Bit manipulation of JavaScript, integer, binary

　　bit and (x&y): binary operation of the operand, if the two operand of a two is 1, the corresponding result bit is set to 1.

0x0007 & 0x0003 = 0x0003

\

A small old brown dog: 64 + 16 + 8 + 2 = 90

Search for a pet with a specific tag, only need to do bit and operation with the search value.

Search large young white pet var searchFlags = + + + 4;var pets = []; Pet var numpets = Pets.length;for (var i = 0; i < numpets; i++) {if (searchFlags & pets[i].flags = = SearchFlags) {}}

bit or (x|y): Binary or operation of the operand, if one of the two operands has one for 1, the corresponding result bit is set to 1.

0x0007 | 0x0003 = 0x0007

　　bitwise XOR (X^Y): A binary XOR operation on the operand, if only one of the two operands is 1, the corresponding result bit is set to 1.

0x0001 ^ 0x0000 = 0x0001 0x0001 ^ 0x0001 = 0x0000

Toggle is converted between 0 and 1 (assuming that the start toggle equals 0 or 1) toggle ^= 1;toggle = toggle? 0:1;

bit non (~x): All bits are reversed (if the operand is a signed integer (the leftmost bit is the sign bit), the ~ operator equals minus 1).

11100111 Inversion is 00011000

　　bit left shift (x<<numbits): numbits bits to the left of the binary of X. All bits are shifted to the left, the leftmost bits are lost, and 0 fills the right-most bit. Multiplication x* equivalent to unsigned integers (2^numbits)

y = 5 << 1; y=10; = = Math.floor (5* (2^1)) y = 5 << 2; y=20; = = Math.floor (5* (2^2)) y = 5 << 3; y=40; = Math.floor (5* (2^3))

arithmetic bit left shift (x>>numbits): numbits bits to the right of the binary of X. In addition to the leftmost sign bit, all bits move to the right and the right bit is lost. Division x/(2^numbits) equivalent to signed integers

y = 5 >> 1; y=5; = = Math.floor (5/(2^1)) y = 5 >> 2; y=2; = = Math.floor (5/(2^2)) y = 5 >> 3; Y=1; = = Math.floor (5/(2^3)) x = y >> 0; is a fast x = Math.floor (y)

Bit manipulation of JavaScript, integer, binary