Routines
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54476: Count Objects In Location
Used by the routines at ProcessLocationTokenDisplay, PrintObjectList, PrintFormattedObjectList and 56629.
Input
A Location ID (or 255 for current character location)
Output
A Count of visible objects found in the specified location
CountObjectsInLocation 54476 PUSH IX Stash IX, IY, HL and BC on the stack.
54478 PUSH IY
54480 PUSH HL
54481 PUSH BC
54482 CALL AdjustObjectTableForSum Call AdjustObjectTableForSum to set up the object table pointer.
54485 LD B,0 Initialise the object counter in B to zero.
54487 LD C,A Store the location ID in C for later use.
CountObjectsInLocation_Loop 54488 CALL FetchNextObject Call FetchNextObject.
54491 JR Z,CountObjectsInLocation_End Jump to CountObjectsInLocation_End if we've reached the end of the object table (255).
54493 LD A,C Restore the location ID from C into A.
54494 CALL CheckObjectMatchCriteria Call CheckObjectMatchCriteria to check if this object matches the location and visibility criteria.
Skip this object if it doesn't match the criteria (carry flag not set).
54497 JR NC,CountObjectsInLocation_Loop Jump back to CountObjectsInLocation_Loop to continue checking objects if this one doesn't match.
This object matches the criteria, so count it.
54499 INC B Increment the object counter in B by one.
54500 JR CountObjectsInLocation_Loop Jump back to CountObjectsInLocation_Loop to check the next object.
CountObjectsInLocation_End 54502 LD A,B Transfer the object count from B to A.
54503 AND A Set flags based on the count (zero flag set if no objects found).
54504 POP BC Restore BC, HL, IY and IX from the stack.
54505 POP HL
54506 POP IY
54508 POP IX
54510 RET Return.
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