Contact Sam Cruise: Routine at 6FC8

6FC8: Randomly select a message number

Used by the routine at 6EC5. Returns with a randomly chosen message number (different from the last one used) in A. On entry, A holds 0xC5 or 0xC6 depending on the type of message required: 0xC5 for a person or group of people, 0xC6 for a verb.

Input
A	0xC5 or 0xC6

6FC8

LD C,A

Point BC at the relevant last used message number (see 6FC5)

6FC9

LD B,$6F

6FCB

LD A,(BC)

E=last used message number (0x08-0x0F, 0x10-0x17)

6FCC

LD E,A

6FCD

AND $F8

Discard bits 0-2

6FCF

LD D,A

D=0x08 or 0x10

6FD0

CALL $F17F

Get a random number in A

6FD3

AND $07

A=message number (0x08-0x0F, 0x10-0x17)

6FD5

ADD A,D

6FD6

CP E

Is this the same message number as last time?

6FD7

JR Z,$6FD0

Jump back to try again if so

6FD9

LD (BC),A

Store the randomly chosen message number for comparison next time

6FDA

RET