Profile: /opt/wise/lib/perl5/5.10.0/integer.pm

File	/opt/wise/lib/perl5/5.10.0/integer.pm
Statements Executed	5
Total Time	1.2e-05 seconds

Subroutines — ordered by exclusive time
Calls	P	F	Exclusive Time	Inclusive Time	Subroutine
2	2	2	1.8e-5	1.8e-5	integer::	import
0	0	0	0	0	integer::	unimport

Line	Stmts.	Exclusive Time	Avg.	Code
1				package integer;
2
3	1	1.0e-6	1.0e-6	our $VERSION = '1.00';
4
5				=head1 NAME
6
7				integer - Perl pragma to use integer arithmetic instead of floating point
8
9				=head1 SYNOPSIS
10
11				use integer;
12				$x = 10/3;
13				# $x is now 3, not 3.33333333333333333
14
15				=head1 DESCRIPTION
16
17				This tells the compiler to use integer operations from here to the end
18				of the enclosing BLOCK. On many machines, this doesn't matter a great
19				deal for most computations, but on those without floating point
20				hardware, it can make a big difference in performance.
21
22				Note that this only affects how most of the arithmetic and relational
23				B<operators> handle their operands and results, and B<not> how all
24				numbers everywhere are treated. Specifically, C<use integer;> has the
25				effect that before computing the results of the arithmetic operators
26				(+, -, , /, %, +=, -=, =, /=, %=, and unary minus), the comparison
27				operators (<, <=, >, >=, ==, !=, <=>), and the bitwise operators (\|, &,
28				^, <<, >>, \|=, &=, ^=, <<=, >>=), the operands have their fractional
29				portions truncated (or floored), and the result will have its
30				fractional portion truncated as well. In addition, the range of
31				operands and results is restricted to that of familiar two's complement
32				integers, i.e., -(231) .. (231-1) on 32-bit architectures, and
33				-(263) .. (263-1) on 64-bit architectures. For example, this code
34
35				use integer;
36				$x = 5.8;
37				$y = 2.5;
38				$z = 2.7;
39				$a = 2**31 - 1; # Largest positive integer on 32-bit machines
40				$, = ", ";
41				print $x, -$x, $x + $y, $x - $y, $x / $y, $x * $y, $y == $z, $a, $a + 1;
42
43				will print: 5.8, -5, 7, 3, 2, 10, 1, 2147483647, -2147483648
44
45				Note that $x is still printed as having its true non-integer value of
46				5.8 since it wasn't operated on. And note too the wrap-around from the
47				largest positive integer to the largest negative one. Also, arguments
48				passed to functions and the values returned by them are B<not> affected
49				by C<use integer;>. E.g.,
50
51				srand(1.5);
52				$, = ", ";
53				print sin(.5), cos(.5), atan2(1,2), sqrt(2), rand(10);
54
55				will give the same result with or without C<use integer;> The power
56				operator C<> is also not affected, so that 2 .5 is always the
57				square root of 2. Now, it so happens that the pre- and post- increment
58				and decrement operators, ++ and --, are not affected by C<use integer;>
59				either. Some may rightly consider this to be a bug -- but at least it's
60				a long-standing one.
61
62				Finally, C<use integer;> also has an additional affect on the bitwise
63				operators. Normally, the operands and results are treated as
64				B<unsigned> integers, but with C<use integer;> the operands and results
65				are B<signed>. This means, among other things, that ~0 is -1, and -2 &
66				-5 is -6.
67
68				Internally, native integer arithmetic (as provided by your C compiler)
69				is used. This means that Perl's own semantics for arithmetic
70				operations may not be preserved. One common source of trouble is the
71				modulus of negative numbers, which Perl does one way, but your hardware
72				may do another.
73
74				% perl -le 'print (4 % -3)'
75				-2
76				% perl -Minteger -le 'print (4 % -3)'
77				1
78
79				See L<perlmodlib/"Pragmatic Modules">, L<perlop/"Integer Arithmetic">
80
81				=cut
82
83	1	1.0e-6	1.0e-6	$integer::hint_bits = 0x1;
84
85				# spent 18µs within integer::import which was called 2 times, avg 9µs/call: # once (10µs+0) by Astro::Time::BEGIN or Astro::Time::mjd2cal at line 866 of /wise/base/static/lib/perl5/site_perl/5.10.0/Astro/Time.pm # once (8µs+0) at line 7 of /opt/wise/lib/perl5/5.10.0/Time/Local.pm sub import {
86	2	5.0e-6	2.5e-6	$^H \|= $integer::hint_bits;
87				}
88
89				sub unimport {
90				$^H &= ~$integer::hint_bits;
91				}
92
93	1	5.0e-6	5.0e-6	1;