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Fix DMA fill so that it does not cause observable changes to the FIFO. Get DMA copy mostly correct from an observable ffect perspective. DMA copy probably does not reflect internal implementation still given that evidence seems to suggest no FIFO usage at all.
author Mike Pavone <pavone@retrodev.com>
date Tue, 17 Sep 2013 00:11:45 -0700
parents 140af5509ce7
children 3e1573fa22cf
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/*
 Copyright 2013 Michael Pavone
 This file is part of BlastEm. 
 BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
*/
#ifndef PSG_CONTEXT_H_
#define PSG_CONTEXT_H_

#include <stdint.h>

typedef struct {
	int16_t  *audio_buffer;
	int16_t  *back_buffer;
	double   buffer_fraction;
	double   buffer_inc;
	uint32_t buffer_pos;
	uint32_t clock_inc;
	uint32_t cycles;
	uint32_t samples_frame;
	uint16_t lsfr;
	uint16_t counter_load[4];
	uint16_t counters[4];
	uint8_t  volume[4];
	uint8_t  output_state[4];
	uint8_t  noise_out;
	uint8_t  noise_use_tone;
	uint8_t  noise_type;
	uint8_t  latch;
} psg_context;


void psg_init(psg_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t samples_frame);
void psg_write(psg_context * context, uint8_t value);
void psg_run(psg_context * context, uint32_t cycles);

#endif //PSG_CONTEXT_H_