Routines
Prev: A84C Up: Map Next: A8B5
A880: 1UP/ 2UP Swapper
Used by the routines at NewGame and A8B5.
This routine "swaps" the data between DE and HL.
These are all the player states.
ChangePlayer A880 LD HL,$5EA0 HL=ActivePlayer_Level.
A883 LD DE,$5EA4 DE=InactivePlayer_Level.
A886 LD B,$04 B=04 (counter).
This looks complicated but it's just grabbing the data from DE, grabbing the data from HL, and writing the others data to each one.
ChangePlayer_States A888 LD A,(DE) A=fetch byte from DE.
A889 LD C,(HL) C=fetch byte from HL.
A88A LD (HL),A Write the byte from DE to HL, and the byte from HL to DE.
A88B LD A,C
A88C LD (DE),A
A88D INC HL Increment HL by one.
A88E INC DE Increment DE by one.
A88F DJNZ ChangePlayer_States Decrease counter by one and loop back to ChangePlayer_States until counter is zero.
This is the current terrain buffer data.
A891 LD HL,$7000 HL=TerrainData_Active.
A894 LD DE,$7400 DE=TerrainData_Inactive.
A897 LD BC,$0400 BC=0400 (counter).
A89A CALL ChangePlayer_Loop Call ChangePlayer_Loop.
And this is the active sprites.
A89D LD HL,$6090 HL=6090.
A8A0 LD DE,$6240 DE=6240.
A8A3 LD BC,$0120 BC=0120 (counter).
This is identical to the copier routine above, except it uses BC for the counter and not only B.
ChangePlayer_Loop A8A6 PUSH BC Stash BC on the stack.
A8A7 LD A,(DE) A=fetch byte from DE.
A8A8 LD C,(HL) C=fetch byte from HL.
A8A9 LD (HL),A Write the byte from DE to HL, and the byte from HL to DE.
A8AA LD A,C
A8AB LD (DE),A
A8AC INC HL Increment HL by one.
A8AD INC DE Increment DE by one.
A8AE POP BC Restore BC from the stack.
A8AF DEC BC Decrease BC by one.
A8B0 LD A,B Jump back to ChangePlayer_Loop until BC is zero.
A8B1 OR C
A8B2 JR NZ,ChangePlayer_Loop
A8B4 RET Return.
View the equivalent code in;
Prev: A84C Up: Map Next: A8B5