Equivalent for NOP in C for Embedded?
There's an intrinsic
nop in most compilers, Keil should have this as well - try
See - http://www.keil.com/support/man/docs/armccref/armccref_CJABCDAD.htm
Intrinsic functions are usually safer than directly adding assembly code for compatibility reasons.
Does this vary with the embedded controller that I use?
Yes. Inline assembly is not part of the C standard (yet), it varies from compiler to compiler and sometimes even between different target architectures of the same compiler. See Is inline asm part of the ANSI C standard? for more information.
For example, for the
C51 Keil compiler, the syntax for inline assembly is
ARM, the syntax is something like
You will need to check the manual for the actual compiler you are using.
For some of the more common opcodes, some compilers provide so-called intrinsics - these can be called like a C function but essentially insert assembly code, like