"# GameBoyEmulator written in Python"

This is a program to emulate the DMG Gameboy...

CPU Design: The cpu utilises a fetch-decode-execution loop style. ...An instruction is fetched from the memory at the address of the program counter.. ...The program counter is then incremented ...Instruction is decoded.. ...Instruction is executed..

CPU Registers:

REGISTER | PURPOSE | 16Bit
--- | --- | ---
A | ACCUMULATOR | AF
F | STATUS FLAGS | AF
B | GP REGISTER | BC
C | COUNTER | BC
D | GP REGISTER | DE
E | GP REGISTER | DE
H | POINTER | HL
L | POINTER | HL
SP | STACK POINTER | -
PC | PROGRAM COUNTER | -

Flags:

FLAG | BIT POS | DESC
--- | --- | ---
Z | 7 | ZERO FLAG (IF RESULT == 0: 1)
S | 6 | SUBTRACTION FLAG (IF OP == SUB: 1)
H | 5 | HALF CARRY FLAG (IF CARRY FROM BIT 3 TO 4: 1)
C | 4 | CARRY FLAG (IF CARRY FROM BIT 7: 1) [OVERFLOW]

Memory Config: - 0x000 - 0x7FFF : Program Data - 0x000 - 0x0FF : Destination Address for RTS instructions and interrupts - 0x100 - 0x14F : ROM area for storing data such as name of game - 0x150 : Starting address of user program - 0x8000 - 0x9FFF : RAM for LCD display (8KBytes VRAM) - 0xA000 - 0xBFFF : External expansion RAM - 0xC000 - 0xDFFF : Work RAM area (8KB RAM) - 0xFE00 - 0xFFFF : Internal CPU RAM - 0xFE00 - 0xFE9F : OAM-RAM (Display data for 40 objects) - 0xFF00 - 0xFF7F : Port Registers/Control Registers/Sound Registers - 0xFF80 - 0xFFFE : CPU working and stack RAM (127 bytes RAM)

Register Config: USE REGISTER ADDRESS PORT/MODE P1 0xFF00 SB 0xFF01 SC 0xFF02 DIV 0xFF04 TIMA 0xFF05 TMA 0xFF06 TAC 0xFF07 INTERRUPT FLAG IF 0xFF0F IE 0xFFFF IME ------ LCD DISPLAY LCDC 0xFF40 STAT 0xFF41 SCY 0xFF42 SCX 0xFF43 LY 0xFF44 LYC 0xFF45 DMA 0xFF46 BGP 0xFF47 OBP0 0xFF48 OBP1 0xFF49 WY 0xFF4A WX 0xFF4B OAM 0xFE00 - 0xFE9F SOUND NR X X 0xFF10 - 0xFF26 WAVEFORM RAM 0xFF30 - 0xFF3F

Subjectively, Python doesn't have a nice builtin binary library. So I'll write on myself Binary will be sorted as an 8 bit array of 1 and 0 in Big Endian:

INDEX |	7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
=====================================
VALUE | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 0

However will be displayed and interrupted (outside of class methods) as strings: "111001010"

This is because leading zeros are not stored in python and thus 00001111 becomes 1111

All functions that return a result, excluding decimal and hex conversions, will return a class of itself. If a specific bit is requested, a binary class representing that bit is returned.

This library is extended to 16 bit with the class Bin16()