FF7/Battle and growth data

Kernel.bin section 3

This file contains a bunch of information about character growth and battles. Table below explains it all (credits go to Terence F. for this).

General data layout

Table 1: Section 3 of kernel.bin description

Offset	Length	Description
0x0000	56 bytes	Character data: Cloud (see below)
0x0038	56 bytes	Character data: Barret
0x0070	56 bytes	Character data: Tifa
0x00A8	56 bytes	Character data: Aeris
0x00E0	56 bytes	Character data: Red XIII
0x0118	56 bytes	Character data: Yuffie
0x0150	56 bytes	Character data: Cait Sith
0x0188	56 bytes	Character data: Vincent
0x01C0	56 bytes	Character data: Cid
0x01F8	12 x 1 byte	Random bonus to primary stats
0x0204	12 x 1 byte	Random bonus % to HP
0x0210	12 x 1 byte	Random bonus % to MP
0x021C	37 x 16 bytes	Primary stat curve 0 - 36 (see below)
0x046C	9 x 16 bytes	HP stat curve 37 - 45 (Base * 40)
0x04FC	9 x 16 bytes	MP stat curve 46 - 54 (Base * 2)
0x058C	9 x 16 bytes	EXP stat curve 55 - 63 (Gradient is quadratic, no Base)
0x61C	1508 bytes	Character AI data (see below)
0xC00	540 bytes	FF padding
0xE1C	256 bytes	Random number look-up table (all numbers from 0-255 are here)
0xF1C	64 bytes	Scene.bin look-up table (see below)
0xF5C	56 bytes	Spell order from Magic menu in battles (see below)

Character data record

Offset	Length	Function
0x00	1 byte	Strength Level-Up Curve
0x01	1 byte	Vitality Level-Up Curve
0x02	1 byte	Magic Level-Up Curve
0x03	1 byte	Spirit Level-Up Curve
0x04	1 byte	Dexterity Level-Up Curve
0x05	1 byte	Luck Level-Up Curve
0x06	1 byte	HP Level-Up Curve
0x07	1 byte	MP Level-Up Curve
0x08	1 byte	Experience Level-Up Curve
0x09	1 byte	FF (padding)
0x0A	1 byte	Starting Level
0x0B	1 byte	FF (padding)
0x0C	1 byte	Limit Command 1-1
0x0D	1 byte	Limit Command 1-2
0x0E	1 byte	Limit Command 1-3 (UNUSED)
0x0F	1 byte	Limit Command 2-1
0x10	1 byte	Limit Command 2-2
0x11	1 byte	Limit Command 2-3 (UNUSED)
0x12	1 byte	Limit Command 3-1
0x13	1 byte	Limit Command 3-2
0x14	1 byte	Limit Command 3-3 (UNUSED)
0x15	1 byte	Limit Command 4-1
0x16	1 byte	Limit Command 4-2 (UNUSED)
0x17	1 byte	Limit Command 4-3 (UNUSED)
0x18	2 bytes	Kills required for Limit Level 2
0x1A	2 bytes	Kills required for Limit Level 3
0x1C	2 bytes	Uses required for Limit 1-2
0x1E	2 bytes	Uses required for Limit 1-3 (UNUSED)
0x20	2 bytes	Uses required for Limit 2-2
0x22	2 bytes	Uses required for Limit 2-3 (UNUSED)
0x24	2 bytes	Uses required for Limit 3-2
0x26	2 bytes	Uses required for Limit 3-3 (UNUSED)
0x28	4 bytes	HP Divisor for Limit Level 1
0x2C	4 bytes	HP Divisor for Limit Level 2
0x30	4 bytes	HP Divisor for Limit Level 3
0x34	4 bytes	HP Divisor for Limit Level 4

Stat curve record

Each entry is 16 bytes long and contains eight pairs of Gradients and Bases (1 byte each) for eight different level groups:

2-11   12-21   22-31   32-41   42-51   52-61   62-81   82-99

The general formula for primary stats to follow is:

Stat Difference = Rnd(1..8) + Base + Floor(Gradient * [Level Attained] / 100) - Current Stat

This difference is capped at 11 and the value located at &[0x01F8 + Stat Difference] is added to that Stat.

HP and MP use a similar system, but a different formula:

HP Baseline = Base * 40 +  (Level - 1) * Gradient
MP Baseline = Base * 40 + [(Level - 1) * Gradient / 10]

Difference = Rnd(1..8) + [100 * Baseline / Current Stat] - 100

In the above formulas, Base is a signed byte (between -128 and 127) so Base * 40 can range between -5120 and 5080.
Again, this difference is capped at 11 and the appropriate points are increased by (Base is now treated as an unsigned byte):

(&[0x204 + Difference] / 100) * Base for HP
(&[0x210 + Difference] / 100) * [Level * Gradient / 10] - [(Level - 1) * Gradient / 10] for MP

where &[x] is the value located at the address of this section

The Experience level curves are 16 bytes long, although only eight bytes of each are used. Experience is calculated on a need-to-level basis. This means that the total Experience needed for each character to reach the next level is calculated and stored in memory.

Needed XP = [Mod * ((Lvl-1) ^ 2) / 10]

Where Mod is the value of the byte at the point in the curve based on the level to attain. So with a Mod of 70, to get to level 13 from level 12, a character would need:

70 * ((13-1) ^ 2) /10 
70 * (144 / 10)
70 * 14.4
1008 additional XP

The savemap contains information about the needed XP to get to the next level for each character so it can be assumed that the game only performs this calculation at level up and changes the needed XP stat accordingly and compares that against the total XP the character has to determine when the next level occurs.
To calculate the total XP needed for a given level:

XP = 0
For I = 1 to Lvl-1
  XP = XP + [Mod * (I ^ 2) / 10]
Next I

Remember, the Mod will need to be adjusted to the character and level group each time I increments.

Character AI data

Section contains 24-byte header representing 2-bytes per script block (1 per character?). Each number is an offset from the beginning of this block to the actual AI data. Each script block follows the same AI data found in the Battle Scenes.

Scene.bin Look-up file

As you may know, scene.bin file is divided into banks or sections. There are 33 total sections, and each one is 8192 long. Each section contains 5 - 16 GZipped files (scenes), based on their length. Since each section of scene.bin must be 8192 bytes, altering a scene may cause it to be necessary to place it in the next section. This look-up table contains data about the starting scene in each section:

00 0C 12 19 21 27 2D ...

Which means:

Section 1 contains scenes 0x00 - 0x0B = 12 files
Section 2 contains scenes 0x0C - 0x11 = 6 files
Section 3 contains scenes 0x12 - 0x18 = 7 files
... and so on.

Every time you modify scene.bin file you must also keep this table updated or you'll end with VERY random encounters (wrong battles in wrong places). You can use SceneFix program, which'll update the table for you.

Magic Order

This segment of data tells the game in what order to load the attacks into which Magic section. There are four Magic sections: Restore, Attack, Indirect, and Special. The first three can be reorganized in the battle's magic menu. When the first 56 attacks are loaded, these bytes tell the game which section and what order to be loaded in:

AAA:BBBBB
AAA - Section
BBBBB - Index within section of attack loaded

The Magic menu will only display sections 0 - 3 (Summons are section 4, E.Skills are section 5, etc.). The sections are then displayed sequentially in the field magic menu and in the order specified in the battle menu.

Eg: The fourth attack in Attack data is Regen. The fourth byte in this data segment is 08. This means load Regen into section 0 at position 8.

NOTES:

• If a value is repeated, that attack will override the previous listing.
• The final two bytes are NULL (0xFF) so the game moves the Attack pointer ahead to load the summon attacks.