Skool Daze: Routine at F400

F400: Make a teacher conduct a question-and-answer session

Used by the routine at F300. Controls the teacher during a question-and-answer session, but hands control back to the routine at F300 if ERIC goes missing.

Input
H	Teacher's character number (0xA3-0xA6)

F400

LD L,$64

Replace the primary command routine address in bytes 0x63 and 0x64 of the teacher's buffer with F400 (this routine)

F402

LD (HL),$F4

F404

CALL $7CD0

Is ERIC in the room?

F407

JR Z,$F410

Jump if so

ERIC is absent.

F409

LD L,$64

Replace the address of this primary command routine in bytes 0x63 and 0x64 of the teacher's buffer with that of F300

F40B

LD (HL),$F3

F40D

JP $F305

Make EINSTEIN tell the teacher that ERIC is not in class

ERIC is in class, so fire off a question and answer.

F410

CALL $7A32

Prepare a question and the answer

F413

LD BC,$7986

Hand over control to the routine at 7986, making the teacher ask the question

F416

CALL $7CF1

Control returns here when the teacher has finished asking the question.

F419

EX DE,HL

Transfer the teacher's character number to D

F41A

CALL $7CB6

Make the teacher wait for EINSTEIN to answer the question

F41D

JR $F404