Instructor Notes

March 31, 2008

Programmers

• directory and all files must be writable
• apparently doesn't work with Vista?

• the behavior of the emulator is not identical to that of a real GameBoy

  • keyboard bouncing
  • window behavior
  • random program

Hello Noise assignments

Random

• demonstrates programming techniques
  • modular programming
    • standard-defs.inc
    • keypad.asm
    • print-number.asm
• subtraction using 2s complement addition
• using INC_SS, DEC_SS macros
• using shift and rotate for multiplying and dividing by powers of 2
  • use this technique to get the desired range for your random number
  • using the carry flag

Hello Angle

• lookup tables
• main loop and the timer

Programming conventions

• subroutines and macros preserve registers
• pick good label names
• use local variables whenever possible
• don't overMACROize
• ALL CAPS for macros and constants
• avoid hard-coding. From good to bad:
  • find a function, usually involving a loop, which calculates what you want
    • print-number.asm
  • make a lookup table and an indexing system to look up what you want
    • hello-angle.asm
  • hard-code --- but only for very simple examples and for trying out ideas.
    • hello-noise.asm