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|
;
; Written by Groepaz/Hitmen <groepaz@gmx.net>
; Cleanup by Ullrich von Bassewitz <uz@cc65.org>
;
.export ppubuf_waitempty
.export ppubuf_wait
.export ppubuf_put
.export ppubuf_flush
.include "nes.inc"
.code
; ------------------------------------------------------------------------
; ppubuf_waitempty
; Wait until buffer is empty
.proc ppubuf_waitempty
@wait: lda ringcount
bne @wait
rts
.endproc
; ------------------------------------------------------------------------
; ppubuf_wait
; Wait until buffer is full
.proc ppubuf_wait
lda #$ff ; (($0100/3)*1)
@wait: cmp ringcount
beq @wait
rts
.endproc
; ------------------------------------------------------------------------
; Put a PPU-Memory write to buffer
; called from main program (not necessary when in vblank irq)
.proc ppubuf_put
sta ppuval
sty ppuhi
stx ppulo
jsr ppubuf_wait ; wait if buffer is full
ldy ringwrite
lda ppuhi
sta ringbuff,y
lda ppulo
sta ringbuff+$0100,y
lda ppuval
sta ringbuff+$0200,y
iny
sty ringwrite
inc ringcount
rts
.endproc
; ------------------------------------------------------------------------
; Flush PPU-Memory write buffer
; called from vblank interupt
.proc ppubuf_flush
ldy ringcount
bne @doloop
rts
@doloop:
ldx ringread
lda #$0e
sta temp
@loop:
.repeat 5
lda ringbuff,x
sta $2006
lda ringbuff+$0100,x
sta $2006
lda ringbuff+$0200,x
sta $2007
inx
dey
beq @end
.endrepeat
dec temp
bne @loop
@end: stx ringread
sty ringcount
rts
.endproc
; ------------------------------------------------------------------------
; Data
.bss
temp: .res 1
|
