55 lines
1.6 KiB
NASM
55 lines
1.6 KiB
NASM
; =========================================================
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; Book of Secrets (Reveal Secrets with Book of Mudora)
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; Makes BG2 Disappear when holding L in a building
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; Based on the Parallel Worlds feature
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;
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; Layer Flags: xxxsabcd (i count BG from 1 to 4 - MathOnNapkins RAM-Map counts from 0 to 3)
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; s - Sprite layer enabled
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; a - BG4 enabled
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; b - BG3 enabled
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; c - BG2 enabled
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; d - (BG1 disabled) --> only works properly if the room uses the feature "BG2 on Top"
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;
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; Originally by XaserLE, updated by scawful
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; =========================================================
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; long subroutine that is executed every frame
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org $068365
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JSL LinkItem_SecretsBook ; overwrite it (originally JSL $099F91)
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; =========================================================
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pullpc
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LinkItem_SecretsBook:
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{
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; Check if we are in a building
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LDA $1B : AND #$01 : BEQ .end
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; ----------
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; Check if we have the book of secrets
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LDA $7EF34D : CMP #$01 : BNE $0F ; if not, go to enable BG2
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; load unfiltered joypad 1 register (AXLR|????)
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; delete all bits except those for L
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LDA $F2 : AND #$20
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; L button pressed? (if yes, zero flag is set)
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SEC : SBC #$20 : BNE $06 ; if not, go to enable BG2
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; load layer flags and disable BG2 (0xFD = 11111101)
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LDA $1C : AND #$FD : BRA $04 ; go to store layer flags
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; enable BG2 (0x02 = 00000010)
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LDA $1C : ORA #$02 : STA $1C
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; ----------
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.end
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JSL $099F91 ; at least execute original code
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RTL
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}
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print "End of Items/book_of_secrets.asm ", pc
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pushpc
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