Routines
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E79B: Handler: Change Characters
Used by the routine at GameLoop.
Handler_ChangeCharacters E79B LD A,$F7 Read from the keyboard;
Port Number Bit
0 1 2 3 4
F7 1 2 3 4 5
E79D IN A,($FE)
E79F OR %11100000 Set bits 5-7.
E7A1 XOR %11111111 Return if no keys have been pressed.
E7A3 RET Z
Fetch room ID for the current character.
E7A4 LD B,(IY+$0F) B=*IY+0F.
E7A7 PUSH IY Stash the character pointer in IY on the stack.
Loop through the port bits and correlate them with the base character reference in IY.
This associates each character with a keypress.
Key Character
01 Wally
02 Wilma
03 Tom
04 Dick
05 Harry
E7A9 LD IY,$BC67 IY=FrameId_Wally.
ChangeCharacters_WhichCharacter_Loop E7AD RRCA Rotate A right once.
E7AE JR C,ChangeCharacters_CheckRoom If this key has been pressed, jump to ChangeCharacters_CheckRoom.
The character data is "interlaced" hence we can increment to point to the next character in the sequence.
E7B0 INC IY Increment IY by one.
E7B2 JR ChangeCharacters_WhichCharacter_Loop Jump to ChangeCharacters_WhichCharacter_Loop.
Check if the current character is in the same room as the selected character.
ChangeCharacters_CheckRoom E7B4 LD A,(IY+$0F) A=*IY+0F.
E7B7 CP B If this is the same room, jump to ChangeCharacters_Process.
E7B8 JR Z,ChangeCharacters_Process
If the character is elsewhere, print where they are to the screen.
E7BA CALL Handler_DisplayCharacterLocation Call Handler_DisplayCharacterLocation.
Restore the current character pointer to IY and return.
ChangeCharacters_Return E7BD POP IY Restore the character pointer in IY from the stack.
E7BF RET Return.
The chosen character is in the same room as the current character, so begin to action the request.
ChangeCharacters_Process E7C0 CALL Character_Active Call Character_Active.
E7C3 JR Z,ChangeCharacters_Return If the selected character is the current character, jump to ChangeCharacters_Return.
E7C5 LD ($B09D),IY Write IY to *CurrentCharacter.
E7C9 POP IY Restore IY from the stack.
E7CB LD A,B A=B.
E7CC CALL $AC69 Call AC69.
E7CF LD A,(HL) A=*HL.
E7D0 LD (IY+$69),A Write A to IY+69.
E7D3 INC HL Increment HL by one.
E7D4 LD A,(HL) A=*HL.
E7D5 LD (IY+$64),A Write A to IY+64.
E7D8 INC HL Increment HL by one.
E7D9 LD A,(HL) A=*HL.
E7DA LD (IY+$73),A Write A to IY+73.
E7DD LD (IY+$6E),$05 Write 05 to IY+6E.
E7E1 LD IY,($B09D) IY=*CurrentCharacter.
Update the banner to show the updated character name.
E7E5 CALL PrintBanner Call PrintBanner.
E7E8 RET Return.
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