Routines
Prev: 9301 Up: Map Next: 9532
9470: Game entry point
GameEntry 9470 LD HL,$FAF4 Write FAF4 to CHARS.
9473 LD ($5C36),HL
9476 LD A,$01 Write 01 to DF_SZ.
9478 LD ($5C6B),A
947B LD A,$01 Write 01 to ControlMethod.
947D LD ($5BA8),A
This entry point is used by the routines at InstructionsPrint, BestScoresPrint and StartGame.
GameEntry_0 9480 LD HL,$4000 Writes 00 to all 1800 screen buffer address locations (clears the screen).
9483 LD DE,$4001
9486 LD (HL),$00
9488 LD BC,$17FF
948B LDIR
948D LD A,$07 Write 07 to BORDCR.
948F LD ($5C48),A
9492 XOR A Set the border colour to BLACK.
9493 OUT ($FE),A
9495 LD A,$03 Write 03 to TemporaryCounter.
9497 LD ($5BBA),A
949A CALL $955A Call 955A.
949D CALL TitleScreenPrint Call TitleScreenPrint.
94A0 LD A,($5BA8) If ControlMethod is 01 jump to TitleScreenInit.
94A3 CP $01
94A5 JP Z,TitleScreenInit
94A8 LD A,($5BA8) If ControlMethod is 02 jump to Input_KempstonJoystick.
94AB CP $02
94AD JP Z,Input_KempstonJoystick
94B0 LD A,($5BA8) If ControlMethod is 03 jump to Input_ProtekJoystick.
94B3 CP $03
94B5 JP Z,Input_ProtekJoystick
94B8 LD A,($5BA8) If ControlMethod is 05 jump to Input_Interface2.
94BB CP $05
94BD JP Z,Input_Interface2
Handles selecting "1. KEYBOARD".
TitleSelectInput 94C0 LD A,$F7 Read from the keyboard;
Port Number Bit
0 1 2 3 4
F7 1 2 3 4 5
94C2 IN A,($FE)
94C4 AND %00000001 Keep only bit 0.
94C6 JP Z,InputTest_Keyboard If "1" was pressed then jump to InputTest_Keyboard.
Handles selecting "2. KEMPSTON JOYSTICK".
94C9 LD A,$F7 Read from the keyboard;
Port Number Bit
0 1 2 3 4
F7 1 2 3 4 5
94CB IN A,($FE)
94CD AND %00000010 Keep only bit 1.
94CF JP Z,InputTest_KempstonJoystick If "2" was pressed then jump to InputTest_KempstonJoystick.
Handles selecting "3. PROTEK JOYSTICK".
94D2 LD A,$F7 Read from the keyboard;
Port Number Bit
0 1 2 3 4
F7 1 2 3 4 5
94D4 IN A,($FE)
94D6 AND %00000100 Keep only bit 2.
94D8 JP Z,InputTest_ProtekJoystick If "3" was pressed then jump to InputTest_ProtekJoystick.
Handles selecting "4. INTERFACE 2".
94DB LD A,$F7 Read from the keyboard;
Port Number Bit
0 1 2 3 4
F7 1 2 3 4 5
94DD IN A,($FE)
94DF AND %00001000 Keep only bit 3.
94E1 JP Z,InputTest_Interface2 If "4" was pressed then jump to InputTest_Interface2.
Handles ... cheat codes?
CHEATCODES 94E4 LD A,$FD Read from the keyboard;
Port Number Bit
0 1 2 3 4
FD A S D F G
94E6 IN A,($FE)
94E8 AND %00000011 Keep only bits 0-1.
94EA JP Z,$992A If "A" and "S" was pressed then jump to 992A.
94ED LD A,$FD Read from the keyboard;
Port Number Bit
0 1 2 3 4
FD A S D F G
94EF IN A,($FE)
94F1 AND %00000001 Keep only bit 0.
94F3 JP Z,$9944 If "A" was pressed then jump to 9944.
Handles selecting "5. INSTRUCTIONS".
94F6 LD A,$F7 Read from the keyboard;
Port Number Bit
0 1 2 3 4
F7 1 2 3 4 5
94F8 IN A,($FE)
94FA AND %00010000 Keep only bit 4.
94FC JP Z,InstructionsPrint If "5" was pressed then jump to InstructionsPrint.
Handles selecting "6. PLAY".
94FF LD A,$EF Read from the keyboard;
Port Number Bit
0 1 2 3 4
EF 0 9 8 7 6
9501 IN A,($FE)
9503 AND %00010000 Keep only bit 4.
9505 JP Z,StartGame If "6" was pressed then jump to StartGame.
9508 LD HL,($5B99) Increment the value at RandomNumberSeed by one.
950B INC HL
950C LD ($5B99),HL
950F LD A,$1F A=1F.
9511 CP H
9512 CALL Z,ResetRandomSeed
9515 LD HL,($5BB8) Increment the value at TemporaryAddress by one.
9518 INC HL
9519 LD ($5BB8),HL
951C XOR A A=00.
951D CP H
951E JP NZ,TitleSelectInput
9521 CP L
9522 JP NZ,TitleSelectInput
9525 LD A,($5BBA) Increment the value at TemporaryCounter by one.
9528 DEC A
9529 LD ($5BBA),A
952C JP NZ,TitleSelectInput
952F JP BestScoresPrint Jump to BestScoresPrint.
Prev: 9301 Up: Map Next: 9532