dest = dest & source
The and instruction ands the source value (second operand) to the destination (either a register or a memory location). The destination can be a 64, 32, 16 or 8 bit register or memory location. The source can be either a register, memory location or an immediate value. You can not use 2 memory addresses.
The operation performs a bitwise and of the 2 operands. In my description and is a bit selector - the second operand is a mask selecting certain bits of the first operand. Here is an example of a bitwise and.
1010010010101011
& 1010101010100111
----------------
1010000010100011
Some examples of using and:
and rax, 0xffff ; and rax with 0xffff
; selects the lowest 16 bits of rax
and eax, 0xff00 ; and eax with 0xff00
; fills upper half of rax with 0
and dx, ax ; ands dx and ax, result in dx
; leaves the rest of rdx alone
and rax, [y] ; ands rax with 64 bit variable y
and [x], eax ; ands 32 bit varaible x with eax