汇编编程比高级语言(如c)花费更长的时间,更难编程,这似乎是一种主流观点。因此,出于这些原因以及更好的可移植性,似乎建议或假设用高级语言编写更好。

最近我一直在用x86汇编语言写作,我开始意识到这些原因可能都不是真的,除了可移植性。也许这更多的是一个熟悉的问题,知道如何写好汇编。我还注意到在汇编中编程与在HLL中编程有很大的不同。也许一个好的、有经验的汇编程序员可以像一个有经验的C程序员用C写程序一样轻松、快速地编写程序。

也许是因为汇编编程与hll有很大的不同,因此需要不同的思维、方法和方式,这使得对不熟悉的人编写程序看起来非常尴尬,因此给汇编编程带来了不好的名声。

如果可移植性不是问题,那么C语言比NASM这样的优秀汇编器有什么优势呢?

编辑: 我只是想指出。当你用汇编语言写作时,你不必只写指令代码。您可以使用宏、过程和您自己的约定来进行各种抽象,使程序更模块化、更可维护、更易于阅读。这就是熟悉如何编写好的汇编的原因。


当前回答

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。

其他回答

$$$

一家公司雇佣一名开发人员来帮助将代码转化为$$$。越快地生成有用的代码,公司就能越快地将代码转化为利润。

高级语言通常更擅长生成大量有用的代码。这并不是说集会没有它的位置,因为在有些时候和地方,没有别的方法可以。

合理水平的汇编能力是一项有用的技能,特别是当您从事任何类型的系统级或嵌入式编程时,这并不是因为您必须编写那么多汇编程序,而是因为有时了解盒子的实际功能非常重要。如果您对汇编程序的概念和问题没有低级的理解,这可能会非常困难。

然而,至于在汇编器中实际编写大量代码,有几个原因导致它做得不多。

There's simply no (almost) need. Except for something like the very early system initialization and perhaps a few assembler fragments hidden in C functions or macros, all very low-level code that might once have been written in assembler can be written in C or C++ with no difficulty. Code in higher-level languages (even C and C++) condenses functionality into far fewer lines, and there is considerable research showing that the number of bugs correlates with the number of lines of source code. Ie, the same problem, solved in assembler and C, will have more bugs in assembler simply because its longer. The same argument motivates the move to higher level languages such as Perl, Python, etc. Writing in assembler, you have to deal with every single aspect of the problem, from detailed memory layout, instruction selection, algorithm choices, stack management, etc. Higher level languages take all this away from you, which is why are so much denser in terms of LOC.

从本质上讲,以上所有内容都与汇编程序与C或其他语言中可用的抽象级别有关。汇编程序迫使您自己制作所有的抽象,并通过您自己的自律来维护它们,而任何中级语言,如C,特别是高级语言,都可以为您提供开箱即用的抽象,以及相对容易地创建新抽象的能力。

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。

汇编在不同的微处理器之间是不可移植的。

Oh hai, I'm a dataflow system. This App I'm running, are full of varrrious components. It's a distributed app, and it resides in 3 computers, on a powerful x86 and two smaller ARMs. Most of the components are written in C++, but there is a critical one written in ASM for the x86. Also, most components have several variations: compiled for different processors, also some components have special GPU versions. Shame or not, I have a script component (a wrapper component calls a script), which prints report, but only once a year. It doesn't even hurt that it's just a script, a slow script.

作为一个智能数据流应用程序,我知道,我的架构只适合特定的任务,其中信号/数据通过图形流动,例如自动化,视频/图像处理,音频处理(所有合成器使用数据流),但幸运的是,这些应用领域是非常需要功率的,其中优化是必不可少的。

我很确定有一天会出现一些其他的架构,它们也是关于优化(以及其他让编程更容易等的东西),它们将能够覆盖更多或其他领域,而我,数据流不能。

因此,“C vs ASM”的话题并不是一个真正的困境。这就像是在争论数字合成器还是模拟合成器更好(就像我之前提到的,我一直在研究合成器)。我建议,做好听的音乐。或倾听。无论什么。C不是相对于ASM。无论如何,我从未见过一个C程序被ASM攻击,反之亦然。

对不起,我的英语不好,尽管我不是一个新技术,我不是广为人知,我是一个孩子。很有希望。来,看看我的资料!