Routines
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51000: Get Map Cell
Used by the routines at CreateOutlaw, PlaceNearSheriff, DrawTown, DrawCell and DrawCellWithWalls.
Fetches the code of a cell from TownMap, which is sixteen rows of sixteen. L is the column and H is the row. It sets CellColumn and CellRow. When bit 0 of ViewRotation is set, the map is read from the end.
Input
HL The cell: the column in L and the row in H
Output
A The code for the cell
F The zero flag is set if the cell is empty
Work out the number of the cell.
GetMapCell 51000 LD (41556),HL Set CellColumn and CellRow.
51003 LD A,L Put the column in A and the row in HL.
51004 LD L,H
51005 LD H,0
51007 ADD HL,HL Multiply the row by 16.
51008 ADD HL,HL
51009 ADD HL,HL
51010 ADD HL,HL
51011 OR L Add the column.
51012 LD L,A
Point at the map.
51013 LD BC,24497 Point BC at TownMap.
51016 LD A,(41576) Fetch ViewRotation.
51019 AND %00000001 Keep the lowest bit.
51021 JR Z,GetMapCell_Fetch Jump to GetMapCell_Fetch if the view is not rotated.
Read from the end.
51023 LD A,L Complement HL.
51024 CPL
51025 LD L,A
51026 LD A,H
51027 CPL
51028 LD H,A
51029 LD BC,24753 Point BC one past TownMap.
Fetch the code.
GetMapCell_Fetch 51032 ADD HL,BC Add the address of the map.
51033 LD A,(HL) Fetch the code and return.
51034 AND A
51035 RET
View the equivalent code in;
Prev: 50908 Up: Map Next: 51036