romram.src

;  romram - copy OS ROM to RAM
;
;  Copyright 2009 Matthias Reichl
;
;  This program is free software; you can redistribute it and/or modify
;  it under the terms of the GNU General Public License as published by
;  the Free Software Foundation; either version 2 of the License, or
;  (at your option) any later version.
;
;  This program is distributed in the hope that it will be useful,
;  but WITHOUT ANY WARRANTY; without even the implied warranty of
;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;  GNU General Public License for more details.
;
;  You should have received a copy of the GNU General Public License
;  along with this program; if not, write to the Free Software
;  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
;


; NOTE: you need to define a ZP location TMPVEC to use this code


ROMRAM	SEI
	LDY #0
	STY $D40E
	STY $D400
	STY TMPVEC
	LDA #$C0
	STA TMPVEC+1
?ROMMV	LDA (TMPVEC),Y
	DEC $D301
	STA (TMPVEC),Y
	INC $D301
	INY
	BNE ?ROMMV
	INC TMPVEC+1
	LDA TMPVEC+1
	BEQ ?ROMOK
	CMP #$D0
	BNE ?ROMMV
	LDA #$D8
	STA TMPVEC+1
	BNE ?ROMMV
?ROMOK	DEC $D301
	LDA #$40
	STA $D40E
	CLI
	RTS