Skool Daze: Routine at 7CD0

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