NBA Jam Tournament Edition:ROM map:Titlescreen code
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This is a sub-page for NBA Jam Tournament Edition:ROM map.
This code loops through a series of 16 bit values (8 of them) stored at 0B7C3A [$16:FC3A] and compares them to player input. Then sets a bit at $16FF if entered correctly.
Commented titlescreen input check routine
------------------------- here are the input values ------------------------- org $16FC3A dw #$4000 ;Y dw #$0800 ;up dw #$0400 ;down dw #$8000 ;B dw #$0200 ;left dw #$0080 ;A dw #$0100 ;right dw #$0400 ;down -------------------------------------- get total correct input amount counter -------------------------------------- $8A/8847 AE FD 16 LDX $16FD [$00:16FD] A:4000 X:0034 -------------------------------------------- use that as an index to get next input value -------------------------------------------- $8A/884A BF 3A FC 16 LDA $16FC3A,x[$16:FC3A] A:4000 X:0000 ----------------------------------------- compare next input value to current input ----------------------------------------- $8A/884E C5 88 CMP $88 [$00:0088] A:4000 X:0000 $8A/8850 D0 12 BNE $12 [$8864] A:4000 X:0000 $8A/8852 E8 INX A:4000 X:0000 $8A/8853 E8 INX A:4000 X:0001 $8A/8854 8E FD 16 STX $16FD [$00:16FD] A:4000 X:0002 --------------------------------------- compare to 16 decimal (8 correct inputs) --------------------------------------- $8A/8857 E0 10 00 CPX #$0010 A:4000 X:0002 $8A/885A D0 0E BNE $0E [$886A] A:4000 X:0002 -------------------------- code was entered correctly -------------------------- $8A/885C A9 01 00 LDA #$0001 A:0400 X:0010 $8A/885F 8D FF 16 STA $16FF [$00:16FF] A:0001 X:0010 $8A/8862 80 06 BRA $06 [$886A] A:0001 X:0010 -------------------------------------------------- wrong input, reset the total correct input counter -------------------------------------------------- $8A/8864 A9 00 00 LDA #$0000 A:FFFF X:0010 $8A/8867 8D FD 16 STA $16FD [$00:16FD] A:0000 X:0010 $8A/886A end