javascript Bitwise acceleration techniques.

1. If multiplied by a value of 2, you can use the left shift (Left Shift) to accelerate 300%.

x = x * 2;
x = x * 64;

equals:

x = x << 1; // 2 = 21
x = x << 6; // 64 = 26

2. If in addition to the previous one of the multiple values, you can use the right shift operation to accelerate 350%.

x = x / 2;
x = x / 64;

equals:

x = x >> 1;// 2 = 21
x = x >> 6;// 64 = 26

3. Incremental value by 10%.

x = int(1.232)

equals:

x = 1.232 >> 0;

4. Exchange two values (swap), the use of XOR can accelerate 20%.

var t:
t = a;
a = b;
b = t;

equals:

a = a^b;
b = a^b;
a = a^b;

5. Plus or minus conversion, you can add 300%.

i = -i;

equals:

i = ~i + 1; // NOT

equals:

i = (i ^ -1) + 1; // XOR

6. Take the remainder, if the divisor is a multiple of 2, you can use the AND operation to speed up the 600%.

x = 131 % 4;

equals:

x = 131 & (4 - 1);

7. Use the AND operation to check whether the integer is a multiple of 2, can accelerate 600%.

isEven = (i % 2) == 0;

equals:

isEven = (i & 1) == 0;

8. Accelerated Math.abs 600% of the written 1, writing 2 than the wording 1 to accelerate 20%.

i = x < 0 ? -x : x;

equals:

i = (x ^ (x >> 31)) - (x >> 31);

equals:

i=x^(~(x>>31)+1)+(x>>31);

9. Compare the two values after the multiplication of whether the same symbol, to accelerate 35%.

eqSign = a * b > 0;

equals:

eqSign = a ^ b > 0;

10. RGB color separation.

var bitColor = 0xff00cc;
var r = bitColor >> 16;
var g = bitColor >> 8 & 0xFF;
var b = bitColor & 0xFF;

11. RGB color merge

var r = 0xff;
var g = 0x00;
var b = 0xcc;
var bitColor:uint = r << 16 | g << 8 | b;