I was feeling a bit like the Petunia and thought "Oh no, not again." :-) One of the annoyances of embedded programming can be having the wheel re-invented a zillion times. I was pleased to see that the author was just describing good software architecture that creates portable code on top of an environment specific library.
For doing 'bare metal' embedded work in C you need the crt0 which is the weirdly named C startup code that satisfies the assumption the C compiler made when it compiled your code. And a set of primitives to do what the i/o drivers of an operating system would have been doing for you. And voila, your C program runs on 'bare metal.'
Another good topic associated with this is setting up hooks to make STDIN and STDOUT work for your particular setup, so that when you type printf() it just automagically works.
This will also then introduce you to the concept of a basic input/output system or BIOS which exports those primitives. Then you can take that code in flash/eprom and load a binary compilation into memory and start it and now you've got a monitor or a primitive one application at a time OS like CP/M or DOS.
Its a fun road for students who really want to understand computer systems to go down.
For doing 'bare metal' embedded work in C you need the crt0 which is the weirdly named C startup code that satisfies the assumption the C compiler made when it compiled your code. And a set of primitives to do what the i/o drivers of an operating system would have been doing for you. And voila, your C program runs on 'bare metal.'
Another good topic associated with this is setting up hooks to make STDIN and STDOUT work for your particular setup, so that when you type printf() it just automagically works.
This will also then introduce you to the concept of a basic input/output system or BIOS which exports those primitives. Then you can take that code in flash/eprom and load a binary compilation into memory and start it and now you've got a monitor or a primitive one application at a time OS like CP/M or DOS.
Its a fun road for students who really want to understand computer systems to go down.