OXYGENHUB
◆ main openmsx / src / sound / MSXMusic.cc
4.0 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
1 
#include "MSXMusic.hh"
2
3 
#include "CacheLine.hh"
4 
#include "MSXException.hh"
5 
#include "serialize.hh"
6
7 
#include <bit>
8
9 
namespace openmsx {
10
11 
// class MSXMusicBase
12
13 
MSXMusicBase::MSXMusicBase(DeviceConfig& config)
14 
	: MSXDevice(config)
15 
	, rom(getName() + " ROM", "rom", config)
16 
	, ym2413(getName(), config)
17 
{
18 
	if (!std::has_single_bit(rom.size())) {
19 
		throw MSXException("MSX-Music ROM-size must be a non-zero power of two");
20 
	}
21 
	MSXMusicBase::reset(getCurrentTime());
22 
}
23
24 
void MSXMusicBase::reset(EmuTime time)
25 
{
26 
	ym2413.reset(time);
27 
}
28
29 
void MSXMusicBase::writeIO(uint16_t port, byte value, EmuTime time)
30 
{
31 
	writePort(port & 1, value, time);
32 
}
33
34 
void MSXMusicBase::writePort(bool port, byte value, EmuTime time)
35 
{
36 
	ym2413.writePort(port, value, time);
37 
}
38
39 
byte MSXMusicBase::peekMem(uint16_t address, EmuTime /*time*/) const
40 
{
41 
	return *MSXMusicBase::getReadCacheLine(address);
42 
}
43
44 
byte MSXMusicBase::readMem(uint16_t address, EmuTime time)
45 
{
46 
	return peekMem(address, time);
47 
}
48
49 
const byte* MSXMusicBase::getReadCacheLine(uint16_t start) const
50 
{
51 
	return &rom[start & (rom.size() - 1)];
52 
}
53
54 
// version 1: initial version
55 
// version 2: refactored YM2413 class structure
56 
// version 3: removed 'registerLatch' (moved to YM2413 cores)
57 
template<typename Archive>
58 
void MSXMusicBase::serialize(Archive& ar, unsigned version)
59 
{
60 
	ar.template serializeBase<MSXDevice>(*this);
61
62 
	if (ar.versionAtLeast(version, 2)) {
63 
		ar.serialize("ym2413", ym2413);
64 
	} else {
65 
		// In older versions, the 'ym2413' level was missing, delegate
66 
		// directly to YM2413 without emitting the 'ym2413' tag.
67 
		ym2413.serialize(ar, version);
68 
	}
69 
}
70 
INSTANTIATE_SERIALIZE_METHODS(MSXMusicBase);
71
72
73
74 
// class MSXMusic
75
76 
MSXMusic::MSXMusic(DeviceConfig& config)
77 
	: MSXMusicBase(config)
78 
{
79 
}
80
81 
template<typename Archive>
82 
void MSXMusic::serialize(Archive& ar, unsigned version)
83 
{
84 
	ar.template serializeInlinedBase<MSXMusicBase>(*this, version);
85 
}
86 
INSTANTIATE_SERIALIZE_METHODS(MSXMusic);
87 
REGISTER_MSXDEVICE(MSXMusic, "MSX-Music");
88
89
90
91 
// class MSXMusicWX
92
93 
// Thanks to NYYRIKKI for figuring this out:
94 
//  - writes to 0x7ff0-0x7fff set a control register (mirrored 16x)
95 
//  - writes to any other memory region have no effect
96 
//  - bit 0 of this control register can be used to disable reading the ROM
97 
//    (0=enable, 1=disabled), other bits seem to have no effect
98 
//  - reading from 0x7ff0-0x7fff return the last written value OR 0xfc, IOW the
99 
//    lower two bits are the last written value, higher bits always read 1
100 
//  - reading from 0x4000-0x7fef returns the content of the ROM if the ROM is
101 
//    enabled (bit 0 of the control register = 0), when the ROM is disabled
102 
//    reads return 0xff
103 
//  - reading any other memory location returns 0xff
104
105 
MSXMusicWX::MSXMusicWX(DeviceConfig& config)
106 
	: MSXMusicBase(config)
107 
{
108 
	reset(getCurrentTime());
109 
}
110
111 
void MSXMusicWX::reset(EmuTime time)
112 
{
113 
	MSXMusicBase::reset(time);
114 
	control = 0;
115 
}
116
117 
byte MSXMusicWX::peekMem(uint16_t address, EmuTime time) const
118 
{
119 
	if ((0x7FF0 <= address) && (address < 0x8000)) {
120 
		return control | 0xFC;
121 
	} else if ((control & 1) == 0) {
122 
		return MSXMusicBase::peekMem(address, time);
123 
	} else {
124 
		return 0xFF;
125 
	}
126 
}
127
128 
byte MSXMusicWX::readMem(uint16_t address, EmuTime time)
129 
{
130 
	return peekMem(address, time);
131 
}
132
133 
const byte* MSXMusicWX::getReadCacheLine(uint16_t start) const
134 
{
135 
	if ((0x7FF0 & CacheLine::HIGH) == start) {
136 
		return nullptr;
137 
	} else if ((control & 1) == 0) {
138 
		return MSXMusicBase::getReadCacheLine(start);
139 
	} else {
140 
		return unmappedRead.data();
141 
	}
142 
}
143
144 
void MSXMusicWX::writeMem(uint16_t address, byte value, EmuTime /*time*/)
145 
{
146 
	if ((0x7FF0 <= address) && (address < 0x8000)) {
147 
		control = value & 3;
148 
		invalidateDeviceRCache();
149 
	}
150 
}
151
152 
byte* MSXMusicWX::getWriteCacheLine(uint16_t start)
153 
{
154 
	if ((0x7FF0 & CacheLine::HIGH) == start) {
155 
		return nullptr;
156 
	} else {
157 
		return unmappedWrite.data();
158 
	}
159 
}
160
161 
template<typename Archive>
162 
void MSXMusicWX::serialize(Archive& ar, unsigned version)
163 
{
164 
	ar.template serializeInlinedBase<MSXMusicBase>(*this, version);
165 
	ar.serialize("control", control);
166 
}
167 
INSTANTIATE_SERIALIZE_METHODS(MSXMusicWX);
168 
REGISTER_MSXDEVICE(MSXMusicWX, "MSX-Music-WX");
169
170 
} // namespace openmsx