;MEGAMI TENSEI DTE ROUTINE
;For compilation with X816
;Note that the following three lines are NECESSARY because X816 is a compiler for
;the SUPER NES and NOT the normal NES. The following will basically "fool" x816 into
;compiling NES code instead of SNES code.
;NOTE: Manually insert a JSR $RoutineAddress at $AF24. Do not forget to add $10 to this
;address to compensate for the iNES header!

.org $8000
.mem 8
.index 8

DTE_Routine:
  LDY $0658        ;This was the first command I overwrote with the jump to the routine.
  LDA ($BE),Y      ;This is the second.
  CMP #$30         ;DTE Range compare 1
  BCC End          ;If A is < #$30, skip DTE (Branch if carry clear) 
  CLC              ;Clear the carry flag - we get here because
  CMP #$80         ;DTE Range Compare 2
  BCS End          ;If A is >=#$80, skip DTE (Branch if carry set)
                   ;If we get past the upper and lower bound range compares, we have DTE!
RunCheck:
  STX $07FE        ;Store X temporarily to THE DEPTHS OF UNUSED RAM
  SEC
  SBC #$30
  CLC
  LDX $07FF        ;Load X with a test byte from THE DEPTHS OF UNUSED RAM
  CPX #$9D         ;Compare it with test=true (#$9D in this case)
  BEQ SecondRun    ;If test=true, we're printing the second character
  BNE FirstRun     ;If test=false, we're printing the FIRST character.
  

FirstRun:          ;For outputting the first character...
  LDX #$9D         ;Load X with Test=true
  DEC $0658        ;Decrement load index (which gets transferred into Y)
  ASL A            ;Double A to get DTE Pair Number
  JMP Base_Routine ;Jump to the shared bits of the routine (4C2780)

SecondRun:
  ASL A            ;Double A for DTE Pair Number
  CLC              ;Clear the carry cuz we're gonna add
  ADC #$01         ;Increment the accumulator
                   ;A is now the index location of the second byte in the DTE Pair.
  LDX #$00         ;Load X with Test=FALSE

Base_Routine:
  STX $07FF        ;Store test byte to THE DEPTHS OF UNUSED RAM
  TAX              ;Transer A to X for the DTE table lookup
  LDA $DTETable,X  ;Load A with where ever your DTE table happens to be,X
  LDX $07FE        ;Restore X from before routine

End:
  JMP $AF29        ;Jump back to the routine
  

Create_DTE_Table:
.DSW 80            ;Create an 80 ($50) byte empty DTE table to be later filled in
                   ;This gets put -immediately- after the routine.