Visual C ++中固有的128位除法 [英] 128-bit division intrinsic in Visual C++

问题描述

我想知道Visual C ++中是否真的没有128位除法内在函数?

I'm wondering if there really is no 128-bit division intrinsic function in Visual C++?

有一个称为_umul128()的64x64 = 128位乘法内在函数，与MUL x64汇编程序指令很好地匹配.

There is a 64x64=128 bit multiplication intrinsic function called _umul128(), which nicely matches the MUL x64 assembler instruction.

自然地，我假设也将有一个内在的128/64 = 64位划分(对DIV指令进行建模)，但是令我惊讶的是，Visual C ++和Intel C ++似乎都没有，至少没有列出在intrin.h中.

Naturally, I assumed there would be a 128/64=64 bit division intrinsic as well (modelling the DIV instruction), but to my amazement neither Visual C++ nor Intel C++ seem to have it, at least it's not listed in intrin.h.

有人可以确认吗?我尝试对编译器可执行文件中的函数名称进行grep'ing操作，但首先找不到_umul128，所以我想我找错了位置.

Can someone confirm that? I tried grep'ing for the function names in the compiler executable files, but couldn't find _umul128 in the first place, so I guess I looked in the wrong spot.

更新:至少我现在在Visual C ++ 2010的c1.dll中找到了模式umul128(不带下划线).所有其他内在函数都在其周围列出，但不幸的是，没有"udiv128"之类的内容: (因此，似乎他们真的已经忘记了"实现它.

Update: at least I have now found the pattern umul128 (without the leading underscore) in c1.dll of Visual C++ 2010. All the other intrinsics are listed around it, but unfortunately no "udiv128" or the like :( So it seems they really have "forgotten" to implement it.

要澄清一下:我不仅在寻找128位数据类型，而且还在寻找一种用C ++将128位标量int除以64位int的方法. 固有函数或 native 128位整数支持都可以解决我的问题.

To clarify: I'm not only looking for a 128-bit data type, but a way to divide a 128-bit scalar int by a 64-bit int in C++. Either an intrinsic function or native 128-bit integer support would solve my problem.

答案是否定的，直到2017年为止Visual Studio 2010中都没有内在的_udiv128，但是在Visual Studio 2019 RTM中可用.

The answer is no, there is no _udiv128 intrinsic in Visual Studio 2010 up to 2017, but it is available in Visual Studio 2019 RTM

推荐答案

我不是专家，但我对此进行了挖掘:

I am no expert, but I dug this up:

http://research.swtch.com/2008/01/Division-via-multiplication.html

有趣的东西.希望对您有所帮助.

Interesting stuff. Hope it helps.

这也很有见地: http://www.gamedev. net/topic/508197-x64-div-intrinsic/

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