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lib/Lab/Data/Analysis/WaveRunner.pm  view on Meta::CPAN

    my $f   = $str & 0x007FFFFF;
    my $w   = ( 2**( $e - 127 ) ) * ( 1 + ( $f / 0x00800000 ) );
    $w = -$w if $s;
    return $w;
}

sub double_from_hex { unpack 'd', scalar reverse pack 'H*', $_[0] }

use constant POS_INF => double_from_hex '7FF0000000000000';
use constant NEG_INF => double_from_hex 'FFF0000000000000';
use constant NaN     => double_from_hex '7FF8000000000000';

sub _double    # assumes MSB data input
{
    #    my ($bytes) = @_;
    #    my ($bottom, $top) = unpack ("LL", $bytes);
    my ( $top, $bottom ) = @_;

    # Reference:
    # http://en.wikipedia.org/wiki/Double_precision_floating-point_format

lib/Lab/Data/Analysis/WaveRunner.pm  view on Meta::CPAN

            return -0;
        }
        elsif ( $top == 0x7ff00000 ) {
            return POS_INF;
        }
        elsif ( $top == 0xfff00000 ) {
            return NEG_INF;
        }
    }
    elsif ( $top == 0x7ff00000 ) {
        return NaN;
    }
    my $sign = $top >> 31;

    #    print "sgn $sign\n";
    my $exponent = ( ( $top >> 20 ) & 0x7FF ) - 1023;

    #    print "e  = $exponent\n";
    my $e = ( $top >> 20 ) & 0x7FF;
    my $t = $top & 0xFFFFF;