https://devzone.nordicsemi.com/f/nordic-q-a/15819/inline-assemblerGood day, I try to add inline assembler like this: asm(&quot;POP {R12,PC}&quot;); but I have an error: Error[Og006]: Error in inline assembly: &quot;Error[401]: Operand syntax error&quot; I have read that I should change the processor mode in code settingsen-USTelligent Community 13Thu, 18 Aug 2016 10:23:04 GMThttps://devzone.nordicsemi.com/thread/60397?ContentTypeID=1Thu, 18 Aug 2016 10:23:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:78a8815b-9146-439f-91e5-0579d2eb4169Susheel Nuguru<p>This is not a Nordic related question, This is purely ARM related.</p> <p>Please read the post about push and pop <a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0497a/BABIAJHJ.html">here</a></p> <p>You cannot use registers after R7 in these operations</p> <blockquote> <p>3.4.6. PUSH and POP<br /> Restrictions In these instructions:</p> <ul> <li>reglist must use only R0-R7.</li> <li>The exception is LR for a PUSH and PC for a POP.</li> </ul> </blockquote> <p>change your asm to <code>asm(&quot;POP {R7,PC}&quot;)</code>; and it should work.</p><div style="clear:both;"></div>