summaryrefslogtreecommitdiffstatshomepage
path: root/3rdparty/ymfm/src/ymfm_misc.cpp
blob: fd0575f55fb0267cd49bd972eb15fba37251da50 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
// BSD 3-Clause License
//
// Copyright (c) 2021, Aaron Giles
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "ymfm_misc.h"

namespace ymfm
{

//*********************************************************
//  YM2149
//*********************************************************

//-------------------------------------------------
//  ym2149 - constructor
//-------------------------------------------------

ym2149::ym2149(ymfm_interface &intf) :
	m_address(0),
	m_ssg(intf)
{
}


//-------------------------------------------------
//  reset - reset the system
//-------------------------------------------------

void ym2149::reset()
{
	// reset the engines
	m_ssg.reset();
}


//-------------------------------------------------
//  save_restore - save or restore the data
//-------------------------------------------------

void ym2149::save_restore(ymfm_saved_state &state)
{
	state.save_restore(m_address);
	m_ssg.save_restore(state);
}


//-------------------------------------------------
//  read_data - read the data register
//-------------------------------------------------

uint8_t ym2149::read_data()
{
	return m_ssg.read(m_address & 0x0f);
}


//-------------------------------------------------
//  read - handle a read from the device
//-------------------------------------------------

uint8_t ym2149::read(uint32_t offset)
{
	uint8_t result = 0xff;
	switch (offset & 3)	// BC2,BC1
	{
		case 0: // inactive
			break;

		case 1: // address
			break;

		case 2: // inactive
			break;

		case 3: // read
			result = read_data();
			break;
	}
	return result;
}


//-------------------------------------------------
//  write_address - handle a write to the address
//  register
//-------------------------------------------------

void ym2149::write_address(uint8_t data)
{
	// just set the address
	m_address = data;
}


//-------------------------------------------------
//  write - handle a write to the register
//  interface
//-------------------------------------------------

void ym2149::write_data(uint8_t data)
{
	m_ssg.write(m_address & 0x0f, data);
}


//-------------------------------------------------
//  write - handle a write to the register
//  interface
//-------------------------------------------------

void ym2149::write(uint32_t offset, uint8_t data)
{
	switch (offset & 3)	// BC2,BC1
	{
		case 0: // address
			write_address(data);
			break;

		case 1: // inactive
			break;

		case 2: // write
			write_data(data);
			break;

		case 3: // address
			write_address(data);
			break;
	}
}


//-------------------------------------------------
//  generate - generate samples of SSG sound
//-------------------------------------------------

void ym2149::generate(output_data *output, uint32_t numsamples)
{
	for (uint32_t samp = 0; samp < numsamples; samp++, output++)
	{
		// clock the SSG
		m_ssg.clock();

		// YM2149 keeps the three SSG outputs independent
		m_ssg.output(*output);
	}
}

}