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60 lines
918 B
60 lines
918 B
INCLUDE "hardware.inc"
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Section "Input Data", WRAM0
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lastKeys:: db
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keys:: db
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Section "Input Code", ROM0
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; Initialize input
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; NOTE: Inline if needed
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Keys_Init::
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ld hl, lastKeys
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xor a
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ld [hl+], a
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ld [hl], a
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; Update the input state
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Keys_Update::
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ld a, P1F_GET_BTN
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ld [rP1], a
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; wait a few cycles
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ld a, [rP1]
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ld a, [rP1]
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; extract btn bits into top of B
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cpl
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and $f
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swap a
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ld b, a
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ld a, P1F_GET_DPAD
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ld [rP1], a
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; wait more cycles
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ld a, [rP1]
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ld a, [rP1]
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ld a, [rP1]
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ld a, [rP1]
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ld a, [rP1]
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ld a, [rP1]
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; extract dpad bits into bottom of B
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cpl
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and $f
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or b
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ld b, a
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; swap to use flag macros from hardware.inc
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; TODO: optimize this code to avoid swap (very small win)
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swap b
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; lastKeys <- keys ; keys <- B
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ld hl, keys
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ld a, [hl]
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ld [hl], b
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dec hl
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ld [hl], a
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ret
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