比较运算符的速度 [英] Speed of Comparison operators

问题描述

在诸如……之类的语言中，两个运算符均<和< =(及其对立)存在.哪个会更快，以及如何解释它们?

In languages such as... well anything, both operators for < and <= (and their opposites) exist. Which would be faster, and how are they interpreted?

if(x< = y){等等； }

if (x <= y) { blah; }

或

if(x< y + 1){等等； }

if (x < y + 1) { blah; }

推荐答案

假定没有编译器优化(大的假设)，第一个将更快，因为< =由单个jle指令实现，而后者需要加一个jl指令.

Assuming no compiler optimizations (big assumption), the first will be faster, as <= is implemented by a single jle instruction, where as the latter requires an addition followed by a jl instruction.

http://en.wikibooks.org/wiki/X86_Assembly/Control_Flow#Jump_if_Less

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