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EarthBound Zero/RAM map: Difference between revisions

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(the checksum is figured out!)
(Redirect to merged Earthbound Beginnings RAM map)
Tag: New redirect
 
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{{rammap|game=EarthBound Zero}}
#REDIRECT [[EarthBound Beginnings/RAM map]]
 
=RAM=
 
{|border="1" cellpadding="1"
!RAM !! Purpose
|-
|0x0006 || Part of an instruction for "copy protection". $E5 on checksum failure. $00 to bypass.  "Correct"/non-hack value unknown.
|-
|0x0015 || Used for assigning area to objects?
|-
|0x0060 || HP target value for stat increase during level up
|-
|0x0611 || Looks like the first EXP byte, but changing it even mid-battle will result in insta-death.  Anti-cheat?
|-
|0x0818-B || The X and Y coordinates, stored strangely; see below
|}
 
===Coordinates===
The coordinates in RAM to not correspond to coordinates in the rest of the game.  To convert it, run this Python code (in this example, bytes $818-B are `80 19 C0 2D`):
 
<pre>
# replace with the values from the RAM
ram_x = 0x1980
ram_y = 0x2dc0
 
real_x = ((byte1 << 8) | (byte0 & 0xC0)) >> 2
real_y = ((byte3 << 8) | (byte2 & 0xC0) - 0x2000) >> 2
</pre>
 
=SRAM (save data)=
===Unknown===
* 0000-13FF: '''Unknown'''
===Checksum===
The 2-byte checksum is calculated by subtracting each byte after it (0x300 for each save, so 0x29E bytes to subtract), then running it through mod 0x10000.
Here is an example Python program that calculates it:
<pre>
def calculate_checksum(handle, base = 0x1700):
    handle.seek(base)
    checksum = int.from_bytes(handle.read(2), "little")
    calculated_checksum = 0x0
    for number in range(0x300 - 0x2):
        calculated_checksum = (calculated_checksum - int.from_bytes(handle.read(2), "little")) % 0x100 ** 2
    return calculated_checksum
calculate_checksum(open("file.sav", "rb"))
</pre>
* 1400-1401: Checksum
===Main data===
* 1402-1403: '''Unknown'''
* 1404-1407: Position
* 1408-140B: Current party members
*:Each number corresponds to an ally in [[EarthBound Zero:Ally data|Ally data]], 0 means empty and skips to the next value.
* 140C-140F: '''Unknown'''
* 1410-1411: Current money
* 1412-1414: Money in bank
* 1415-141F: '''Unknown'''
* 1420-1430: Your name (the player name, not Ninten's name)
* 1431-143F: '''Unknown'''
===Ally status===
This is documented [[#Ally state|below]].
* 1440-147F: Ninten
* 1480-14BF: Ana
* 14C0-14FF: Lloyd
* 1500-153F: Teddy
* 1540-157F: Pippi
* 1580-15BF: EVE
* 15C0-15FF: Flying Man
===Other===
* 1600-1688: '''Unknown'''
* 1689-1983: Favorite food name
* 1984-16AF: '''Unknown'''
* 16B0-16CF: Items in storage
===Unknown===
* 16D0-1FF0: Other
==Ally state==
Each ally's state is stored at a place corresponding to the character, see the above section
* 00: Unknown (unused?)
* 01: Status condition
** Bit 0: Cold
** Bit 1: Poisoned
** Bit 2: Puzzled
** Bit 3: Confused
** Bit 4: Sleeping
** Bit 5: Paralyzed
** Bit 6: Stone
** Bit 7: Unconscious (can be applied even when HP isn't at 0)
* 02: '''Unknown'''
* 03-04: Max HP
* 05-06: Max PP
* 07-08: Offense
* 09-0A: Defense
* 0B: Fight
* 0C: Speed
* 0D: Wisdom
* 0E: Strength
* 0F: Force
* 10: Level
* 11-13: Experience
* 14-15: Current HP
* 16-17: Current PP
* 18-19: '''Unknown'''
* 20-27: Items
* 28: Weapon
* 29: Coin
* 2A: Ring
* 2B: Pendant
* 30-37: Learned PSI
* 38-3E: Name
* 3F: Unknown (unused?)
{{Internal Data|game=EarthBound Zero}}

Latest revision as of 12:20, 16 April 2025

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