Logo file

From NeoGeo Development Wiki
Revision as of 00:27, 14 May 2018 by Hpman (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
CDZ default loading screen.
KOF 96 custom loading screen (LOGO_E.PRG).

LOGO files are optional files used to create custom CD loading screens.

The system ROM automatically loads one of the following files according to the console's nationality setting, if present in the CD's root:

  • LOGO_E.PRG for European nationality.
  • LOGO_U.PRG for US nationality.
  • LOGO_J.PRG for Japanese nationality.

The files must not be larger than ?? bytes. (KOF '99 uses 16.3KB files)

File format

Size Description
Word Flags
Longword Data type
Longword Data pointer
Longword Data type
Longword Data pointer
Longword 0xFFFFFFFF terminator
? Data previously pointed to...

The first word represents flags:

  • Bit 0: If set, do not draw the default 'NOW LOADING please wait' graphic (see picture top right).
  • Bit 1: If set, no progress bar is drawn.
  • Bit 2: If set, no animation is drawn.

No other bits seem to be checked by the system ROM.

The rest of the file's contents are "data type - pointer" longword pairs. The type codes used must be sorted in an ascending order. The file is terminated with a $FFFFFFFF type code. The valid type codes are:

  • 1: Fix tiles
  • 2: Palette
  • 3: Tile map
  • 4: Animation map

The pointer values are absolute, starting from $120000.

Fix tiles data format

  • Offset (longword). Example: $4000 = start at tile #512
  • Size (longword). Example: $2000 = load 256 tiles
  • Tile data...

Like the regular fix graphics format, but byteswapped.

Palette data format

Note: The default progress bar seems to use palette 0, be careful not to overwrite it. Remember that fix tiles can only use the 16 first palettes.

Map data format

All values are words.

  • Start fix map address ($7102 is good).
  • Width in tiles.
  • Height in tiles.
  • Fix tilemap data as found in VRAM...

Note: Mapping is done from left to right, top to bottom.

Animation map data format

All values are words.

  • Start fix map address ($7102 is good).
  • Width in tiles.
  • Height in tiles.
  • Number of frames in animation.
  • Animation speed (in frames).
  • Fix tilemap data as found in VRAM...

Using LOGO files for in-game loading

By default the system ROM will always use the initial LOGO file during in game loading sequences. It is possible to change this by loading new data over the buffered LOGO file data at $120000. How this gets loaded is not yet confirmed but its suspected that games request the data to be loaded as it would any other data given there is not need for 'LOGO' to be in the file name in this situation. It may also be possible the system ROM looks out for data being loaded into this region before drawing.

The ability to change the default progress bar (handled by the system ROM) is also available. The system ROM places the start address of its code to handle progress bar drawing at $11C80C. This code is then always called via 'MOVEA.L 0x11C80C,A0', 'JSR(A0)'. To use a custom progress bar simply place the start address of your custom progress bar code at $11C80C. Current progress bar state is held at address $10F691. Your code should handle all elements of drawing the progress bar.

It appears games plant their custom progress bar code into the default LOGO file as well as any further files that get loaded to this range. Below is the routine used by Samurai Shodown IV as seen in file 'JL_ST1.PRG' once in RAM. The main game program code places 0x120086 to $11C80C

120086  4EF9 0012 4AD0             JMP      0x124AD0
124AD0  4DF9 003C 0000             LEA      0x3C0000,A6
124AD6  41F9 0012 4B00             LEA      0x124B00,A0
124ADC  1239 0010 F691             MOVE.B   0x10F691,D1
124AE2  0241 00F0                  ANDI.W   #0xF0,D1
124AE6  D0C1                       ADDA.W   D1,A0
124AE8  203C 719B A200             MOVE.L   #0x719BA200,D0
124AEE  7E0F                       MOVEQ    #0xF,D7
124AF0  1018                       MOVE.B   (A0)+,D0
124AF2  2C80                       MOVE.L   D0,(A6)
124AF4  0680 0020 0000             ADDI.L   #0x200000,D0
124AFA  51CF FFF4                  DBF      D7,*-0xA [0xC00422]
124AFE  4E75                       RTS