98 lines
1.5 KiB
ArmAsm
98 lines
1.5 KiB
ArmAsm
; FIXME: should be able to drop pages back where we picked them up
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;==============================
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; Take Blue Page
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;==============================
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; A should be page to take (i.e. MECHE_PAGE or similar)
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take_blue_page:
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pha
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jsr drop_current_page
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pla
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pha
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eor BLUE_PAGES_TAKEN ; toggle the taken flag
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sta BLUE_PAGES_TAKEN
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pla
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ora #HOLDING_BLUE_PAGE ; put it in hand
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sta HOLDING_PAGE
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rts
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;==============================
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; Take Red Page
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;==============================
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; A should be page to take (i.e. MECHE_PAGE or similar)
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take_red_page:
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pha
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jsr drop_current_page
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pla
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pha
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eor RED_PAGES_TAKEN
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sta RED_PAGES_TAKEN
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pla
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ora #HOLDING_RED_PAGE
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sta HOLDING_PAGE
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rts
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;==============================
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; Take White Page
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;==============================
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take_white_page:
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pha
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jsr drop_current_page
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pla
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pha
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lda #1
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sta WHITE_PAGE_TAKEN
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pla
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ora #HOLDING_WHITE_PAGE
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sta HOLDING_PAGE
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rts
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;==============================
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; Drop current page
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;==============================
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; clicked on a page while holding another
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drop_current_page:
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lda HOLDING_PAGE
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and #$c0
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cmp #HOLDING_RED_PAGE
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beq drop_red_page
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cmp #HOLDING_BLUE_PAGE
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beq drop_blue_page
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cmp #HOLDING_WHITE_PAGE
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beq drop_white_page
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; there was no page?
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rts
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drop_white_page:
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lda #0
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sta WHITE_PAGE_TAKEN
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rts
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drop_red_page:
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lda HOLDING_PAGE
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and #$3f
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eor RED_PAGES_TAKEN
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sta RED_PAGES_TAKEN
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rts
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drop_blue_page:
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lda HOLDING_PAGE
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and #$3f
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eor BLUE_PAGES_TAKEN
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sta BLUE_PAGES_TAKEN
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rts
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