What is push in assembly?

The push instruction places its operand onto the top of the hardware supported stack in memory. Specifically, push first decrements ESP by 4, then places its operand into the contents of the 32-bit location at address [ESP].

What is caller callee convention and why is it needed?

Callee vs caller saved is a convention for who is responsible for saving and restoring the value in a register across a call. ALL registers are “global” in that any code anywhere can see (or modify) a register and those modifications will be seen by any later code anywhere.

What are the calling conventions of the x86 compiler?

List of x86 calling conventions Archi­tecture Name Operating system, compiler Parameters Stack cleanup Registers Stack order 8086 cdecl Caller 8086 Pascal Callee 8086 fastcall (non-member) Microsoft AX, DX, BX Callee

Why are function call conventions used in C?

This convention is the most common because it supports semantics required by the C language. The C language supports variadic functions (variable argument lists, à la printf), and this means that the callermust clean up the stack after the function call: the called function has no way to know how to do this.

What does the call convention in Win32 mean?

Also known as __pascal, this requires that each function take a fixed number of parameters, and this means that the calledfunction can do argument cleanup in one place rather than have this be scattered throughout the program in every place that calls it. The Win32 API primarily uses __stdcall.

Is the C calling convention based on hardware?

The C calling convention is based heavily on the use of the hardware-supported stack. To understand the C calling convention, you should first make sure that you fully understand the push, pop, call, and ret instructions – these will be the basis for most of the rules.