有没有的C任何非二进制补码实现的？ [英] Are there any non-twos-complement implementations of C?

问题描述

<一个href=\"http://stackoverflow.com/questions/3952123/re$p$psentation-of-negative-numbers-in-c/3952262#3952262\">As大家都毫无疑问知道，ISO C标准（和C ++为好，我想，虽然我在C面更感兴趣）允许有符号数的三个基本重新presentations：

As we all no doubt know, the ISO C standard (and C++ as well, I think, though I'm more interested on the C side) allows three underlying representations of signed numbers:

• 补;


• 一补数;和


• 登入/幅度。

维基百科条目指出符号/幅度用于在IBM 7090从60年代，和一补数所使用的PDP-1，CDC 160A和UNIVAC 1100，所有这些都可以追溯到20世纪60年代为好。

Wikipedia's entry states that sign/magnitude is used on the IBM 7090 from the 60s, and that ones' complement is used by the PDP-1, CDC 160A and UNIVAC 1100, all of which date back to the 60s as well.

是否有C（或底层硬件）与这些替代重presentations任何其他实现，已经不是五十年前问世多一点最近（和他们是什么）？

Are there any other implementations of C (or underlying hardware) with these alternative representations, that have come out a little more recently than fifty years ago (and what are they)?

这似乎有点浪费，以保持在什么机器不再存在的一个标准。

It seems a little wasteful to keep something in a standard for machines no longer in existence.

推荐答案

最近的例子我能找到的是 UNISYS 2200 系列的基础上，UNIVAC，与那些补算法。各种模型，1986年和1997年之间生产，但操作系统仍处于积极开发迟至2013 。他们也有一个C编译器，因为这里看到。

The most recent example I can find is the UNISYS 2200 series, based on UNIVAC, with ones-complement arithmetic. The various models were produced between 1986 and 1997 but the OS was still in active development as late as 2013. They also had a C compiler, as seen here.

这很可能是他们仍然可能会在使用中今天。

It seems likely that they may still be in use today.

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