What is far pointer and its uses?

Answer 1

It's good for accessing data in large applications.

AnswerDefinition: A far pointer in segmented architecture computer is a pointer which includes segment number to address the entire 1mb memory which is available under Dos.

example: int main() {

int a; a=10; printf("%d",&a); return 0;

} Explanation:

When this code is saved/compiled the processor allocates a small amount of memory and memor address is given between the memory range 0 to 65,535.Which is part of the 1mb dos memory ie(10,48,780)bytes.If you want to store data/code beyond the memory range and any where in that 1mb memory.You can do that using the far pointers.By declaring a variable as 'far'pointer.The compiler tells the processor to allocate memory for that specific data/code to perform a specific process in that specific address.The address which is exceeds the 65,535 memory range if referred using the 4 digit hexadecimal number,using the two CPU registers namely segment,offset. While referring to memory address greater than 65,535,the 1mb dos memory is divided into segments,Each segment containing 0 to 65,535 locations(64kb) and to refer these segments the segment register is used.The offset regsiter is used to refer the 65,535 locations present in each segment. So using these two registers(segment:offset)we can refer the entire 1mb memory avialable in Dos.And it is done by writing the segment and offset address side by side like this B8000000.The first four hexadecimal digit represents the segment address and the last four hexadecimal address represents the offset address.