Gyruss: Routine at 9AD0

9AD0: VDP read byte

Used by the routine at display_star_frame.

Input
DE	Read address

Output
A	Byte read

vdp_read_byte

9AD0

LD A,E

Set LSB of VDP address

9AD1

OUT ($BF),A

9AD3

LD A,D

9AD4

OUT ($BF),A

Set MSB of VDP address

9AD6

PUSH IX

Delay

9AD8

POP IX

9ADA

NOP

9ADB

IN A,($BE)

Read byte

9ADD

RET