23 строки
508 B
NASM
23 строки
508 B
NASM
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;--------------------
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; Video Subroutines
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;--------------------
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SECTION "VBlank Int", ROM0[$40]
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ld a, 1
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ld [hVBlankFlag], a
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reti
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SECTION "Vid Subs", ROM0
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Wait_VBlank::
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ld hl, hVBlankFlag ; hl=pointer to vblank_flag
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.wait: ; wait...
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halt ; suspend CPU - wait for ANY interrupt
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nop
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xor a
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cp a,[hl] ; vblank flag still zero?
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jr z, .wait ; wait more if zero
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ld [hl],a ; set vblank_flag back to zero
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ret
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