Instructor Notes

February 13, 2008

quote

"The best way to predict the future is to invent it." (Alan Kay, 1971)

Z80 assembly applied intro

review

• new opcodes: JP, JR, PUSH, POP, CALL, RET
• the flag register (pg. 76 Z80 user's guide).
  • conditional: Z flag, C flag

  • opcode: CP: CP C --> A - C

• addressing modes: direct, indirect

Z80 example

• example: loop for time delay
  • Anthrax line 1704 example
  • expand to 16 bit loop

special commands for the assembler

• ;
• include
• section "name",HOME[location]
• section "name",BSS[location]
• db
• EQU
• reference

GameBoy Architecture

get it all from gbspec.txt and gbhw.inc

Hello Video

• gbspec lines 611-788
• tiles, sprites
• window is 256x256 pixels = 32x32 tiles or sprites, screen is 160x144 pixels
• Tiles are ASCII character set, 8x8 pixels each starting at $8000 (Tile pattern table a.k.a. tile data table)
• Load tiles numbers into video memory, starting at $9800 (background tile map).
  • We do not load the tiles themselves. Just the numbers.
  • tiles are 16 bytes each, numbers are 1 byte each
  • we cannot write to the background tile map or the title pattern table except between screen refreshes

Hello I/O

• gbspec lines 1016 to end of document
• I/O registers from $FF00 to $FF4B, and $FFFF
  • timer, read joy pad, serial data, sound, video modes, window placement, etc.

Hello World

• walkthru of "hello world" code

IDE

download and install

• editor
• assembler
• emulator
• "hello world" test program

for another class

• instruction types
• more on addressing modes (TRS-80 book page 41 chap 3)
• interrupts

additional resources

• students need links and references for supporting materials to read outside of class