Yes, it is just ARM assembly. But the tooling (Clang vs GCC) and the operation system differ, so the code from the book won't work without changes on a Mac. The book already contains a chapter for using the ARM assembly on iOS, because you have to do the same changes vs. running the sample code on Linux. The linked blog posts lists these changes. They are not large, but significant enough, that someone learning how to code in ARM assembly will be thankful for adjusted example code.