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base:turbo250_disassembled [2015-04-17 04:34] (current)
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 +====== Turbo 250 Mr.Z Disassembled ======
  
 +Written by FTC
 +
 +This was disassembled the other day using IDA Pro (an old but useable freeware dos version available at 6502.org) and then converted it into ACME format. The process involved "​decoding"​ some EOR'ed blocks of code, and therefore slight changes had to be made to the startup code. (To be able to convert all parts of the program into readable assembler source rather than EOR'ed data.)
 +
 +The source is hardly labelled at all, but I guess it could still be nice to have a look at for some people. I might update it sometime, but don't count on it.
 +
 +I just couldn'​t resist looking under the hood of this extremely classic piece of software. ;)
 +
 +<​code>​
 +;​============================================================================
 +
 + * =  $0801
 +
 +basic_startup:​
 + !byte ​ $10 ;  ​
 + !byte 8 ;  ​
 + !byte $A ;  ​
 + !byte 0 ;  ​
 + !byte ​ $9E ;
 + !byte ​ $32 ; 2
 + !byte ​ $30 ; 0
 + !byte ​ $36 ; 6
 + !byte ​ $36 ; 6
 + !byte ​ $20 ;  ​
 +eorval1:​ !byte ​ $4D ; M
 +eorval2:​ !byte ​ $52 ; R
 +eorval3:​ !byte ​ $2E ; .
 +eorval4:​ !byte ​ $5A ; Z
 + !byte 0 ;  ​
 + !byte 0 ;  ​
 + !byte 0 ;  ​
 +;​============================================================================
 +;​ ldx lamerprotection
 +; stx $fb
 + ldx #0
 +
 +printmsg:​ ;​ code xref: 0824j
 + lda string,​x ;lda string-$4d,​x ;​$4d = EOR instructino at lamerprotection
 + beq lamerprotection ;​bypass message ​
 + jsr $e716
 +; eor $fb
 +; sta $fb
 + inx
 + bne printmsg
 +
 +lamerprotection:​ ;​ code xref: 081aj
 + ; data xref: 0812r
 + eor #​$ff ;​ a=ff x=fa y=90 fb=d5
 + tay
 + iny
 + ldx #$ff
 + txs
 + ldx #$55
 +
 +copy1: ; code xref: 083dj
 + lda code1,​y ;​ y=0
 +;​ eor $fb ;​ fb=d5
 +;​ eor $7b6,​x ;​ 080d=$4d
 + sta $2a7,​y
 + iny
 + cpy #$58
 + bne copy1
 + ldy #0
 +
 +copy2: ; code xref: 084fj
 + lda code2,​y
 +;​ eor $fb ;​ fb=d5
 +;​ eor $7b7,​x ;​ 080e=52
 + sta $334,​y
 + iny
 + cpy #$c7
 + bne copy2
 + ldy #0
 +
 +copy3: ; code xref: 0861j
 + lda code3,​y
 +;​ eor $fb ;​ fb=d5
 +;​ eor $7b8,​x ;​ 080f=2e
 + sta $10b,​y
 + iny
 + cpy #$97
 + bne copy3
 + ldy #0
 +
 +copy4: ; code xref: 0873j
 + lda code4,​y
 +;​ eor $fb ;​ fb=d5
 +;​ eor $7b9,​x ;​ 0810=5a
 + sta $ff3b,​y
 + iny
 + cpy #$c5
 + bne copy4
 + lda #$a7
 + ldx #2
 + sta $308 ;​ basic caracter dispatch
 + stx $309
 + jmp $a474 ;​ restart basic
 +;​============================================================================
 +string:​ !byte ​ $93 ; “
 + !byte ​ $8E ; Ž
 + !byte ​ $B0 ; °
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $AE ; ®
 + !byte $D ;  ​
 + !byte ​ $C2 ; Â
 + !byte ​ $20 ;  ​
 + !byte ​ $54 ; T
 + !byte ​ $55 ; U
 + !byte ​ $52 ; R
 + !byte ​ $42 ; B
 + !byte ​ $4F ; O
 + !byte ​ $20 ;  ​
 + !byte ​ $32 ; 2
 + !byte ​ $35 ; 5
 + !byte ​ $30 ; 0
 + !byte ​ $20 ;  ​
 + !byte ​ $42 ; B
 + !byte ​ $59 ; Y
 + !byte ​ $20 ;  ​
 + !byte ​ $4D ; M
 + !byte ​ $52 ; R
 + !byte ​ $2E ; .
 + !byte ​ $5A ; Z
 + !byte ​ $20 ;  ​
 + !byte ​ $C2 ; Â
 + !byte $D ;  ​
 + !byte ​ $C2 ; Â
 + !byte ​ $43 ; C
 + !byte ​ $41 ; A
 + !byte ​ $4E ; N
 + !byte ​ $20 ;  ​
 + !byte ​ $48 ; H
 + !byte ​ $41 ; A
 + !byte ​ $4E ; N
 + !byte ​ $44 ; D
 + !byte ​ $4C ; L
 + !byte ​ $45 ; E
 + !byte ​ $20 ;  ​
 + !byte ​ $50 ; P
 + !byte ​ $52 ; R
 + !byte ​ $4F ; O
 + !byte ​ $47 ; G
 + !byte ​ $52 ; R
 + !byte ​ $41 ; A
 + !byte ​ $4D ; M
 + !byte ​ $53 ; S
 + !byte ​ $C2 ; Â
 + !byte $D ;  ​
 + !byte ​ $C2 ; Â
 + !byte ​ $42 ; B
 + !byte ​ $45 ; E
 + !byte ​ $54 ; T
 + !byte ​ $57 ; W
 + !byte ​ $45 ; E
 + !byte ​ $45 ; E
 + !byte ​ $4E ; N
 + !byte ​ $20 ;  ​
 + !byte ​ $24 ; $
 + !byte ​ $30 ; 0
 + !byte ​ $38 ; 8
 + !byte ​ $30 ; 0
 + !byte ​ $31 ; 1
 + !byte ​ $2D ; -
 + !byte ​ $24 ; $
 + !byte ​ $46 ; F
 + !byte ​ $46 ; F
 + !byte ​ $33 ; 3
 + !byte ​ $42 ; B
 + !byte ​ $C2 ; Â
 + !byte $D ;  ​
 + !byte ​ $AB ; «
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $B3 ; ³
 + !byte $D ;  ​
 + !byte ​ $C2 ; Â
 + !byte ​ $5F ; _
 + !byte ​ $4C ; L
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $20 ;  ​
 + !byte ​ $4C ; L
 + !byte ​ $4F ; O
 + !byte ​ $41 ; A
 + !byte ​ $44 ; D
 + !byte ​ $20 ;  ​
 + !byte ​ $50 ; P
 + !byte ​ $52 ; R
 + !byte ​ $4F ; O
 + !byte ​ $47 ; G
 + !byte ​ $C2 ; Â
 + !byte $D ;  ​
 + !byte ​ $C2 ; Â
 + !byte ​ $5F ; _
 + !byte ​ $53 ; S
 + !byte ​ $20 ;  ​
 + !byte ​ $28 ; (
 + !byte ​ $4E ; N
 + !byte ​ $41 ; A
 + !byte ​ $4D ; M
 + !byte ​ $45 ; E
 + !byte ​ $29 ; )
 + !byte ​ $20 ;  ​
 + !byte ​ $53 ; S
 + !byte ​ $41 ; A
 + !byte ​ $56 ; V
 + !byte ​ $45 ; E
 + !byte ​ $20 ;  ​
 + !byte ​ $50 ; P
 + !byte ​ $52 ; R
 + !byte ​ $4F ; O
 + !byte ​ $47 ; G
 + !byte ​ $C2 ; Â
 + !byte $D ;  ​
 + !byte ​ $AD ; ­
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $C3 ; Ã
 + !byte ​ $BD ; ½
 + !byte 0 ;  ​
 +
 +;##################################################################################​
 +;##################################################################################​
 +;##################################################################################​
 +code1:
 +!pseudopc $2a7 {
 +;​============================================================================
 + JSR $73
 + BEQ loc_0_2B0
 + CMP #$5F
 + BEQ loc_0_2B3
 +
 +loc_0_2B0:​ ;​ CODE XREF: 02AAj
 + JMP $A7E7
 +;​============================================================================
 +
 +loc_0_2B3:​ ;​ CODE XREF: 02AEj
 + JSR $73
 + CMP #$4C
 + BEQ loc_0_2C1
 + CMP #$53
 + BEQ loc_0_2C4
 + JMP $AF08
 +;​============================================================================
 +
 +loc_0_2C1:​ ;​ CODE XREF: 02B8j
 + JMP loc_0_111
 +;​============================================================================
 +
 +loc_0_2C4:​ ;​ CODE XREF: 02BCj
 + JMP loc_0_120
 +;​============================================================================
 +
 +loc_0_2C7:​ ;​ CODE XREF: 011Aj
 + LDX #0
 + STX $A
 + STX $93
 + STX $90
 +
 +loc_0_2CF:​ ;​ CODE XREF: 02DAj
 + JSR loc_0_334
 + LDA $AB
 + CMP #1
 + BEQ loc_0_2DC
 + CMP #2
 + BNE loc_0_2CF
 +
 +loc_0_2DC:​ ;​ CODE XREF: 02D6j
 + DEC $B3
 + JSR $F750
 + INC $B3
 + JSR $A82C
 + JSR $F5D2
 + JSR loc_0_355
 + LDA $BD
 + EOR $D7
 + BEQ loc_0_2F6
 + LDA #$FF
 + STA $90
 +
 +loc_0_2F6:​ ;​ CODE XREF: 02F0j
 + JSR $F5A9
 + JSR $E195
 + JMP $A7AE
 +;​============================================================================
 +
 +}
 +
 +
 +;##################################################################################​
 +;##################################################################################​
 +;##################################################################################​
 +code2:
 +!pseudopc $334 {
 +;​============================================================================
 +
 +loc_0_334:​ ;​ CODE XREF: 0339j
 + JSR sub_0_388
 + CMP #0
 + BEQ loc_0_334
 + STA $AB
 +
 +loc_0_33D:​ ;​ CODE XREF: 0346j
 + JSR sub_0_3B6
 + STA $AC,Y
 + INY
 + CPY #5
 + BNE loc_0_33D
 +
 +loc_0_348:​ ;​ CODE XREF: 0351j
 + JSR sub_0_3B6
 + STA $23C,​Y
 + INY
 + CPY #$15
 + BNE loc_0_348
 + BEQ sub_0_37C
 +
 +loc_0_355:
 + JSR sub_0_388
 +
 +loc_0_358:​ ;​ CODE XREF: 0373j
 + JSR sub_0_3B6
 + LDA #4
 + STA 1
 + LDA $BD
 + STA ($AC),​Y
 + LDA #7
 + STA 1
 + LDA $BD
 + EOR $D7
 + STA $D7
 + JSR $FCDB
 + JSR $FCD1
 + BCC loc_0_358
 + JSR sub_0_3B6
 + JSR sub_0_3E0
 + INY
 +
 +;############################################################################​
 +
 +; S u b r o u t i n e
 +
 +sub_0_37C:​ ;​ CODE XREF: 017Cp 0353j
 + STY $C0
 + CLI
 + CLC
 + LDA #0
 + STA $2A0
 + JMP $FC93
 +; End of function sub_0_37C
 +
 +
 +;############################################################################​
 +
 +; S u b r o u t i n e
 +
 +sub_0_388:​ ;​ CODE XREF: 0334p 0355p
 + JSR loc_0_10B
 + JSR sub_0_3E0
 + STY $D7
 + LDA #7
 + STA $DD06
 + LDX #1
 +
 +loc_0_397:​ ;​ CODE XREF: sub_0_388+18j
 + ; sub_0_388+25j
 + JSR sub_0_3C9
 + ROL $BD
 + LDA $BD
 + CMP #2
 + BNE loc_0_397
 + LDY #9
 +
 +loc_0_3A4:​ ;​ CODE XREF: sub_0_388+21j
 + JSR sub_0_3B6
 + CMP #2
 + BEQ loc_0_3A4
 +
 +loc_0_3AB:​ ;​ CODE XREF: sub_0_388+2Bj
 + CPY $BD
 + BNE loc_0_397
 + JSR sub_0_3B6
 + DEY
 + BNE loc_0_3AB
 + RTS
 + ; End of function sub_0_388
 +
 +
 + ;############################################################################​
 +
 + ; S u b r o u t i n e
 +
 +sub_0_3B6:​ ;​ CODE XREF: 033Dp 0348p 0358p 0375p
 + ; ...
 + LDA #8
 + STA $A3
 +
 +loc_0_3BA:​ ;​ CODE XREF: sub_0_3B6+Ej
 + JSR sub_0_3C9
 + ROL $BD
 + NOP
 + NOP
 + NOP
 + DEC $A3
 + BNE loc_0_3BA
 + LDA $BD
 + RTS
 + ; End of function sub_0_3B6
 +
 +
 + ;############################################################################​
 +
 + ; S u b r o u t i n e
 +
 +sub_0_3C9:​ ;​ CODE XREF: sub_0_388+Fp sub_0_3B6+4p
 + LDA #$10
 +
 +loc_0_3CB:​ ;​ CODE XREF: sub_0_3C9+5j
 + BIT $DC0D
 + BEQ loc_0_3CB
 + LDA $DD0D
 + STX $DD07
 + PHA
 + LDA #$19
 + STA $DD0F
 + PLA
 + LSR
 + LSR
 + RTS
 + ; End of function sub_0_3C9
 +
 +
 + ;############################################################################​
 +
 + ; S u b r o u t i n e
 +
 +sub_0_3E0:​ ;​ CODE XREF: 0168p 0378p sub_0_388+3p
 + LDY #0
 + STY $C0
 + LDA $D011
 + AND #$EF
 + STA $D011
 +
 +loc_0_3EC:​ ;​ CODE XREF: sub_0_3E0+Dj sub_0_3E0+10j
 + DEX
 + BNE loc_0_3EC
 + DEY
 + BNE loc_0_3EC
 + SEI
 + RTS
 + ; End of function sub_0_3E0
 +
 + ;​============================================================================
 +
 +irq:
 + LDA #$37 ; '​7'​
 + STA 1
 + JMP $FE69
 + ;​============================================================================
 +}
 +
 +
 +
 +;##################################################################################​
 +;##################################################################################​
 +;##################################################################################​
 +code3:​ ;​!bin "​block3.PRG",,​2
 + !pseudopc $10b {
 + ;​============================================================================
 +
 +loc_0_10B:
 + JSR $F817
 + JMP $A82C
 + ;​============================================================================
 +
 +loc_0_111:
 + JSR $73
 + BEQ loc_0_11A
 + CMP #$3A
 + BNE loc_0_11D
 +
 +loc_0_11A:​ ;​ CODE XREF: 0114j
 + JMP loc_0_2C7
 + ;​============================================================================
 +
 +loc_0_11D:​ ;​ CODE XREF: 0118j
 + JMP $AF08
 + ;​============================================================================
 +
 +loc_0_120:
 + LDX $37
 + LDY $38
 + STX $FB
 + STY $FC
 + LDX $2D
 + LDY $2E
 + STX $FD
 + STY $FE
 + LDX #$F8
 + LDY #7
 + STX $37
 + STY $38
 + LDX #$E8
 + LDY #7
 + STX $2D
 + STY $2E
 + JSR $A660
 + LDX #$82
 + LDY #1
 + STX $302
 + STY $303
 + JSR $73
 + JSR $E1D4
 + LDX #5
 + STX $AB
 + DEX
 +
 +loc_0_158:​ ;​ CODE XREF: 015Dj
 + LDA $2A,X
 + STA $AB,X
 + DEX
 + BNE loc_0_158
 + JSR $F838
 + JSR $A82C
 + JSR $F68F
 + JSR sub_0_3E0
 + SEI
 + LDA #$7F
 + STA $DD0D
 + LDA #4
 + STA 1
 + JSR loc_0_FF3B
 + LDA #7
 + STA 1
 + JSR sub_0_37C
 + JMP $A474
 + ;​============================================================================
 + LDA #$83
 + STA $302
 + LDA #$A4
 + STA $303
 + LDA $FB
 + STA $37
 + LDA $FC
 + STA $38
 + LDA $FD
 + STA $2D
 + LDA $FE
 + STA $2E
 + JSR $A660
 + JMP ($302)
 + ;​============================================================================
 +}
 +
 +;##################################################################################​
 +;##################################################################################​
 +;##################################################################################​
 +code4:
 +!pseudopc $ff3b {
 + ;​============================================================================
 +
 +loc_0_FF3B:
 + LDA $FD
 + STA $AE
 + LDA $FE
 + STA $AF
 + JSR sub_0_FFAB
 + LDA $B9
 + LDA #2
 + NOP
 + DEX
 + JSR sub_0_FFCB
 + LDX #8
 +
 +loc_0_FF51:​ ;​ CODE XREF: FF5Dj
 + LDA $AC,Y
 + JSR sub_0_FFCB
 + LDX #6
 + INY
 + CPY #5
 + NOP
 + BNE loc_0_FF51
 + LDY #0
 + LDX #4
 +
 +loc_0_FF63:​ ;​ CODE XREF: FF74j
 + LDA ($BB),​Y
 + CPY $B7
 + BCC loc_0_FF6C
 + LDA #$20
 + DEX
 +
 +loc_0_FF6C:​ ;​ CODE XREF: FF67j
 + JSR sub_0_FFCB
 + LDX #5
 + INY
 + CPY #$BB
 + BNE loc_0_FF63
 + LDA #2
 + STA $AB
 + JSR sub_0_FFAB
 + TYA
 + JSR sub_0_FFCB
 + STY $D7
 + LDX #7
 + NOP
 +
 +loc_0_FF86:​ ;​ CODE XREF: FF9Dj
 + LDA ($AC),​Y
 + JSR sub_0_FFCB
 + LDX #3
 + INC $AC
 + BNE loc_0_FF95
 + INC $AD
 + DEX
 + DEX
 +
 +loc_0_FF95:​ ;​ CODE XREF: FF8Fj
 + LDA $AC
 + CMP $AE
 + LDA $AD
 + SBC $AF
 + BCC loc_0_FF86
 +
 +loc_0_FF9F:​ ;​ CODE XREF: FFA7j
 + LDA $D7
 + JSR sub_0_FFCB
 + LDX #7
 + DEY
 + BNE loc_0_FF9F
 + INY
 + RTS
 +
 + ;############################################################################​
 +
 + ; S u b r o u t i n e
 +
 +sub_0_FFAB:​ ;​ CODE XREF: FF43p FF7Ap
 + LDY #0
 +
 +loc_0_FFAD:​ ;​ CODE XREF: sub_0_FFAB+Cj
 + ; sub_0_FFAB+12j
 + LDA #2
 + JSR sub_0_FFCB
 + LDX #7
 + DEY
 + CPY #9
 + BNE loc_0_FFAD
 + LDX #5
 + DEC $AB
 + BNE loc_0_FFAD
 +
 +loc_0_FFBF:​ ;​ CODE XREF: sub_0_FFAB+1Bj
 + TYA
 + JSR sub_0_FFCB
 + LDX #7
 + DEY
 + BNE loc_0_FFBF
 + DEX
 + DEX
 + RTS
 + ; End of function sub_0_FFAB
 +
 +
 + ;############################################################################​
 +
 + ; S u b r o u t i n e
 +
 +sub_0_FFCB:​ ;​ CODE XREF: FF4Cp FF54p FF6Cp FF7Ep
 + ; ...
 + STA $BD
 + EOR $D7
 + STA $D7
 + LDA #8
 + STA $A3
 +
 +loc_0_FFD5:​ ;​ CODE XREF: sub_0_FFCB+1Fj
 + ASL $BD
 + LDA 1
 + AND #$F7
 + JSR sub_0_FFED
 + LDX #$11
 + NOP
 + ORA #8
 + JSR sub_0_FFED
 + LDX #$E
 + DEC $A3
 + BNE loc_0_FFD5
 + RTS
 + ; End of function sub_0_FFCB
 +
 +
 + ;############################################################################​
 +
 + ; S u b r o u t i n e
 +
 +sub_0_FFED:​ ;​ CODE XREF: sub_0_FFCB+10p
 + ; sub_0_FFCB+18p sub_0_FFED+1j
 + DEX
 + BNE sub_0_FFED
 + BCC loc_0_FFF7
 + LDX #$B
 +
 +loc_0_FFF4:​ ;​ CODE XREF: sub_0_FFED+8j
 + DEX
 + BNE loc_0_FFF4
 +
 +loc_0_FFF7:​ ;​ CODE XREF: sub_0_FFED+3j
 + STA 1
 + RTS
 + ; End of function sub_0_FFED
 +
 + ;​============================================================================
 + ;Interrupt handler pointers which ends up at $fffa - $ffff
 + !WORD irq
 + !WORD irq
 + !WORD irq
 +}
 +</​code>​
base/turbo250_disassembled.txt · Last modified: 2015-04-17 04:34 (external edit)