Note that most functions in this game are essentially written in a higher-level computer language than 6502. By using a jump table, more complex operations are able to be identified by single hex codes. These functions are prefaced by "20 09 E5 ## ##" (JSR $E509) and terminated by the operation "CF". (## ## indicates how many memory spaces need to be dedicated to the new function, written as an inverse. A function that requires no new memory space will say "00 00", while one that requires 16 spaces will say "F0 FF".
Sometimes one of these functions will jump to a subroutine which is written "normally" (without upper-level operations). These routines are prefaced by "20 E3 E2 ## ## ##" (JSR $E2E3).
A list of these operations is located here. This same system seems to be used by the other MMC5 Koei games.
Page E0 ($A000-$BFFF)
ROM location: 0x00010-0x0200F
Prints graphic (5) to tile coordinates (1),(3)
Checks if City 1 (1/2) can sail to City 2 (3/4). (5) = whether sea control matters
Checks if it's safe to sail from City (1/2). Returns 0 if city is landlocked or sea is controlled by a hostile nation; otherwise, returns 1.
Checks if officer (1/2) is player-controlled.
Checks if commander of city (1/2) is player-controlled.
Checks if city (1/2) is adjacent to city (3/4) [by either land or sea]
Check if nation (3/4) exists. (Parameter 1/2 serves no function?)
Verifies checksum when loading game(?)
Erase sprites #(1) to #(1)+(3)
Determines which nation has control of sea (1/2).
00 = Baltic, 01 = North, 02 = Atlantic, 03 = Mediterranean
Page E1 ($8000-$9FFF)
ROM location: 0x02010-0x0400F
Page E2 ($A000-$BFFF)
ROM location: 0x04010-0x0600F
Page E3 ($A000-$BFFF)
ROM location: 0x06010-0x0800F
Page E4 ($A000-$BFFF)
ROM location: 0x08010-0x0A00F
Page E5 ($A000-$BFFF)
ROM location: 0x0A010-0x0C00F
Page E6 ($A000-$BFFF)
ROM location: 0x0C010-0x0E00F
Page E7 ($A000-$BFFF)
ROM location: 0x0E010-0x1000F
Page E8 ($A000-$BFFF)
ROM location: 0x10010-0x1200F
Contains functions pertaining to CPU actions during the city phase.
Main function for all CPU city actions.
A8E4 AA D1 7C / Push $7CD1/$7CD2 to stack / (+2) Active city A8E7 E9 DB BA 02 / Run function $BADB / (-2)
Page FA ($A000-$BFFF)
Table of Nations
$A004 + #$0A x (Nation code) = Beginning of nation data starting with name and ending with hidden stat.
Table of Cities
$A09A + #$20 x (City code) = Beginning of city data starting with name and ending with hidden stat.
Table of Officers
$A650 + #$11 x (Officer code) = Beginning of officer data starting with name and ending with hidden stat.
See Notes for more detail on hidden stats.
Page FE ($C000-$DFFF)
ROM location: 0x3C010-0x3E00F
Main game loop. Executes all game functions then waits until interrupt
C008 61 / Push #$01 to stack / (+2) C009 E9 6F CF 02 / Run function $CF6F / (-2) C00D 8D 1F / Push #$1F to stack / (+2) C00F 60 / Push #$00 to stack / (+2) C010 E9 C9 CF 04 / Run function $CFC9 / (-4) C014 8D 14 / Push #$14 to stack / (+2) C016 67 / Push #$07 to stack / (+2) C017 E9 BC C3 04 / Run function $C3BC / (-4) C01B AA 00 60 / Push $6000/$6001 to stack / (+2) C01E 8E 16 DF / Push #$DF16 to stack / (+2) C021 E9 27 C6 04 / Run function $C627 / (-4) C025 61 / Push #$01 to stack / (+2) C026 64 / Push #$04 to stack / (+2) C027 E9 1E EF 04 / Run function $EF1E / (-4) C02B B3 / Push M8 to stack / (+2) C02C 8E 22 DF / Push #$DF22 to stack / (+2) C02F E9 27 C6 04 / Run function $C627 / (-4) C033 62 / Push #$02 to stack / (+2) C034 64 / Push #$04 to stack / (+2) C035 E9 1E EF 04 / Run function $EF1E / (-4) C039 B3 / Push M8 to stack / (+2) C03A 8E 2A DF / Push #$DF2A to stack / (+2) C03D E9 27 C6 04 / Run function $C627 / (-4) C041 D6 41 C0 / Jump to $C041 / Stall until interrupt C042 CF / Exit
Officer gains 1 EXP.
Parameter 1/2 = Officer address
C237 0C / Store parameter 1/2 to M8 / Officer address C238 76 / Add #$06 to M8 / Officer exp address C239 2B / Store M8 to storage 1/2 C23A 0B / Store storage 1/2 to M8 C23B B3 / Push M8 to stack / (+2) C23C D3 / Replace M8 with 1-byte value / Officer exp (old) C23D D0 / Increment M8 / +1 exp C23E D4 / Pull 2 meta, store $0008 / (-2) Update exp C23F 0B / Store meta 01/02 to M8 C240 D3 / Replace M8 with 1-byte val / Officer exp (new) C241 8B 64 / Store #$64 to MC C243 C9 / Check if M8 >= MC / Check if 100+ C244 D8 4F C2 / Jump to $C24F if not / Exit C247 3B / Push storage 1/2 to stack / (+2) C248 40 / Store #$00 to M8 C249 D4 / Pull 2 meta, store $0008 / (-2) Roll EXP over to 00 C24A 3C / Push params 1/2 to stack / (+2) C24B E9 D6 C1 02 / Run function $C1D6 / (-2) Officer Levels Up C24F CF / Exit
Page FF ($E000-$FFFF)
Prep for assembly functions.
Prep for higher-level functions.