Attempt to reverse engineer SNES FFV game.

The project's objective - overview through the entire game code, locate key features and document it. Of particular interest is the combat system and the behavior of monsters in battle.

http://www.gamefaqs.com/snes/588331-final-fantasy-v/faqs/30040

Game engine parts

WorldMap+Field+Script=Core C0:0000	Battle C1:0000, C2:0000	Menu C2:A000	BGFX C3:0000	SPC Engine C4:0000

Sound engine

• C4:0000 - SPC init
• C4:0004 - write to [00:1D00] 4 bytes before call:
  • 01 nn 08 0F: play music #nn
  • 02 nn 0F 88: play SFX #nn
  • 80 40 08 0F: fade-out ?
  • F0 ?? ?? ??: SPC Engine soft reset
  • F2 22 08 0F: ??

ROM information

Used ROM : Final Fantasy V (J) [T+Eng1.1_RPGe].smc

(english translation by RGPe)

No SMC 512-byte header.

ROM header (0xFFC0)

• Game title : "FINAL FANTASY 5 "
• ROM makeup byte : 21, 0b00100001, [HiROM]
• ROM type: 02
• ROM size: 0B
• SRAM size: 03
• Creator license ID code: 00 C3
• Version #: 00
• Checksum complement: 0D E0
• Checksum: F2 1F

Interrupt vectors

• NMI: 0xCEE0
• IRQ: 0xCEE4

Used tools

• IDA for snes
• no$sns debugger (http://problemkaputt.de/sns.htm)

SNES Regs : http://en.wikibooks.org/wiki/Super_NES_Programming/SNES_Hardware_Registers

http://nocash.emubase.de/fullsnes.htm

IDA and CPU M/X Flags

SNES CPU has weird flags in Native mode.

• REP #0x10 : Clear X Flag (X/Y Index registers are 16-bit)
• REP #0x20 : Clear M Flag (A register is 16-bit)
• SEP #0x10 : Set X Flag (8-bit X/Y regs)
• SEP #0x20 : Set M Flag (8-bit A register)

These settings affect instruction size and sometimes IDA 65816 module fail to analyze code.

To set those flags manually - press Alt+G to change "segment registers". CPU module will map M/X flags as m/x segment regs, so you can change it manually.

To check current segregs values press Ctrl+Space.

Asm hints

• BCC reg, imm : if ( reg < imm)
• BCS reg, imm : if ( reg >= imm )
• BMI reg : if ( reg & 0x80 ) / if ( reg >= 0x80 )
• BPL reg : if ( reg < 0x80 )