Display_Option ($F835)

This routine displays the player or game option string, along with the current value for that option. The A-register contains the value of the option, while the Y-register points to a block of the following form:

rel y, rel x, ( for value )
rel y, rel x, ( for option string)
option string,
0x80

ENTRY:

DP = $D0

A-reg=the option value.

Y-reg points to the string block.

EXIT:

D-reg, U-reg, X-reg trashed

Source