Routines
Prev: 47781 Up: Map Next: 47987
47890: Game Selection Menu
Used by the routines at InitialiseGame and GameMenu_Unused.
Displays the menu and waits for the control method to be chosen and the game to be started. The keys "1" to "4" choose the keyboard, the Kempston joystick, the cursor joystick and Interface II, and "0" starts the game. The menu tune is played once. The choice is held in ControlMethod. If nothing is done for a while then the hall of fame is shown.
GameMenu 47890 LD A,255 Set the last method of control that was seen to an impossible value.
47892 LD (38450),A
47895 XOR A Clear the attribute.
47896 CALL ClearLargeWindowWithAttributes Call ClearLargeWindowWithAttributes.
Read the keys that choose the control method.
GameMenu_Loop 47899 CALL DisplayMenu Draw the menu using DisplayMenu.
47902 LD DE,49641 Point DE at TitleTune.
47905 CALL PlayMusic_WaitKey Play it using PlayMusic_WaitKey, if it has not been played yet.
47908 LD A,247 Read from the keyboard;
Port Number Bit
0 1 2 3 4
247 1 2 3 4 5
47910 CALL ReadKeys
47913 LD E,A Keep the keys that are pressed in E.
47914 LD A,(38426) Fetch the method of control.
47917 BIT 0,E Jump if the key 1 is not pressed.
47919 JR Z,GameMenu_CheckKey2
47921 AND %11111001 Use method zero (keyboard).
Choose a joystick if one of those keys is pressed.
GameMenu_CheckKey2 47923 BIT 1,E Jump if the key 2 is not pressed.
47925 JR Z,GameMenu_CheckKey3
47927 AND %11111001 Use method one (Kempston joystick)...
47929 OR %00000010 Set the method to the Kempston joystick.
GameMenu_CheckKey3 47931 BIT 2,E Jump if the key 3 is not pressed.
47933 JR Z,GameMenu_CheckKey4
47935 AND %11111001 Use method two (cursor keys)...
47937 OR %00000100 Set the method to the cursor keys.
GameMenu_CheckKey4 47939 BIT 3,E Jump if the key 4 is not pressed.
47941 JR Z,GameMenu_StoreControl
47943 OR %00000110 Choose Interface II.
GameMenu_StoreControl 47945 LD (38426),A Store the method of control.
Start the game if "0" is pressed.
47948 LD A,239 Read from the keyboard;
Port Number Bit
0 1 2 3 4
239 0 9 8 7 6
47950 CALL ReadKeys
47953 AND %00000001 ...and keep the key 0.
47955 JR NZ,StartGameSequence Jump to start the game if it is pressed.
47957 LD HL,38450 Point HL at the last method of control that was seen.
47960 LD A,(38426) Fetch the method of control...
47963 CP (HL) Compare it with the last method.
47964 LD (38450),A Set LastControlMethod.
47967 CALL UpdateIdleTimer Reset the idle timer if the method has changed, or count it down, using UpdateIdleTimer.
Flash the chosen control method.
47970 LD HL,47333 Point HL at Menu_Attributes.
47973 LD A,(38426) Fetch the method of control...
47976 RRCA Move the method to bits 0 and 1.
47977 AND %00000011 Keep only bits 0 and 1.
47979 LD B,4 There are four lines for the methods of control.
47981 CALL SetFlashingAttribute Make the line for the method flash using SetFlashingAttribute.
47984 JP GameMenu_Loop Jump back to draw the menu again.
View the equivalent code in;
Prev: 47781 Up: Map Next: 47987