Pointer Dereferencing

Take this C code as example:

// this is defined globally.
int globalVar;
// These lines of code are part of some function
int b;
int * ptr;
ptr = &globalVar;
*ptr = 100;
b = *ptr;

Generated assembly code:

movl    $globalVar, -4(%ebp)
movl    -4(%ebp), %eax
movl    $100, (%eax)
movl    -4(%ebp), %eax
movl    (%eax), %eax
movl    %eax, -8(%ebp)

Location of local variables of the stack (local variables are explained here)

ptr => -4(%ebp)
b => -8(%ebp)

The use of registers as temporary memory is described here
Comments on generated assembly code:

# ptr = &globarVar
    movl    $globalVar, -4(%ebp)

# tmp = ptr
    movl    -4(%ebp), %eax

# *tmp = 100
    movl    $100, (%eax)

# tmp = ptr
    movl    -4(%ebp), %eax

# tmp = *tmp
    movl    (%eax), %eax

# b = tmp
    movl    %eax, -8(%ebp)