Routines
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7CFC: Make a teacher tell the kids to go to a certain page in their books
Used by the routines at 7D30 and F300. Makes the teacher tell the kids to turn to or answer the questions on a randomly chosen page of their books.
Input
H Teacher's character number (0xA3-0xA6)
7CFC LD DE,$F26F BC=F262 (TURN TO PAGE 123 OF YOUR BOOKS...); DE=F26F (the '123' in this message)
7CFF LD C,$62
7D01 LD B,D
7D02 CALL $61A1 A=random number
7D05 RLCA This jump (which decides between the message at F262 and the message at F29D) is performed half the time
7D06 JR C,$7D0C
7D08 LD E,$BA BC=F29D (ANSWER THE QUESTIONS ON PAGE 123 OF YOUR LOVELY TEXTBOOK); DE=F2BA (the '123' in this message)
7D0A LD C,$9D
7D0C SCF A=128-255 (random page number to insert into the message)
7D0D RRA
7D0E NOP
7D0F EX DE,HL Point HL at the slot for the 100s digit of the page number in the message
7D10 LD (HL),$2F Compute and insert the ASCII code for the 100s digit of the page number
7D12 INC (HL)
7D13 SUB $64
7D15 JR NC,$7D12
7D17 INC L Point HL at the slot for the 10s digit of the page number
7D18 ADD A,$64 Compensate for the trial subtraction of 100 above
7D1A LD (HL),$2F Compute and insert the ASCII code for the 10s digit of the page number
7D1C INC (HL)
7D1D SUB $0A
7D1F JR NC,$7D1C
7D21 INC L Point HL at the slot for the units digit of the page number
7D22 ADD A,$3A Compensate for the trial subtraction of ten above, and add an extra 0x30 (the ASCII code for '0')
7D24 LD (HL),A Insert the ASCII code for the units digit of the page number
7D25 EX DE,HL Restore the teacher's character number to H
This entry point is used by the routines at 7D30, 7D84, F300, F7E0, F800 and F9F6.
7D26 LD L,$6C Place the address of the message into bytes 0x6B and 0x6C of the character's buffer
7D28 LD (HL),B
7D29 DEC L
7D2A LD (HL),C
7D2B LD BC,$7986 Place the address of the interruptible subcommand routine at 7986 (make character speak) into bytes 0x69 and 0x6A of the character's buffer and jump to it
7D2E JR $7CF1
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