CS208 Introduction to Computer Systems
Monday, 9 October 2023

+ Next
- Intro to x86_64 assembly language
    and machine language
- Using the gdb debugger
- How do C constructs get translated into x86_64?

+ Why learn assembly language?
- to better understand C and higher-level languages
- it's cool
- to understand some vicious security problems
- to understand why garbage collection, string classes, Rust, etc. exist
- (unlikely for most of you) to become an assembly language programmer

+ Meet Compiler Explorer (godbolt.org)
- Try this

    int main() {
        int sum = 0;
        for (int k = 0; k < 10; k++) {
            sum += k * k;
        }

        return sum;
    }

+ x86_64 architecture
- registers
    - register names
    - notable: EFLAGS register
    - notable: rip register
- memory

+ A little history
- Gordon Moore
- Busicom
- Intel 4004, 8008, 8080, 8086, 80186, 80286, 80386, 80486, Pentium,...
- Book: The Microprocessor: A Biography

+ C to assembly language
- Machine language vs. assembly language
- Assembly & loading: hello.asm
- object modules
    - gcc -c
    - objdump -d
- gcc -g -Og ...

+ Lab

+ Prep for the puzzles assignment
- AT&T vs. Intel notation
    - Textbook (AT&T)
    - Jeff (AT&T)
    - Felix Cloutier (Intel)
- References
    https://www.felixcloutier.com/x86/
    https://web.stanford.edu/class/archive/cs/cs107/cs107.1224/guide/x86-64.html
- Online discussions
- Let's look at one puzzle