CS452 F23 Lecture Notes
Lecture 01 - 07 Sep 2023

• emphasis is on experience with software that interacts with the real world
• data acquisition, model/control physical world, communication

• small operating system, plus train control application
• start from scratch, get a better understanding of things you may take for granted
  • booting
  • device interaction
  • memory
  • timing
  • threading and concurrency

• design flexibility in assignments
• you define and implement a project

• new serial hats
• new boot proceedure

• A0: getting started
• K1-K4: build your kernel
• TC1-TC2: train control application

• assignments: 60%
• project: 10%
• final: 30%

• very simple, does console input/output using channel 1
• use it to try the dev/test process

• cross-compiler and other usual tools (linker, readelf, etc)
• if dev on linux.student.cs.uwaterloo.ca, tools are pre-installed in /u/cs452/public/xdev/bin
• if dev on your laptop, course webpage has instructions for installing a cross-compiler and tools there

• no operating system, no libraries (including libc)

• at runtime, program will have code, data, stack (no heap)
• build process creates ELF file
  • text, data, bss sections
  • start of the text section is the entry point
• img file is produced from ELF - includes text and data (not bss)
  • bss variables need to be initialized by the program

• can’t rely on underlying OS to provide services, like I/O, memory allocation
• SIMD instructions rely on MMU, which is disabled
• options:
  • don’t use libc (like iotest)
  • use only non-problematic bits of libc (see check in iotest Makefile)

• bring printed hard copy to class

polling loop, checking track state, clock, user input

  for (;;) {
    if (c1) f1();
    if (c2) f2();
    ...
  }