Routines
Prev: BCE3 Up: Map Next: BD32
BD13: Reset Map
Used by the routine at DrawGameScreen.
Puts every cell of the map back to its initial type, by copying the upper four bits of each cell into the lower four bits.
ResetMap BD13 LD HL,$D355 Point HL at the end of the map.
BD16 LD BC,$C515 Point BC at Map.
BD19 AND A Find the size of the map...
BD1A SBC HL,BC
BD1C LD B,H ...and keep it in BC.
BD1D LD C,L
BD1E LD HL,$C515 Point HL at Map.
ResetMap_Cell BD21 LD A,(HL) Fetch a cell.
BD22 AND $F0 Keep the initial type.
BD24 LD D,A
BD25 RRA Move it into the lower four bits...
BD26 RRA
BD27 RRA
BD28 RRA
BD29 OR D ...and combine it with the original.
BD2A LD (HL),A Store the cell.
BD2B INC HL Move on to the next cell.
BD2C DEC BC Count down the size.
BD2D LD A,C Loop back until every cell has been reset.
BD2E OR B
BD2F JR NZ,ResetMap_Cell
BD31 RET Return.
Prev: BCE3 Up: Map Next: BD32