JavaScript 32-bit integer unsigned operation example

Source: Internet
Author: User
Tags bitwise numeric numeric value

All integer variables default to signed integers, JavaScript bitwise operation, is the use of 32-bit signed integer, which means that the result of its conversion is also a 32-bit signed integral type

In JavaScript, all integer numeric variables are signed by default, what does that mean?  A signed integer uses a 31-bit numeric value that represents an integer, a symbol with a 32nd digit integer, 0 for a positive number, and a 1 for negative numbers.    The range of values ranges from -2^31-2^31-1 2147483648 to 2147483647. When JavaScript is bit-operated, a 32-bit signed integer is used, which means that the result of the conversion is also a 32-bit signed integer.    In some cases, we will have unexpected results of the shift, the following is the C language and JS contrast.  C language code is as follows: unsigned int a = 3774191835u;  unsigned int b = a >> 2;  /* b = = 943547958 * * JavaScript code is as follows: var a = 3774191835;  var B = a >> 2; /* b = = 130193866/Can be seen, JavaScript for bitwise operation, is the use of signed integer type, so we got a different result.    How to solve it? We can convert the number of symbols in JavaScript into unsigned numbers.    Just need to do >>>0 shift operation is good. It is best not to use >>, recommended >>> because the leftmost one will be resolved into a sign bit, when the number overflows, will be resolved into negative numbers.

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