C是一个宏汇编器!这是最好的一个!

它可以做几乎所有汇编程序可以做的事情，它是可移植的，在大多数极少数情况下，当它不能做一些事情时，你仍然可以使用嵌入式汇编代码。这就只留下了一小部分程序，你绝对需要用汇编来编写，而且只需要汇编。

更高层次的抽象和可移植性使大多数人更值得用c语言编写系统软件。尽管你现在可能不需要可移植性，但如果你在编写某个程序上投入了大量的时间和金钱，你可能不想把自己限制在将来可以使用它的地方。

我只能回答为什么我个人不经常用汇编编写程序，主要原因是这样做比较乏味。此外，我认为在没有立即注意到的情况下，更容易把事情搞砸。例如，你可能在一个例程中改变了使用寄存器的方式，但在另一个地方却忘记了这一点。它会很好地组装起来，直到很久以后你才会注意到。

也就是说，我确实认为组装仍然有有效的用途。例如，我有许多非常优化的汇编例程来处理大量数据，使用SIMD并遵循偏执的“每一个比特都是神圣的”[引用V.Stob]方法。(但请注意，简单的程序集实现通常比编译器为您生成的要糟糕得多。)

跟我们不再去外面厕所的原因一样，也跟我们不再说拉丁语和阿拉姆语的原因一样。

技术的出现使事情变得更容易，更容易获得。

编辑——为了不冒犯别人，我删除了某些词语。

作为一名大部分时间都在嵌入式编程领域工作的开发人员，我认为汇编语言还远远没有成为一种死亡/过时的语言。有某种接近金属级别的编码(例如，在驱动程序中)有时不能用高级语言准确或有效地表达。我们几乎所有的硬件接口例程都是用汇编程序编写的。

That being said, this assembly code is wrapped such that it can be called from C code and is treated like a library. We don't write the entire program in assembly for many reasons. First and foremost is portability; our code base is used on several products that use different architectures and we want to maximize the amount of code that can be shared between them. Second is developer familiarity. Simply put, schools don't teach assembly like they used to, and our developers are far more productive in C than in assembly. Also, we have a wide variety of "extras" (things like libraries, debuggers, static analysis tools, etc) available for our C code that aren't available for assembly language code. Even if we wanted to write a pure-assembly program, we would not be able to because several critical hardware libraries are only available as C libs. In one sense, it's a chicken/egg problem. People are driven away from assembly because there aren't as many libraries and development/debug tools available for it, but the libs/tools don't exist because not enough people use assembly to warrant the effort creating them.

最后，任何语言都有适用的时间和地点。人们使用他们最熟悉和最有成效的东西。在程序员的程序库中可能总会有汇编的位置，但是大多数程序员会发现他们可以用一种高级语言编写代码，这种语言在更少的时间内几乎同样高效。

如果一个普通的生产程序有10万行代码，每一行大约有8-12条汇编指令，那就是100万条汇编指令。

即使您可以以相当快的速度手写所有这些代码(请记住，这是您必须编写的8倍代码)，如果您想更改某些功能会发生什么?从这100万条指令中理解你几周前写的东西简直是一场噩梦!没有模块，没有类，没有面向对象的设计，没有框架，什么都没有。即使是为最简单的事情编写的类似代码的数量最多也令人生畏。

此外，你不能像高级语言那样优化你的代码。例如，C语言执行了大量的优化，因为你描述了你的意图，不仅仅是你的代码，在汇编程序中你只写代码，汇编程序不能对你的代码执行任何值得注意的优化。你写的就是你得到的，相信我，你不可能可靠地优化100万条指令，你在写的时候不断地打补丁。

随着汇编变得越来越不常见，出现了一个恶性循环:随着高级语言的成熟，汇编语言指令集的构建越来越少地是为了方便程序员，而更多地是为了方便编译器。

So now, realistically, it may be very hard to make the right decisions on, say, which registers you should use or which instructions are slightly more efficient. Compilers can use heuristics to figure out which tradeoffs are likely to have the best payoff. We can probably think through smaller problems and find local optimizations that might beat our now pretty sophisticated compilers, but odds are that in the average case, a good compiler will do a better job on the first try than a good programmer probably will. Eventually, like John Henry, we might beat the machine, but we might seriously burn ourselves out getting there.

Our problems are also now quite different. In 1986 I was trying to figure out how to get a little more speed out of small programs that involved putting a few hundred pixels on the screen; I wanted the animation to be less jerky. A fair case for assembly language. Now I'm trying to figure out how to represent abstractions around contract language and servicer policy for mortgages, and I'd rather read something that looks close to the language that the business folks speak. Unlike LISP macros, Assembly macros don't enforce much in the way of rules, so even though you might be able to get something reasonably close to a DSL in a good assembler, it'll be prone to all sorts of quirks that won't cause me problems if I wrote the same code in Ruby, Boo, Lisp, C# or even F#.

如果您的问题很容易用高效的汇编语言来表达，那么您的能力就更强了。