58 lines
877 B
NASM
58 lines
877 B
NASM
; ---------------------------------------------------------
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Menu_CheckHScroll:
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{
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LDA.b $F4
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BIT.b #$10 : BNE .leave_menu
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LDA.b $F6
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BIT.b #$20 : BNE .left
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BIT.b #$10 : BNE .right
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BIT.b #$80 : BNE .leave_menu
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RTS
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.left
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REP #$20
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LDA.w #$FFF8
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BRA .merge
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.right
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REP #$20
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LDA.w #$0008
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.merge
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STA.w MenuScrollHDirection
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SEP #$30
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INC.w $0200
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LDA.b #$06 : STA.w $012F
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RTS
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.leave_menu
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LDA.b #$0B : STA.w $0200
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RTS
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}
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; ---------------------------------------------------------
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Menu_ScrollHorizontal:
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{
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REP #$21 ; set A to 16 bit, clear carry flag
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LDA.w $E4 ; BG3 Horizontal Scroll Value
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ADC.w MenuScrollHDirection ; Direction set by Menu_CheckHScroll
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AND.w #$01FF
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STA.b $E4
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AND.w #$00FF
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BNE .loop
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SEC
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RTS
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.loop
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CLC
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RTS
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}
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