Predefined Symbols table

[T KARTHIKEYAN]

RAM address for SP is the same as that of R0, wouldn't that create any error?

[Lozminda]

The short answer is, 'No.'

These are just naming conventions, which will make sense as you work through the book. The authors do this a lot, drop in stuff early that doesn't quite make sense until a couple of chapters later.

All will be revealed, have faith !

Lozminda

[WBahn]

Only if you try to use them for different things at the same time.

R0 through R15 are just names used to refer to the first 16 words in RAM for the purpose of making our assembly language programs easier to read for humans. The same for the beginning of screen memory and the keyboard.

As we move up the tool chain, we choose to dedicate some of those early memory addresses to specific uses and we choose to use names that are descriptive of those uses. In doing so, we are also making an agreement with ourselves that we won't use those same memory locations for anything else, regardless of what we call it.