x86 Assembly Language Part-II

[Music] let us start this part by describing the move instruction so the move instructions arguably the most versatile instruction in the x86 instruction set so it can actually do a lot so in terms of risk instructions it combines it's it's a combination of three things so in uh so if you would recall in the risk

instruction set we used to have a move instruction which was nowhere as powerful as this so the move instruction in the risk instruction set was is actually moving the value of a registor or a constant to a resistor so the cisk move instruction does that so we can think of it as a risk move plus

it's also a load so it can load a value from memory and put it in a register and it's also a store so it can store something from a register to a memory address so the move instruction in x86 is equivalent to a risk move a load and a store all combined into

one so what is the semantics the semantics is very simple uh the semantics is that uh uh the move instruction takes two operant the first operant is a source as well as a destination right so it can either be a register or a memory the second operant is clearly a source so it can be a

register a memory or an immediate so uh as as discussed in some of the earlier slides that uh most x86 instructions are actually in a two address format they take two operant and the first operant is both a source as well as a destination uh so so we shall see this is a standard format for almost all

instructions so uh here the idea is like this so but in the move for the case of the move instruction we the uh you know the duality of a source and a destination is not very important so we'll not uh over stress on this aspect here so so let's consider an example let's say we write move mov eax comma