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What is stack in assembly?
A stack is an array-like data structure in the memory in which data can be stored and removed from a location called the ‘top’ of the stack. The memory space reserved in the stack segment is used for implementing stack. The registers SS and ESP (or SP) are used for implementing the stack.
What is push in NASM?
push src. Insert a value onto the stack. Useful for passing arguments, saving registers, etc. push ebp. pop dest.
Do registers have addresses?
Registers are the internal processor storage. They do not have memory addresses, because they do not reside in memory. You identify them by their names: EAX, for example.
What happens when you pop a register?
“push” stores a constant or 64-bit register out onto the stack. “pop” retrieves the last value pushed from the stack. Everything you push, you MUST pop again at some point afterwards, or your code will crash almost immediately!
What is push or pop?
A. P. Instructions that store and retrieve an item on a stack. Push enters an item on the stack, and pop retrieves an item, moving the rest of the items in the stack up one level. See stack.
Where does the return address go in NASM?
After the parameters are pushed, the call instruction is made, so when the called function gets control, the return address is at [rsp], the first memory parameter is at [rsp+8], etc. The stack pointer rsp must be aligned to a 16-byte boundary before making a call.
How are parameters pushed on the stack in NASM?
Additional parameters are pushed on the stack, right to left, and are to be removed by the caller after the call. After the parameters are pushed, the call instruction is made, so when the called function gets control, the return address is at [rsp], the first memory parameter is at [rsp+8], etc.
How many integer registers are there in NASM?
The 16 integer registers are 64 bits wide and are called: (Note that 8 of the registers have alternate names.) You can treat the lowest 32-bits of each register as a register itself but using these names: You can treat the lowest 16-bits of each register as a register itself but using these names:
Which is the plain Register called in NASM?
The number is called the displacement; the plain register is called the base; the register with the scale is called the index . These can be written in many ways. Here are some examples from the official docs.