@$sx)
     {
-    # we can't do an early out if $x is than $y, since we
+    # we can't do an early out if $x is < than $y, since we
     # need to copy the high chunks from $y. Found by Bob Mathews.
     #last unless defined $sy->[$j] || $car;
     $sy->[$j] += $BASE
@@ -1576,7 +1577,10 @@ sub _from_bin
   $x;
   }
 
-sub _modinv
+##############################################################################
+# special modulus functions
+
+sub _modinv1
   {
   # inverse modulus
   }
@@ -1584,6 +1588,43 @@ sub _modinv
 sub _modpow
   {
   # modulus of power ($x ** $y) % $z
+  my ($c,$num,$exp,$mod) = @_;
+
+  # in the trivial case,
+  if (_is_one($c,$mod))
+    {
+    splice @$num,0,1; $num->[0] = 0;
+    return $num;
+    }
+  if ((scalar @$num == 1) && (($num->[0] == 0) || ($num->[0] == 1)))
+    {
+    $num->[0] = 1;
+    return $num;
+    }
+      
+#  $num = _mod($c,$num,$mod);
+
+  my $acc = _copy($c,$num); my $t = _one();
+
+  my $two = _two();
+  my $exp1 = _copy($c,$exp);		# keep arguments
+  while (!_is_zero($c,$exp1))
+    {
+    if (_is_odd($c,$exp1))
+      {
+      _mul($c,$t,$acc);
+      $t = _mod($c,$t,$mod);
+      }
+    _mul($c,$acc,$acc);
+    $acc = _mod($c,$acc,$mod);
+    _div($c,$exp1,$two);
+#    print "exp ",${_str($c,$exp1)},"\n";
+#    print "acc ",${_str($c,$acc)},"\n";
+#    print "num ",${_str($c,$num)},"\n";
+#    print "mod ",${_str($c,$mod)},"\n";
+    }
+  @$num = @$t;
+  $num;
   }
 
 ##############################################################################
diff --git a/lib/Math/BigInt/t/bare_mbf.t b/lib/Math/BigInt/t/bare_mbf.t
index 8b682f99eb..4b9d3bc562 100644
--- a/lib/Math/BigInt/t/bare_mbf.t
+++ b/lib/Math/BigInt/t/bare_mbf.t
@@ -27,7 +27,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 1601;
+  plan tests => 1599;
   }
 
 use Math::BigFloat lib => 'BareCalc';
diff --git a/lib/Math/BigInt/t/bare_mbi.t b/lib/Math/BigInt/t/bare_mbi.t
index 5899dfe03b..9a01dc6fa0 100644
--- a/lib/Math/BigInt/t/bare_mbi.t
+++ b/lib/Math/BigInt/t/bare_mbi.t
@@ -26,7 +26,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2237;
+  plan tests => 2361;
   }
 
 use Math::BigInt lib => 'BareCalc';
diff --git a/lib/Math/BigInt/t/bigfltpm.inc b/lib/Math/BigInt/t/bigfltpm.inc
index d455165d99..3f8ae6ada9 100644
--- a/lib/Math/BigInt/t/bigfltpm.inc
+++ b/lib/Math/BigInt/t/bigfltpm.inc
@@ -384,7 +384,7 @@ abc:123.456:NaN
 #     1.41..7 and not 1.4170 since fallback (bsqrt(9) is '3', not 3.0...0)
 2:0.5:1.41421356237309504880168872420969807857
 #2:0.2:1.148698354997035006798626946777927589444
-6:1.5:14.6969384566990685891837044482353483518
+#6:1.5:14.6969384566990685891837044482353483518
 $div_scale = 20;
 #62.5:12.5:26447206647554886213592.3959144
 $div_scale = 40;
diff --git a/lib/Math/BigInt/t/bigfltpm.t b/lib/Math/BigInt/t/bigfltpm.t
index 871365acff..c5f6bca4c9 100755
--- a/lib/Math/BigInt/t/bigfltpm.t
+++ b/lib/Math/BigInt/t/bigfltpm.t
@@ -26,7 +26,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 1601
+  plan tests => 1599
 	+ 2;		# own tests
   }
 
diff --git a/lib/Math/BigInt/t/bigintpm.inc b/lib/Math/BigInt/t/bigintpm.inc
index 4d74a412ca..795e388236 100644
--- a/lib/Math/BigInt/t/bigintpm.inc
+++ b/lib/Math/BigInt/t/bigintpm.inc
@@ -217,6 +217,7 @@ $try .= '$a = $x->bpow($x);';
 $ans1 = eval $try;
 print "# Tried: '$try'\n" if !ok ($ans1, $class->new(10) ** 10);
 
+###############################################################################
 # test whether op destroys args or not (should better not)
 
 $x = $class->new(3);
@@ -249,6 +250,36 @@ ok ($x, -5);
 $x = $class->new(-5); $y = abs($x);
 ok ($x, -5);
 
+$x = $class->new(8);
+$y = $class->new(-1);
+$z = $class->new(5033);
+my $u = $x->copy()->bmodpow($y,$z);
+ok ($u,4404);
+ok ($y,-1);
+ok ($z,5033);
+
+$x = $class->new(-5); $y = -$x; ok ($x,-5); ok ($y,5);
+$x = $class->new(-5); $y = $x->copy()->bneg(); ok ($x,-5); ok ($y,5);
+
+$x = $class->new(-5); $y = $class->new(3); $x->bmul($y); ok ($x,-15); ok ($y,3);
+$x = $class->new(-5); $y = $class->new(3); $x->badd($y); ok ($x,-2); ok ($y,3);
+$x = $class->new(-5); $y = $class->new(3); $x->bsub($y); ok ($x,-8); ok ($y,3);
+$x = $class->new(-15); $y = $class->new(3); $x->bdiv($y); ok ($x,-5); ok ($y,3);
+$x = $class->new(-5); $y = $class->new(3); $x->bmod($y); ok ($x,1); ok ($y,3);
+
+$x = $class->new(5); $y = $class->new(3); $x->bmul($y); ok ($x,15); ok ($y,3);
+$x = $class->new(5); $y = $class->new(3); $x->badd($y); ok ($x,8); ok ($y,3);
+$x = $class->new(5); $y = $class->new(3); $x->bsub($y); ok ($x,2); ok ($y,3);
+$x = $class->new(15); $y = $class->new(3); $x->bdiv($y); ok ($x,5); ok ($y,3);
+$x = $class->new(5); $y = $class->new(3); $x->bmod($y); ok ($x,2); ok ($y,3);
+
+$x = $class->new(5); $y = $class->new(-3); $x->bmul($y); ok ($x,-15); ok($y,-3);
+$x = $class->new(5); $y = $class->new(-3); $x->badd($y); ok ($x,2); ok($y,-3);
+$x = $class->new(5); $y = $class->new(-3); $x->bsub($y); ok ($x,8); ok($y,-3);
+$x = $class->new(15); $y = $class->new(-3); $x->bdiv($y); ok ($x,-5); ok($y,-3);
+$x = $class->new(5); $y = $class->new(-3); $x->bmod($y); ok ($x,-1); ok($y,-3);
+
+###############################################################################
 # check whether overloading cmp works
 $try = "\$x = $class->new(0);";
 $try .= "\$y = 10;";
@@ -504,6 +535,11 @@ $x = $class->new('-322056000'); ($x,$y) = $x->bdiv('-12882240');
 ok ($y,'0'); is_valid($y);	# $y not '-0'
 
 ###############################################################################
+# bug in $x->bmod($y) if $x < 0 and $y > 0
+
+$x = $class->new('-629'); ok ($x->bmod(5033),4404);
+
+###############################################################################
 # bone/binf etc as plain calls (Lite failed them)
 
 ok ($class->bzero(),0);
@@ -578,6 +614,7 @@ __DATA__
 &%=
 100:3:1
 8:9:8
+-629:5033:4404
 &/=
 100:3:33
 -8:2:-4
@@ -788,6 +825,21 @@ E23:NaN
 1e2e3:NaN
 1e2r:NaN
 1e2.0:NaN
+# bug with two '.' in number beeing valid
+1.2.2:NaN
+1.2.3e1:NaN
+-1.2.3:NaN
+-1.2.3e-4:NaN
+1.2e3.4:NaN
+1.2e-3.4:NaN
+1.2.3.4:NaN
+1.2.t:NaN
+1..2:NaN
+1..2e1:NaN
+1..2e1..1:NaN
+12e1..1:NaN
+..2:NaN
+.-2:NaN
 # leading zeros
 012:12
 0123:123
@@ -1320,42 +1372,43 @@ inf:0:inf
 14:3:4
 # bug in Calc with '99999' vs $BASE-1
 10000000000000000000000000000000000000000000000000000000000000000000000000000000000:10000000375084540248994272022843165711074:999999962491547381984643365663244474111576
-#&bmodinv
-## format: number:modulus:result
-## bmodinv Data errors
-#abc:abc:NaN
-#abc:5:NaN
-#5:abc:NaN
-## bmodinv Expected Results from normal use
-#1:5:1
-#3:5:2
-#-2:5:2
-#324958749843759385732954874325984357439658735983745:2348249874968739:1741662881064902
+&bmodinv
+# format: number:modulus:result
+# bmodinv Data errors
+abc:abc:NaN
+abc:5:NaN
+5:abc:NaN
+# bmodinv Expected Results from normal use
+1:5:1
+3:5:2
+-2:5:2
+8:5033:4404
+324958749843759385732954874325984357439658735983745:2348249874968739:1741662881064902
 ## bmodinv Error cases / useless use of function
-#3:-5:NaN
-#inf:5:NaN
-#&bmodpow
-## format: number:exponent:modulus:result
-## bmodpow Data errors
-#abc:abc:abc:NaN
-#5:abc:abc:NaN
-#abc:5:abc:NaN
-#abc:abc:5:NaN
-#5:5:abc:NaN
-#5:abc:5:NaN
-#abc:5:5:NaN
-## bmodpow Expected results
-#0:0:2:1
-#1:0:2:1
-#0:0:1:0
-#8:7:5032:3840
-#8:-1:5033:4404
-#98436739867439843769485798542749827593285729587325:43698764986460981048259837659386739857456983759328457:6943857329857295827698367:3104744730915914415259518
-## bmodpow Error cases
-#8:8:-5:NaN
-#8:-1:16:NaN
-#inf:5:13:NaN
-#5:inf:13:NaN
+3:-5:NaN
+inf:5:NaN
+&bmodpow
+# format: number:exponent:modulus:result
+# bmodpow Data errors
+abc:abc:abc:NaN
+5:abc:abc:NaN
+abc:5:abc:NaN
+abc:abc:5:NaN
+5:5:abc:NaN
+5:abc:5:NaN
+abc:5:5:NaN
+# bmodpow Expected results
+0:0:2:1
+1:0:2:1
+0:0:1:0
+8:7:5032:3840
+8:-1:5033:4404
+98436739867439843769485798542749827593285729587325:43698764986460981048259837659386739857456983759328457:6943857329857295827698367:3104744730915914415259518
+# bmodpow Error cases
+8:8:-5:NaN
+8:-1:16:NaN
+inf:5:13:NaN
+5:inf:13:NaN
 &bmod
 # inf handling, see table in doc
 0:inf:0
@@ -1457,6 +1510,8 @@ abc:1:abc:NaN
 12345678912345:113:53
 1234567891234567:113:56
 123456789123456789:113:39
+# bug in bmod() not modifying the variable in place
+-629:5033:4404
 &bgcd
 abc:abc:NaN
 abc:+0:NaN
diff --git a/lib/Math/BigInt/t/bigintpm.t b/lib/Math/BigInt/t/bigintpm.t
index c14d4415ef..9bc034106d 100755
--- a/lib/Math/BigInt/t/bigintpm.t
+++ b/lib/Math/BigInt/t/bigintpm.t
@@ -10,7 +10,7 @@ BEGIN
   my $location = $0; $location =~ s/bigintpm.t//;
   unshift @INC, $location; # to locate the testing files
   chdir 't' if -d 't';
-  plan tests => 2237;
+  plan tests => 2361;
   }
 
 use Math::BigInt;
diff --git a/lib/Math/BigInt/t/calling.t b/lib/Math/BigInt/t/calling.t
index 8a0d2bb635..b905385344 100644
--- a/lib/Math/BigInt/t/calling.t
+++ b/lib/Math/BigInt/t/calling.t
@@ -31,6 +31,11 @@ BEGIN
     }
   print "# INC = @INC\n";
   plan tests => 141;
+  if ($] < 5.006)
+    {
+    for (1..141) { skip (1,'Not supported on older Perls'); }
+    exit;
+    }
   }
 
 package Math::BigInt::Test;
diff --git a/lib/Math/BigInt/t/constant.t b/lib/Math/BigInt/t/constant.t
index bdc73c785e..2f14de2a81 100644
--- a/lib/Math/BigInt/t/constant.t
+++ b/lib/Math/BigInt/t/constant.t
@@ -9,6 +9,11 @@ BEGIN
   chdir 't' if -d 't';
   unshift @INC, '../lib'; # for running manually
   plan tests => 7;
+  if ($] < 5.006)
+    {
+    for (1..7) { skip (1,'Not supported on older Perls'); }
+    exit;
+    }
   } 
 
 use Math::BigInt ':constant';
diff --git a/lib/Math/BigInt/t/mbi_rand.t b/lib/Math/BigInt/t/mbi_rand.t
index b6d59ea6f6..11c59ccf0b 100644
--- a/lib/Math/BigInt/t/mbi_rand.t
+++ b/lib/Math/BigInt/t/mbi_rand.t
@@ -7,7 +7,6 @@ my $count;
   
 BEGIN
   {
-  if ($^O eq 'os390') { print "1..0\n"; exit(0) }
   $| = 1;
   unshift @INC, '../lib'; # for running manually
   my $location = $0; $location =~ s/mbi_rand.t//;
@@ -41,12 +40,10 @@ for (my $i = 0; $i < $count; $i++)
   # together digits, we would end up with "1272398823211223" etc.
   while (length($As) < $la) { $As .= int(rand(100)) x int(rand(16)); }
   while (length($Bs) < $lb) { $Bs .= int(rand(100)) x int(rand(16)); }
-  # Strip leading zeros, but don't let As and Bs end up empty.
-  $As =~ s/^0+//; $Bs =~ s/^0+//;
-  $As = '0' if $As eq '';
-  $Bs = '0' if $Bs eq '';
-  $A = $c->new($As); $B = $c->new($Bs);
+  $As =~ s/^0+//; $Bs =~ s/^0+//; 
+  $As = $As || '0'; $Bs = $Bs || '0';
   # print "# As $As\n# Bs $Bs\n";
+  $A = $c->new($As); $B = $c->new($Bs);
   # print "# A $A\n# B $B\n";
   if ($A->is_zero() || $B->is_zero())
     {
@@ -64,4 +61,3 @@ for (my $i = 0; $i < $count; $i++)
    unless ok ($ADB*$A+$two*$AMB-$AMB,$Bs);
   }
 
-
diff --git a/lib/Math/BigInt/t/sub_mbf.t b/lib/Math/BigInt/t/sub_mbf.t
index 69a1ab9158..206fe62e66 100755
--- a/lib/Math/BigInt/t/sub_mbf.t
+++ b/lib/Math/BigInt/t/sub_mbf.t
@@ -26,7 +26,7 @@ BEGIN
     }
   print "# INC = @INC\n"; 
   
-  plan tests => 1601
+  plan tests => 1599
     + 6;	# + our own tests
   }
 
diff --git a/lib/Math/BigInt/t/sub_mbi.t b/lib/Math/BigInt/t/sub_mbi.t
index 95a0dae1dc..dcd8645201 100755
--- a/lib/Math/BigInt/t/sub_mbi.t
+++ b/lib/Math/BigInt/t/sub_mbi.t
@@ -26,8 +26,8 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2237
-    + 5;	# +4 own tests
+  plan tests => 2361
+    + 5;	# +5 own tests
   }
 
 use Math::BigInt::Subclass;
diff --git a/lib/Math/BigInt/t/with_sub.t b/lib/Math/BigInt/t/with_sub.t
index 07aa3c20f8..ad20ed865f 100644
--- a/lib/Math/BigInt/t/with_sub.t
+++ b/lib/Math/BigInt/t/with_sub.t
@@ -28,7 +28,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 1601
+  plan tests => 1599
 	+ 1;
   }