THE ULTIMATE MEGA MAN III HACKING DOCUMENT



EMULATION/ROM HACKING

NINTENDO ENTERTAINMENT SYSTEM

MEGA MAN III DATA

INCLUDES RAM ADDRESSES, HEX OFFSETS, CODE, ETC.

DATA BY RETRORAIN



PRG ROM: 16 x 16KiB

CHR ROM: 17 x  8KiB

Mapper: 4 (MMC3)

Mirroring: Horizontal



RAM ADDRESSES:

--------------



$29	Screen Page Number



This is the number of the current screen page Megaman has entered.

The first screen is 00, but when Megaman is starting the level, it is 01.



$A0	$A1	Current Weapon

--------------------------------------------

00	00	Mega Buster - Normal Megaman

01	01	Gemini Laser

02	02	Needle Cannon

03	03	Hard Knuckle

04	04	Magnet Missile

05	05	Top Spin

06	00	Search Snake

07	01	Rush Coil

08	02	Spark Shot

09	03	Rush Marine

0A	04	Shadow Blade

0B	05	Rush Jet

	80	Next



Let me explain how this works now.  $A1 is the cursor position in the inventory

screen.  And $A0 is the actual weapon.  Both of these work together.  The top-left

weapon, is 0x00, which is the Megabuster.  To the right of the Megabuster is the

Gemini Laser, which is 0x01.  Below the Megabuster is the Needle Cannon, which is

0x02.  When the cursor is on next, the value is 0x80.  The cursor value is 0x00 when

the Search Snake is selected, because that is the top-left position.  However, the

actual weapon number is 0x06.  It is actually very easy to figure out.



Megaman/Weapon Energy



0x9C is full energy, 0x81 is low energy, 0x80 is empty energy



$A2	Megaman's Energy (Health)

$A3	Gemini Laser Energy

$A4	Needle Cannon Energy

$A5	Hard Knuckle Energy

$A6	Magnet Missile Energy

$A7	Top Spin Energy

$A8	Search Snake Energy

$A9	Rush Coil Energy

$AA	Spark Shot Energy

$AB	Rush Marine Energy

$AC	Shadow Blade Energy

$AD	Rush Jet Energy



$AE	Lives



0x02 is starting lives, 0x00 is empty lives



$AF	Energy Tanks



0x00 is starting energy tanks, you start with nothing.



$B5	Weapon Fire Counter



0x00 is the starting amount.  This serves as a counter for certain weapons.  It is

reset to zero whenever a different weapon is selected.  It is the counter for the

following weapons:



Mega Buster

Needle Cannon

Top Spin

Search Snake

Shadow Blade

Rush Marine

Rush Jet



OFFSETS:

--------



Losing an E. Tank	         0x04078 - How many E. Tanks you lose when you use one.  Default is 0x01.

Retry Lives		0x3192F - Retry lives is 0x02.

Megaman's Palette	         0x3C8A9 - The 3 bytes that define Megaman's palette (0F 2C 11).

Starting Lives		0x3C90C - Starting lives is 0x02.

Losing a Life		0x3CB92 - How many lives you lose when Megaman dies.  Default is 0x01.



CODE:

-----



INITIALIZE LIVES



This is the code that sets up how many lives you start out with.

It is initialized right before the start of a level.



$C8FB:A9 02     LDA #$02

$C8FD:85 AE     STA $AE = #$00



RETRY LIVES



This is the code that is executed when you get Game Over, and you

choose to continue through CONTINUE or STAGE SELECT.  Once you get

Game Over, this is the code that will re-initialize your lives.



$991E:A9 02     LDA #$02

$9920:85 AE     STA $AE = #$00



LOSE A LIFE



This is the code that is executed when Mega Man dies, which decrements

his lives by 1.



$CB7E:A5 AE     LDA $AE = #$02

$CB80:38        SEC

$CB81:E9 01     SBC #$01

$CB83:90 2C     BCC $CBB1

$CB85:85 AE     STA $AE = #$02



LOSE AN ENERGY TANK



This is the code that is executed when you use an Energy Tank, which

decrements your Energy Tanks by 1.  It is important to note that the

game has no code to initialize Energy Tanks, since you always start

the game with 0 Energy Tanks.



$A062:A5 AF     LDA $AF = #$04

$A064:F0 37     BEQ $A09D

$A066:38        SEC

$A067:E9 01     SBC #$01

$A069:85 AF     STA $AF = #$04