user28215: I am working on a project involving an Aduino and screen.
As i was going through the u8glib (Arduino Monochrome Graphics Library for LCDs and OLEDs), something caught my attention:
#define U8G_ESC_DLY(x) 255, ((x) & 0x7f)
#define U8G_ESC_CS(x) 255, (0xd0 | ((x)&0x0f))

How can i interpret this macro for a given x value ?

user368: 
How can i interpret this macro for a given x value ?

As normal. First expand the macro, and then worry about what the comma means in context. In an expression the result is the expression on the right of the comma. In a function call it stands in for two arguments. Just look at where it's used and that's what it will mean.

28215: <p>I am working on a project involving an Aduino and screen.</p>

<p>As i was going through the <a href="https://github.com/olikraus/u8glib" rel="nofollow noreferrer">u8glib (Arduino Monochrome Graphics Library for LCDs and OLEDs)</a>, something caught my attention:</p>

<pre><code>#define U8G_ESC_DLY(x) 255, ((x) &amp; 0x7f)
#define U8G_ESC_CS(x) 255, (0xd0 | ((x)&amp;0x0f))
</code></pre>

<p>How can i interpret this macro for a given x value ?</p>
 368: <blockquote>
  <p>How can i interpret this macro for a given x value ?</p>
</blockquote>

<p>As normal. First expand the macro, and <em>then</em> worry about what the comma means in context. In an expression the result is the expression on the right of the comma. In a function call it stands in for two arguments. Just look at where it's used and that's what it will mean.</p>
