/*
	Skelton for retropc emulator

	Origin : Neko Project 2
	Author : Takeda.Toshiya
	Date   : 2015.09.29-

	[ TMS3631 ]
*/

#include "tms3631.h"

// from tms3631c.c

static const uint16_t np2_freq_table[] = {
	0,	0x0c26, 0x0cdf, 0x0da3, 0x0e73, 0x0f4f, 0x1038,
		0x112f, 0x1234, 0x1349, 0x146f, 0x15a6, 0x16f0, 0,0,0,
	0,	0x184d, 0x19bf, 0x1b47, 0x1ce6, 0x1e9e, 0x2070,
		0x225d, 0x2469, 0x2693, 0x28de, 0x2b4c, 0x2ddf, 0,0,0,
	0,	0x3099, 0x337d, 0x368d, 0x39cb, 0x3d3b, 0x40df,
		0x44bb, 0x48d1, 0x4d26, 0x51bc, 0x5698, 0x5bbe, 0,0,0,
	0,	0x6133, 0x66fb, 0x6d1a, 0x7397, 0x7a77, 0x81bf,
		0x8976, 0x91a2, 0x9a4b, 0xa378, 0xad30, 0xb77d, 0xc266, 0,0
};

void TMS3631::reset()
{
	datareg = maskreg = 0;
	memset(ch, 0, sizeof(ch));
	channel = 0;
	set_key = false;
}

void TMS3631::write_signal(int id, uint32_t data, uint32_t mask)
{
	if(id == SIG_TMS3631_ENVELOP1) {
		touch_sound();
		envelop1 = (envelop1 & ~mask) | (data & mask);
	} else if(id == SIG_TMS3631_ENVELOP2) {
		touch_sound();
		envelop2 = (envelop2 & ~mask) | (data & mask);
	} else if(id == SIG_TMS3631_DATAREG) {
		// from board14.c
		touch_sound();
		data = (datareg & ~mask) | (data & mask);
		if(data & 0x80) {
			if(!(datareg & 0x80)) {
				set_key = true;
				channel = 0;
			} else if(set_key) {
				ch[channel].freq = freq_table[data & 0x3f];
				set_key = false;
			} else if(!(data & 0x40) && (datareg & 0x40)) {
				set_key = true;
				channel = (channel + 1) & 7;
			}
		}
		datareg = data;
	} else if(id == SIG_TMS3631_MASKREG) {
		touch_sound();
		maskreg = (maskreg & ~mask) | (data & mask);
	}
}

void TMS3631::mix(int32_t* buffer, int cnt)
{
	// from tms3631g.c
	for(int i = 0; i < cnt; i++) {
		int data = 0;
		int j = 0;
		if((maskreg & (1 << j)) && ch[j].freq != 0) {
			for(int k = 0; k < 4; k++) {
				ch[j].count += ch[j].freq;
				data += (ch[j].count & 0x10000) ? 1 : -1;
			}
		}
		int vol_l = data * vol;
		int vol_r = data * vol;
		j = 1;
		if((maskreg & (1 << j)) && ch[j].freq != 0) {
			for(int k = 0; k < 4; k++) {
				ch[j].count += ch[j].freq;
				vol_l += feet[(ch[j].count >> 16) & 15];
				vol_r += feet[(ch[j].count >> 16) & 15];
			}
		}
                for(int j = 2; j < 5; j++) {
                        if((maskreg & (1 << j)) && ch[j].freq != 0) {
                                for(int k = 0; k < 4; k++) {
                                        ch[j].count += ch[j].freq;
                                        vol_l += feet[(ch[j].count >> 16) & 15];
                                }
                        }
                }
                for(int j = 5; j < 8; j++) {
                        if((maskreg & (1 << j)) && ch[j].freq != 0) {
                                for(int k = 0; k < 4; k++) {
                                        ch[j].count += ch[j].freq;
                                        vol_r += feet[(ch[j].count >> 16) & 15];
                                }
                        }
                }
		*buffer++ += apply_volume(vol_l, volume_l); // L
		*buffer++ += apply_volume(vol_r, volume_r); // R
	}
}

void TMS3631::set_volume(int ch, int decibel_l, int decibel_r)
{
	volume_l = decibel_to_volume(decibel_l);
	volume_r = decibel_to_volume(decibel_r);
}

void TMS3631::initialize_sound(int rate, int volume)
{
	// from tms3631c.c
	for(int i = 0; i < 64; i++) {
		freq_table[i] = (uint32_t)((double)np2_freq_table[i] * 11025.0 / (double)rate / 2.0 + 0.5);
	}
	for(int i = 0; i < 16; i++) {
		int data = 0;
		for(int j = 0; j < 4; j++) {
			data += (volume / 8) * ((i & (1 << j)) ? 1 : -1);
		}
		feet[i] = data;
	}
	vol = volume / 8;
}

#define STATE_VERSION	2

bool TMS3631::process_state(FILEIO* state_fio, bool loading)
{
	if(!state_fio->StateCheckUint32(STATE_VERSION)) {
		return false;
	}
	if(!state_fio->StateCheckInt32(this_device_id)) {
		return false;
	}
	state_fio->StateValue(envelop1);
	state_fio->StateValue(envelop2);
	state_fio->StateValue(datareg);
	state_fio->StateValue(maskreg);
	for(int i = 0; i < array_length(ch); i++) {
		state_fio->StateValue(ch[i].freq);
		state_fio->StateValue(ch[i].count);
	}
	state_fio->StateValue(channel);
	state_fio->StateValue(set_key);
	return true;
}