package integer;
+our $VERSION = '1.00';
+
=head1 NAME
integer - Perl pragma to compute arithmetic in integer instead of double
=head1 DESCRIPTION
-This tells the compiler that it's okay to use integer operations
+This tells the compiler to use integer operations
from here to the end of the enclosing BLOCK. On many machines,
this doesn't matter a great deal for most computations, but on those
without floating point hardware, it can make a big difference.
+Note that this affects the operations, not the numbers. If you run this
+code
+
+ use integer;
+ $x = 1.5;
+ $y = $x + 1;
+ $z = -1.5;
+
+you'll be left with C<$x == 1.5>, C<$y == 2> and C<$z == -1>. The $z
+case happens because unary C<-> counts as an operation.
+
+Native integer arithmetic (as provided by your C compiler) is used.
+This means that Perl's own semantics for arithmetic operations may
+not be preserved. One common source of trouble is the modulus of
+negative numbers, which Perl does one way, but your hardware may do
+another.
+
+ % perl -le 'print (4 % -3)'
+ -2
+ % perl -Minteger -le 'print (4 % -3)'
+ 1
+
See L<perlmod/Pragmatic Modules>.
=cut
+$integer::hint_bits = 0x1;
+
sub import {
- $^H |= 1;
+ $^H |= $integer::hint_bits;
}
sub unimport {
- $^H &= ~1;
+ $^H &= ~$integer::hint_bits;
}
1;