Heroes of Karn: Routine at B560

B560: Validate If Item Is Present

Used by the routines at Parser_CheckObjectIsHere, CheckActiveScenicEvents, Handler_ScenicEvents, MovePlayerToRoom, Handler_ChangeRoom, Handler_ShowNewRoom and Action_Help.

Get Object Location.

Input
A	Object ID

Output
F	Z flag set if the object is available

ValidateItemPresent

B560

PUSH HL

Stash HL and DE on the stack.

B561

PUSH DE

B562

LD E,A

HL=Table_ItemLocations + the object ID.

B563

LD D,$00

B565

LD HL,$AD76

B568

ADD HL,DE

B569

LD A,($AECD)

A=*CurrentRoom.

Jump to Handler_Objects_Return if the object/ event table states that it's located in *the current room. Note also sets/ unsets the Z flag accordingly.

B56C

CP (HL)

Jump to Handler_Objects_Return if the object is in the current room.

B56D

JR Z,Handler_Objects_Return

Check the players inventory, as an object can still be used if it's being held.

B56F

LD A,$01

Lastly, set the Z flag if the item is in the players inventory.

B571

CP (HL)

Housekeeping; restore DE and HL to their previous values.

Handler_Objects_Return

B572

POP DE

Restore DE and HL from the stack.

B573

POP HL

B574

RET

Return.

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