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