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35 lines
1014 B
ArmAsm
35 lines
1014 B
ArmAsm
;
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; 2020-05-02, Greg King
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;
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; unsigned char __fastcall__ vera_sprites_enable (unsigned char mode);
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; /* Enable the sprite engine when mode is non-zero (true);
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; ** disable sprites when mode is zero. Return the previous mode.
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; */
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;
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.export _vera_sprites_enable
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.include "cx16.inc"
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.proc _vera_sprites_enable
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stz VERA::CTRL ; Use display register bank 0
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tax ; Is mode true?
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beq :+
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lda #VERA::DISP::ENABLE::SPRITES ; Yes
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: ldy VERA::DISP::VIDEO
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eor VERA::DISP::VIDEO
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and #VERA::DISP::ENABLE::SPRITES
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eor VERA::DISP::VIDEO ; Replace old flag with new flag
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sta VERA::DISP::VIDEO
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tya
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and #VERA::DISP::ENABLE::SPRITES ; Get old value
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asl a
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asl a
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rol a ; Make it boolean
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ldx #>$0000
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rts
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.endproc
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