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Alias std.bitmanip.DoubleRep
Allows manipulating the fraction, exponent, and sign parts of a
double
separately. The definition is:
alias DoubleRep
= std .bitmanip .FloatingPointRepresentation!(double);
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
FloatRep rep = {value: 0};
writeln(rep .fraction); // 0
writeln(rep .exponent); // 0
assert(!rep .sign);
rep .value = 42;
writeln(rep .fraction); // 2621440
writeln(rep .exponent); // 132
assert(!rep .sign);
rep .value = 10;
writeln(rep .fraction); // 2097152
writeln(rep .exponent); // 130
Example
FloatRep rep = {value: 1};
writeln(rep .fraction); // 0
writeln(rep .exponent); // 127
assert(!rep .sign);
rep .exponent = 126;
writeln(rep .value); // 0.5
rep .exponent = 130;
writeln(rep .value); // 8
Example
FloatRep rep = {value: 1};
rep .value = -0.5;
writeln(rep .fraction); // 0
writeln(rep .exponent); // 126
assert(rep .sign);
rep .value = -1. / 3;
writeln(rep .fraction); // 2796203
writeln(rep .exponent); // 125
assert(rep .sign);
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
Copyright © 1999-2022 by the D Language Foundation | Page generated by ddox.