| Routines

7CD0: Check whether ERIC and EINSTEIN are in class

Used by the routines at F300 and F400. If EINSTEIN is in class, this routine returns to the caller with the zero flag set if and only if ERIC is present too. If EINSTEIN is not yet sitting down in class, it makes the teacher wait until he shows up.
Input
H | Teacher's character number (0xA3-0xA6)
7CD0 | LD A,($A960) | A=EINSTEIN's animatory state
7CD3 | CP $15 | 0x15=EINSTEIN sitting in a chair
7CD5 | JP Z,$79D4 | Jump if EINSTEIN is sitting in a chair
7CD8 | POP DE | Place the address of the instruction that called this routine into bytes 0x63 and 0x64 of the teacher's buffer, so that control of the teacher remains in this routine until EINSTEIN is seated
7CD9 | LD L,$63
7CDB | LD A,E
7CDC | SUB $03
7CDE | LD (HL),A
7CDF | RET |