The groundwork is done

That's the introduction behind you. You can read a line of PowerPC, you know where a function's arguments and return value live, and — as of the last chapter — you can recover a signature from nothing but the target in front of you.

Now the real work starts. This tier, Core idioms, is a tour of every shape C compiles into, and we begin where the machine is friendliest: integer arithmetic. Over the next few lessons you'll learn to read:

• add, subtract, multiply, and divide between registers,
• the tricks the compiler plays — a multiply or divide by a constant that becomes a shift, a division with no divide instruction at all, and a modulo that lives nowhere in the hardware,
• and how operator precedence decides the order the instructions come out in.

Same rules as the last chapter: the editor starts empty, the name is in the header, and the signature is yours to work out. Time to add two numbers.