Routines
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43136: 1UP/ 2UP Swapper
Swaps the active and inactive player data. Exchanges the four player-state bytes at ActivePlayer_Level and InactivePlayer_Level, 1024 bytes of terrain between TerrainData_Active and TerrainData_Inactive, and 288 bytes of actor slots between Rover_Slot and Actor_List_End.
This routine "swaps" the data between DE and HL.
These are all the player states.
ChangePlayer 43136 LD HL,24224 HL=ActivePlayer_Level.
43139 LD DE,24228 DE=InactivePlayer_Level.
43142 LD B,4 Set a byte counter in B for 4 loops.
Exchange the four player-state bytes at ActivePlayer_Level with the inactive copy at InactivePlayer_Level.
ChangePlayer_States 43144 LD A,(DE) A=*DE.
43145 LD C,(HL) C=*HL.
43146 LD (HL),A Swap the bytes at *HL and *DE.
43147 LD A,C
43148 LD (DE),A
43149 INC HL Increment HL by one.
43150 INC DE Increment DE by one.
43151 DJNZ ChangePlayer_States Decrease the counter by one and jump back to ChangePlayer_States until it is zero.
This is the current terrain buffer data.
43153 LD HL,28672 HL=TerrainData_Active.
43156 LD DE,29696 DE=TerrainData_Inactive.
43159 LD BC,1024 Set the byte count in BC to 1024.
43162 CALL ChangePlayer_Loop Call ChangePlayer_Loop.
And this is the active sprites.
43165 LD HL,24720 HL=Rover_Slot.
43168 LD DE,25152 DE=Actor_List_End.
43171 LD BC,288 Set the byte count in BC to 288.
Exchange the bytes at HL and DE for BC counts.
ChangePlayer_Loop 43174 PUSH BC Stash BC on the stack.
43175 LD A,(DE) A=*DE.
43176 LD C,(HL) C=*HL.
43177 LD (HL),A Swap the bytes at *HL and *DE.
43178 LD A,C
43179 LD (DE),A
43180 INC HL Increment HL by one.
43181 INC DE Increment DE by one.
43182 POP BC Restore BC from the stack.
43183 DEC BC Decrease BC by one.
43184 LD A,B Jump back to ChangePlayer_Loop until BC is zero.
43185 OR C
43186 JR NZ,ChangePlayer_Loop
43188 RET Return.
View the equivalent code in;
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