Contact Sam Cruise: Routine at 28616

28616: Randomly select a message number

Used by the routine at 28357. Returns with a randomly chosen message number (different from the last one used) in A. On entry, A holds 197 or 198 depending on the type of message required: 197 for a person or group of people, 198 for a verb.

Input
A	197 or 198

28616

LD C,A

Point BC at the relevant last used message number (see 28613)

28617

LD B,111

28619

LD A,(BC)

E=last used message number (8-15, 16-23)

28620

LD E,A

28621

AND 248

Discard bits 0-2

28623

LD D,A

D=8 or 16

28624

CALL 61823

Get a random number in A

28627

AND 7

A=message number (8-15, 16-23)

28629

ADD A,D

28630

CP E

Is this the same message number as last time?

28631

JR Z,28624

Jump back to try again if so

28633

LD (BC),A

Store the randomly chosen message number for comparison next time

28634

RET