BLARGGS_CODE.txt

;to determine if the system is ntsc or pal


	lda #%10000000
	sta PPU_CTRL		;enable NMI


waitSync3:				;wait for V-BLANK
	lda <FRAME_CNT1
@1:
	cmp <FRAME_CNT1
	beq @1

detectNTSC:
	ldx #52				;blargg's code
	ldy #24				;a timed loop
@1:
	dex
	bne @1
	dey
	bne @1

	lda PPU_STATUS
	and #$80
	sta <NTSC_MODE
	
	
;if PAL NES, the long NMI means that it won't have run into
;then next frame's NMI yet and PPU_STATUS bit 7 will be zero
;but NTSC will have run into the next frame's NMI

;the nmi code should do this...

	inc <FRAME_CNT1
	
	
;this NTSC_MODE variable is loaded to A register before
;calling the FamiToneInit, to set PAL vs NTSC mode