Matlab的两种移位运算：

1） circshift 矩阵移位

circshift ：Shift array circularly

Syntax ： B = circshift(A,shiftsize)

Description ：

B = circshift(A,shiftsize) circularly shifts the values in the array, A, by shiftsize elements. shiftsize is a vector of integer scalars where the n-th element specifies the shift amount for the n-th dimension of array A. If an element in shiftsize is positive, the values of A are shifted down (or to the right). If it is negative, the values of A are shifted up (or to the left). If it is 0, the values in that dimension are not shifted.

Example ：

Circularly shift first dimension values down by 1.
A = [ 1 2 3;4 5 6; 7 8 9]
A =
     1     2     3
     4     5     6
     7     8     9

B = circshift(A,1)
B =
     7     8     9
     1     2     3
     4     5     6

Circularly shift first dimension values down by 1 and second dimension values to the left by 1.
B = circshift(A,[1 -1]);
B =
    8     9     7
    2     3     1
    5     6     4

2）bitshift 位移位

bitshift ：
Shift bits specified number of places

Syntax ：

C = bitshift(A, k)
C = bitshift(A, k, n)

Description ：

C = bitshift(A, k) returns the value of A shifted by k bits. Input argument A must be an unsigned integer or an array of unsigned integers. Shifting by k is the same as multiplication by 2^k. Negative values of k are allowed and this corresponds to shifting to the right, or dividing by 2^abs(k) and truncating to an integer. If the shift causes C to overflow the number of bits in the unsigned integer class of A, then the overflowing bits are dropped.

C = bitshift(A, k, n) causes any bits that overflow n bits to be dropped. The value of n must be less than or equal to the length in bits of the unsigned integer class of A (e.g., n <= 32 for uint32).

Instead of using bitshift(A, k, 8) or another power of 2 for n, consider using bitshift(uint8(A), k) or the appropriate unsigned integer class for A.

Examples：

Example 1
Shifting 1100 (12, decimal) to the left two bits yields 110000 (48, decimal).
C = bitshift(12, 2)
C =
    48

Example 2

Repeatedly shift the bits of an unsigned 16 bit value to the left until all the nonzero bits overflow. Track the progress in binary:
a = intmax('uint16');
disp(sprintf( ...
   'Initial uint16 value %5d is %16s in binary', ...
   a, dec2bin(a)))

for k = 1:16
   a = bitshift(a, 1);
   disp(sprintf( ...
      'Shifted uint16 value %5d is %16s in binary',...
      a, dec2bin(a)))
   end