|
Routines |
| Prev: 6022 | Up: Map | Next: 6047 |
|
Copied to 5B80 by Copy_Loader. After the game has been loaded to 5E80 this moves it down and decrypts it from the top with RRD, then starts the game at StartGame.
|
||||
|
Set up the stack and move the game down into place.
|
||||
| Decrypt_Game | 602E | LD SP,$FE00 | Set the stack pointer to FE00. | |
| 6031 | DI | Disable interrupts. | ||
| 6032 | CALL $FC00 | Call FC00 to move the game down to 5C80. | ||
|
Decrypt every byte from FA00 down to 5C01.
|
||||
| 6035 | LD HL,$FA00 | Set the start address in HL to FA00. | ||
| 6038 | XOR A | Clear the nibble carried between bytes in A. | ||
| 6039 | LD BC,$9E00 | Set the byte count in BC to 9E00. | ||
|
Start rotating each byte through A to decrypt it.
|
||||
| Decrypt_Game_Loop | 603C | RRD | Rotate the nibbles of the current byte through A. | |
| 603E | DEC HL | Move down to the previous byte. | ||
| 603F | DEC C | Decrease the low byte of the counter by one and loop back to Decrypt_Game_Loop until none remain. | ||
| 6040 | JR NZ,Decrypt_Game_Loop | |||
| 6042 | DJNZ Decrypt_Game_Loop | Decrease the high byte of the counter by one and loop back to Decrypt_Game_Loop until every byte has been decrypted. | ||
| 6044 | JP $5C80 | Jump to StartGame. | ||
| Prev: 6022 | Up: Map | Next: 6047 |