Samurai Shodown! Pocket Fighting Series

Samurai Shodown! Pocket Fighting Series
Also known as: Samurai Spirits! (JP) Developer: Saurus Publisher: SNK Platform: Neo Geo Pocket Released in JP: 1998 Released in US: 1998 Released in EU: 1998 This game has hidden development-related text. This game has debugging material.

Samurai Shodown! Pocket Fighting Series is a fighting game on the Neo Geo Pocket, based on Samurai Shodown 4, which includes bonus character, Shiki, from Samurai Shodown 64.

Debug Menu

Functionally identical to the one in Baseball Stars (Neo Geo Pocket), except the initial message doesn't show up anymore, and neither do some debug display variables at the top right corner. These might just be rendering issues.

All its code is contained in segment 0x250000, starting with two pointers to unreferenced functions 0x25000d and 0x250024. There's also an additional subroutine at 0x250018 that jumps to BIOS function 0xff1800, which seems to just reset the console.

Restore this menu with the following patch:

0xd6 = 1b 00 ff 24
0x248 = 1b 10 ff 24
0x4ff00 = 1d 16 06 20 1d 0d 00 25 1b da 00 20
0x4ff10 = c1 d4 6a 3f 00 6e 04 1d 96 5c 20 1d 24 00 25 1b 4c 02 20

The patch introduces some trampolines so that unreferenced debug functions are called as part of the main game loop, with initialization at 0x2000d6, and interaction at 0x200248:

002000d6 1b 00 ff 24     jp         LAB_0024ff00

                     LAB_0024ff00
                     XREF[1]: entry:002000d6(j)
0024ff00 1d 16 06 20     call       FUN_00200616
0024ff04 1d 0d 00 25     call       FUN_0025000d
0024ff08 1b da 00 20     jp         LAB_002000da

00200248 1b 10 ff 24     jp         LAB_0024ff10

                     LAB_0024ff10
                     XREF[1]: entry:00200248(j)
0024ff10 c1 d4 6a        cp         (w_debug_init),0x0 ; avoid passing inputs to in-game screen handlers via function do_screen
         3f 00
0024ff15 6e 04           jr         NZ/NE,LAB_0024ff1b
0024ff17 1d 96 5c 20     call       do_screen
                     LAB_0024ff1b
                     XREF[1]: 0024ff15(j)
0024ff1b 1d 24 00 25     call       FUN_00250024
0024ff1f 1b 4c 02 20     jp         LAB_0020024c

Press Debugger (D) button + Option (C) button to bring up the menu.