In the field of computer science, the concept of a stack is likely familiar to many.
The familiarity and understanding of stacks primarily stem from two aspects.
One aspect is that a stack is a type of data structure characterized by the Last In, First Out (LIFO) principle.
The other aspect is that a stack refers to a specific area of memory, which is often covered in courses related to the C programming language. This specific memory area is mainly used to store parameters for subroutine calls, and this memory space can also be used to define local variables.
The two reasons mentioned above are the main aspects that make stacks familiar to many people. In fact, I believe the term ‘stack’ is not a commonly used word, and it is relatively rare in everyday encounters.
In assembly language, the stack mechanism is a common mechanism used to temporarily store data. Here, I will briefly analyze some of its common usages.
The stack mechanism involves two aspects: establishing the stack and using the stack.
Establishing a stack requires specifying the SS segment register and the stack pointer SP register value. By specifying the values of these two registers, the location of the stack in memory is determined. The reason for using SS and SP to determine the memory location is that memory addresses are specified in the form of segment address: offset address, as mentioned in the previous article titled How to Understand the Conversion of “Segment Address: Offset Address” to Physical Address.
Using the stack mainly involves the push instruction PUSH and the pop instruction POP. Upon closer inspection, the main actions of these two instructions are to modify the value of the stack pointer SP and transfer data to a specified location. PUSH pushes data onto the stack, while POP pops data off the stack.
From this, I have derived several functions of the stack mechanism, meaning that using the stack can accomplish these operations.
1. Used for transferring data between registers. During push and pop operations, the same register can be used; if so, it serves to save the value of the register. If different registers are used, the stack mechanism can facilitate data exchange between different registers.
2. Used for transferring data between registers and memory. This requires setting the memory as the destination of the stack segment to exchange data between registers and memory.
3. Used for transferring data between memory locations. This also requires setting the corresponding memory space as the location of the stack segment.
4. Used to adjust the specific arrangement order of memory data. Since the push and pop operations of stack data have specific directions, data grows from high addresses to low addresses during push operations, and from low addresses to high addresses during pop operations. Utilizing this characteristic, it can be used to rearrange data in memory, such as reversing or ordering data.
The above are the four functions of the stack mechanism. Its function is somewhat similar to that of the instruction MOV, but I believe the stack may have other functions as well. This is just a brief introduction.
The stack is a relatively important concept in the field of computer science, and I hope we can understand it well and use it effectively.