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    <p>Typically, the r-value is "stored" within the program itself.</p> <p>In other words, the compiler itself (<em>before the program is ever run</em>) computes the 10 + 5 - 3 value (it can do so since since it is all based on constant immediate values), and it emits the assembly code to store the result of this calculation in whatever l-value for the assignement (in this case, the variable named a, which the compiler probably knows as a relative address to a data segment origin of sorts).</p> <p>The r-value, which has a value of 12 is therefore only found inside the binary of the program, within a assembly instruction that <em>looks</em> like </p> <pre><code> mov &lt;some dest, typically DS-relative&gt;, $0C </code></pre> <p>$0C is the "r-value".</p> <p>If the r-value happened to be the result of a calculation that can only done at run-time, say if the underlying c code was: a = 17 * x; // x some run time var, the r-value would too be "stored" (or rather materialized) as a series of instructions within the program binary. The difference with the simple "mov dest, imm" above is that it would take several instructions to load the variable x in an accumulator, multiply by 17 and store the result at the address where the variable a is. It is possible that the compiler may "authorize itself" ;-) to use the stack for some intermediate result etc. but such would be<br> a) completely compiler dependent<br> b) transiant<br> c) and typically would only involve <em>part</em> of the r-value<br> it is therefore safe to say that the r-value is a compile-time concept which is encapsulated in parts of the program (not the data), and isn't stored anywhere but in the program binary.</p> <p>In response to paxdiablo: the explanation offered above is indeed restrictive of the possibilities because the c standard effectively does <em>not</em> dictate anything of that nature. Never the less, most any r-value is eventually materialized, at least in part, by some instructions which sets things up so that the proper value, whether calculated (at run time) or immediate gets addressed properly.</p>
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    1. COI think he's asking where are the different parts of the code located in the stack.
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    2. CO*Nothing* in the C standard mandates this behavior. You should say: "Typically, the r-value is ...".
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    3. CO@paxdiablo. Agreed and edited with "Typically, " I also added a small paragraph at the bottom, do you concur with it ?
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