Everyone's A Wally: Routine at A921

A921: Set the zero flag if the player is the current one

Used by the routines at A92C, AA30, B288 and E79B.

Input
IY	Pointer to player buffer.

A921

PUSH IY

Copy the pointer to HL.

A923

POP HL

A924

LD DE,($B09D)

Subtract the current base pointer to the buffer.

A928

AND A

A929

SBC HL,DE

A92B

RET

Return, with the zero flag set if the pointers match.