Menu
Search

API Documentation

version 2.096.0

overview

View source code
Display the source code in std/bitmanip.d from which this page was generated on github.
Report a bug
If you spot a problem with this page, click here to create a Bugzilla issue.
Improve this page
Quickly fork, edit online, and submit a pull request for this page. Requires a signed-in GitHub account. This works well for small changes. If you'd like to make larger changes you may want to consider using local clone.

Struct std.bitmanip.DoubleRep

Allows manipulating the fraction, exponent, and sign parts of a double separately. The definition is:

struct DoubleRep ; 
struct DoubleRep
{
    union
    {
        double value;
        mixin(bitfields!(
                  ulong,   "fraction", 52,
                  ushort,  "exponent", 11,
                  bool,    "sign",      1));
    }
    enum uint bias = 1023, signBits = 1, fractionBits = 52, exponentBits = 11;
}

Example

DoubleRep rep = {value: 0};
writeln(rep.fraction); // 0
writeln(rep.exponent); // 0
assert(!rep.sign);

rep.value = 42;
writeln(rep.fraction); // 1407374883553280
writeln(rep.exponent); // 1028
assert(!rep.sign);

rep.value = 10;
writeln(rep.fraction); // 1125899906842624
writeln(rep.exponent); // 1026

Example

DoubleRep rep = {value: 1};
writeln(rep.fraction); // 0
writeln(rep.exponent); // 1023
assert(!rep.sign);

rep.exponent = 1022;
writeln(rep.value); // 0.5

rep.exponent = 1026;
writeln(rep.value); // 8

Example

DoubleRep rep = {value: 1};
rep.value = -0.5;
writeln(rep.fraction); // 0
writeln(rep.exponent); // 1022
assert(rep.sign);

rep.value = -1. / 3;
writeln(rep.fraction); // 1501199875790165
writeln(rep.exponent); // 1021
assert(rep.sign);

Example

Reading 

DoubleRep x;
x.value = 1.0;
assert(x.fraction == 0 && x.exponent == 1023 && !x.sign);
x.value = -0.5;
assert(x.fraction == 0 && x.exponent == 1022 && x.sign);
x.value = 0.5;
assert(x.fraction == 0 && x.exponent == 1022 && !x.sign);

Example

Writing 

DoubleRep x;
x.fraction = 1125899906842624;
x.exponent = 1025;
x.sign = true;
writeln(x.value); // -5.0

Authors

Walter Bright, Andrei Alexandrescu, Jonathan M Davis, Alex Rønne Petersen, Damian Ziemba, Amaury SECHET

License

Boost License 1.0.