在Java中处理四倍精度浮点数(128位) [英] Handling a quadruple precision floating point (128-bit) number in java

问题描述

我需要利用来自另一个系统的数字，这些数字是Java中的128位(四精度)浮点数.

I need to make use of numbers coming from another system that are 128-bit (quadruple-precision) floating point numbers in java.

考虑到Java中没有等效类型，我想使用Java代码降低数字的精度，以便将它们存储在Java double中.可以在c或使用汇编中相当容易地完成此操作，但我只想在java中完成.

Considering that there is no equivalent type in java, I would like to reduce the precision of the numbers using java code so they can be stored in a java double. This can be done fairly easily in c or using assembly but I would like to do it purely in java.

公平地假设四精度数存储在Java中的128位字节数组中.

It is fair to assume that the quadruple-precision number is stored in a 128-bit byte array in java.

仅使用java是否有一个好的解决方案?谢谢.

Is there a good solution, using only java? Thanks.

推荐答案

这个问题让我很感兴趣，以至于我不得不写一个库来处理IEEE-754浮点数.使用该库，您可以使用以下内容:

I was so intrigued by this question that I was compelled to write a library to handle IEEE-754 floating point numbers. With the library, you can use the following:

byte[] quadBytes; // your quad-floating point number in 16 bytes
IEEE754 quad = IEEE754.decode(IEEE754Format.QUADRUPLE, 
        BitUtils.wrapSource(quadBytes));
// IEEE754 holds the number in a 'lossless' format

从那里，您可以:

ByteBuffer doubleBuffer = ByteBuffer.allocateDirect(8);
quad.toBits(IEEE754Format.DOUBLE, BitUtils.wrapSink(doubleBuffer));
doubleBuffer.rewind();
double converted = doubleBuffer.asDoubleBuffer().get();

但是上面的代码片段只是为了说明一般用法...为double提供了简写:

But the above snippet is just to illustrate general usage... a shorthand is provided for double:

double converted = quad.doubleValue();

该代码可从 kerbaya.com/ieee754lib 获得.

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