Denotes the current output location.
The period always refers to a location in a sections segment, so is valid only in a sections-section definition. Within such a definition, ' . ' may appear anywhere a symbol is valid.
Assigning a new, greater value to ' . ' causes the location counter to advance. But it is not possible to decrease the location-counter value, so it is not possible to assign a new, lesser value to ' . ' You can use this effect to create empty space in an output section, as the Moving the Location Counter example does.
The code of Moving the Location Counter moves the location counter to a position 0x10000 bytes past the symbol __start .
..data :
{
*.(data)
*.(bss)
*.(COMMON)
__start = .;
. = __start + 0x10000;
__end = .;
} > DATA