Routines
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D4CC: Count Objects In Location
Used by the routines at DescribeCurrentRoom, PrintObjectList, PrintFormattedObjectList and MeasureGapBetweenTwoPointers_Next.
Counts how many objects are inside the current room.
Input
A Location ID (or FF for current character location)
Output
A Count of visible objects found in the specified location
CountObjectsInLocation D4CC PUSH IX Save the character record, the schedule entry, the pointer and the count.
D4CE PUSH IY
D4D0 PUSH HL
D4D1 PUSH BC
D4D2 CALL AdjustObjectTableForSum Call AdjustObjectTableForSum to set up the object table pointer.
D4D5 LD B,$00 Initialise the object counter in B to zero.
D4D7 LD C,A Store the location ID in C for later use.
CountObjectsInLocation_Loop D4D8 CALL FetchNextObject Go to CountObjectsInLocation_End if the next object id is FF.
D4DB JR Z,CountObjectsInLocation_End
D4DD LD A,C Take the count.
D4DE CALL CheckObjectMatchCriteria Call CheckObjectMatchCriteria to check if this object matches the location and visibility criteria.
Skip this object if it does not match the location and visibility criteria.
D4E1 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.
D4E3 INC B Increment the object counter in B by one.
D4E4 JR CountObjectsInLocation_Loop Jump back to CountObjectsInLocation_Loop to check the next object.
Read the count.
CountObjectsInLocation_End D4E6 LD A,B Transfer the object count from B to A.
D4E7 AND A Set the zero flag when the count is zero.
D4E8 POP BC Restore the saved count, the saved pointer, the saved schedule entry and the saved character record from the stack.
D4E9 POP HL
D4EA POP IY
D4EC POP IX
D4EE RET Return.
View the equivalent code in;
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