是否有 C 的任何非二进制补码实现? [英] Are there any non-twos-complement implementations of C?
问题描述
众所周知，ISOC 标准(以及 C++，我认为，虽然我对 C 方面更感兴趣)允许有符号数的三种底层表示:
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:
- 补码；
- ones 的补码；和
- 符号/大小.
维基百科的条目指出，符号/幅度用于 60 年代的 IBM 7090，而 PDP-1、CDC 160A 和 UNIVAC 1100 使用的是符号/幅度，所有这些都可以追溯到 60 年代.
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.
是否有任何其他具有这些替代表示的 C(或底层硬件)实现，它们是在五十年前出现的(它们是什么)?
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)?
将某些东西保留在不再存在的机器的标准中似乎有点浪费.
It seems a little wasteful to keep something in a standard for machines no longer in existence.
推荐答案
我能找到的最新例子是 UNISYS 2200 系列，基于 UNIVAC，具有补码算法.各种型号是在 1986 年到 1997 年之间生产的，但操作系统仍在积极开发中最迟到 2015 年.他们还有一个 C 编译器，如此处所示.
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 2015. They also had a C compiler, as seen here.
它们今天似乎仍在使用.
It seems likely that they may still be in use today.
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