src/fdc/YamahaFDC.cc at main · doomsdayone/openmsx

◆ main openmsx / src / fdc / YamahaFDC.cc

5.9 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw

#include "YamahaFDC.hh"

#include "DriveMultiplexer.hh"
#include "WD2793.hh"

#include "CacheLine.hh"
#include "MSXException.hh"
#include "Rom.hh"
#include "serialize.hh"

#include "one_of.hh"

// This is derived by disassembly of the Yamaha FD-03 disk rom
//   https://sourceforge.net/p/msxsyssrc/git/ci/master/tree/diskdrvs/fd-03/
//
// FDD interface:
// 7FC0   I/O            FDC STATUS/COMMAND
// 7FC1   I/O            FDC TRACK REGISTER
// 7FC2   I/O            FDC SECTOR REGISTER
// 7FC3   I/O            FDC DATA REGISTER
// 7FE0   O     bit 0    SELECT DRIVE A              "1" ON
//        I     bit 0    READY DRIVE A               "0" READY, "1" NOT READY
//        O     bit 1    SELECT DRIVE B              "1" ON
//        I     bit 1    READY DRIVE B               "0" READY, "1" NOT READY
//        O     bit 2    MOTOR                       "1" ON
//        I     bit 2    DISK CHANGE DRIVE A         "1" CHANGED
//        O     bit 3    UNKNOWN FUNCTION
//        I     bit 3    DISK CHANGE DRIVE B         "1" CHANGED
//        I     bit 6    FDC DATA REQUEST            "1" REQUEST
//        I     bit 7    FDC INTERRUPT REQUEST       "1" REQUEST
//
// 7FF0   O              RESET DISK CHANGE DRIVE A
//        I              RESET DISK CHANGE DRIVE B

namespace openmsx {

static constexpr int DRIVE_A_SELECT = 0x01;
static constexpr int DRIVE_B_SELECT = 0x02;
static constexpr int DRIVE_A_NOT_READY = 0x01;
static constexpr int DRIVE_B_NOT_READY = 0x02;
static constexpr int DISK_A_CHANGED = 0x04;
static constexpr int DISK_B_CHANGED = 0x08;
static constexpr int MOTOR_ON = 0x04;
static constexpr int DATA_REQUEST  = 0x40;
static constexpr int INTR_REQUEST  = 0x80;


YamahaFDC::YamahaFDC(DeviceConfig& config)
	: WD2793BasedFDC(config, "", true, DiskDrive::TrackMode::YAMAHA_FD_03)
{
	if (rom->size() != one_of(0x4000u, 0x8000u)) {
		throw MSXException("YamahaFDC ROM size must be 16kB or 32kB.");
	}
	reset(getCurrentTime());
}

void YamahaFDC::reset(EmuTime time)
{
	WD2793BasedFDC::reset(time);
	writeMem(0x7FE0, 0x00, time);
}

byte YamahaFDC::readMem(uint16_t address, EmuTime time)
{
	switch (address & 0x3FFF) {
	case 0x3FC0:
		return controller.getStatusReg(time);
	case 0x3FC1:
		return controller.getTrackReg(time);
	case 0x3FC2:
		return controller.getSectorReg(time);
	case 0x3FC3:
		return controller.getDataReg(time);
	case 0x3FE0: {
		byte value = 0;
		if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::A)) value |= DRIVE_A_NOT_READY;
		if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::B)) value |= DRIVE_B_NOT_READY;
		// note: peekDiskChanged() instead of diskChanged() because we don't want an implicit reset
		if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::A)) value |= DISK_A_CHANGED;
		if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::B)) value |= DISK_B_CHANGED;
		if (controller.getIRQ(time))  value |= INTR_REQUEST;
		if (controller.getDTRQ(time)) value |= DATA_REQUEST;
		return value;
	}
	case 0x3FF0:
		multiplexer.diskChanged(DriveMultiplexer::Drive::B); // clear
		[[fallthrough]];
	default:
		return peekMem(address, time);
	}
}

byte YamahaFDC::peekMem(uint16_t address, EmuTime time) const
{
	switch (address & 0x3FFF) {
	case 0x3FC0:
		return controller.peekStatusReg(time);
	case 0x3FC1:
		return controller.peekTrackReg(time);
	case 0x3FC2:
		return controller.peekSectorReg(time);
	case 0x3FC3:
		return controller.peekDataReg(time);
	case 0x3FE0: {
		byte value = 0;
		if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::A)) value |= DRIVE_A_NOT_READY;
		if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::B)) value |= DRIVE_B_NOT_READY;
		if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::A)) value |= DISK_A_CHANGED;
		if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::B)) value |= DISK_B_CHANGED;
		if (controller.peekIRQ(time))  value |= INTR_REQUEST;
		if (controller.peekDTRQ(time)) value |= DATA_REQUEST;
		return value;
	}
	case 0x3FF0:
		// don't clear on peek
		[[fallthrough]];
	default:
		if (unsigned(address - 0x4000) < rom->size()) {
			return (*rom)[address - 0x4000];
		} else {
			return 255;
		}
	}
}

const byte* YamahaFDC::getReadCacheLine(uint16_t start) const
{
	if ((start & 0x3FFF & CacheLine::HIGH) == (0x3FC0 & CacheLine::HIGH)) {
		// FDC at 0x7FC0-0x7FFF  or  0xBFC0-0xBFFF
		return nullptr;
	} else if (unsigned(start - 0x4000) < rom->size()) {
		return &(*rom)[start - 0x4000];
	} else {
		return unmappedRead.data();
	}
}

void YamahaFDC::writeMem(uint16_t address, byte value, EmuTime time)
{
	switch (address & 0x3fff) {
	case 0x3FC0:
		controller.setCommandReg(value, time);
		break;
	case 0x3FC1:
		controller.setTrackReg(value, time);
		break;
	case 0x3FC2:
		controller.setSectorReg(value, time);
		break;
	case 0x3FC3:
		controller.setDataReg(value, time);
		break;
	case 0x3FE0: {
		auto drive = [&] {
			switch (value & (DRIVE_A_SELECT | DRIVE_B_SELECT)) {
			case DRIVE_A_SELECT:
				return DriveMultiplexer::Drive::A;
			case DRIVE_B_SELECT:
				return DriveMultiplexer::Drive::B;
			default:
				// No drive selected or two drives at same time
				// The motor is enabled for all drives at the same time, so
				// in a real machine you must take care to do not select more
				// than one drive at the same time (you could get data
				// collision).
				return DriveMultiplexer::Drive::NONE;
			}
		}();
		multiplexer.selectDrive(drive, time);
		multiplexer.setSide(false);
		multiplexer.setMotor((value & MOTOR_ON) != 0, time);
		break;
	}
	case 0x3FF0:
		multiplexer.diskChanged(DriveMultiplexer::Drive::A);
		break;
	}
}

byte* YamahaFDC::getWriteCacheLine(uint16_t address)
{
	if ((address & 0x3FFF & CacheLine::HIGH) == (0x3FC0 & CacheLine::HIGH)) {
		// FDC at 0x7FC0-0x7FFF  or  0xBFC0-0xBFFF
		return nullptr;
	} else {
		return unmappedWrite.data();
	}
}

template<typename Archive>
void YamahaFDC::serialize(Archive& ar, unsigned /*version*/)
{
	ar.template serializeBase<WD2793BasedFDC>(*this);
}
INSTANTIATE_SERIALIZE_METHODS(YamahaFDC);
REGISTER_MSXDEVICE(YamahaFDC, "YamahaFDC");

} // namespace openmsx

1	#include "YamahaFDC.hh"
2
3	#include "DriveMultiplexer.hh"
4	#include "WD2793.hh"
5
6	#include "CacheLine.hh"
7	#include "MSXException.hh"
8	#include "Rom.hh"
9	#include "serialize.hh"
10
11	#include "one_of.hh"
12
13	// This is derived by disassembly of the Yamaha FD-03 disk rom
14	// https://sourceforge.net/p/msxsyssrc/git/ci/master/tree/diskdrvs/fd-03/
15	//
16	// FDD interface:
17	// 7FC0 I/O FDC STATUS/COMMAND
18	// 7FC1 I/O FDC TRACK REGISTER
19	// 7FC2 I/O FDC SECTOR REGISTER
20	// 7FC3 I/O FDC DATA REGISTER
21	// 7FE0 O bit 0 SELECT DRIVE A "1" ON
22	// I bit 0 READY DRIVE A "0" READY, "1" NOT READY
23	// O bit 1 SELECT DRIVE B "1" ON
24	// I bit 1 READY DRIVE B "0" READY, "1" NOT READY
25	// O bit 2 MOTOR "1" ON
26	// I bit 2 DISK CHANGE DRIVE A "1" CHANGED
27	// O bit 3 UNKNOWN FUNCTION
28	// I bit 3 DISK CHANGE DRIVE B "1" CHANGED
29	// I bit 6 FDC DATA REQUEST "1" REQUEST
30	// I bit 7 FDC INTERRUPT REQUEST "1" REQUEST
31	//
32	// 7FF0 O RESET DISK CHANGE DRIVE A
33	// I RESET DISK CHANGE DRIVE B
34
35	namespace openmsx {
36
37	static constexpr int DRIVE_A_SELECT = 0x01;
38	static constexpr int DRIVE_B_SELECT = 0x02;
39	static constexpr int DRIVE_A_NOT_READY = 0x01;
40	static constexpr int DRIVE_B_NOT_READY = 0x02;
41	static constexpr int DISK_A_CHANGED = 0x04;
42	static constexpr int DISK_B_CHANGED = 0x08;
43	static constexpr int MOTOR_ON = 0x04;
44	static constexpr int DATA_REQUEST = 0x40;
45	static constexpr int INTR_REQUEST = 0x80;
46
47
48	YamahaFDC::YamahaFDC(DeviceConfig& config)
49	: WD2793BasedFDC(config, "", true, DiskDrive::TrackMode::YAMAHA_FD_03)
50	{
51	if (rom->size() != one_of(0x4000u, 0x8000u)) {
52	throw MSXException("YamahaFDC ROM size must be 16kB or 32kB.");
53	}
54	reset(getCurrentTime());
55	}
56
57	void YamahaFDC::reset(EmuTime time)
58	{
59	WD2793BasedFDC::reset(time);
60	writeMem(0x7FE0, 0x00, time);
61	}
62
63	byte YamahaFDC::readMem(uint16_t address, EmuTime time)
64	{
65	switch (address & 0x3FFF) {
66	case 0x3FC0:
67	return controller.getStatusReg(time);
68	case 0x3FC1:
69	return controller.getTrackReg(time);
70	case 0x3FC2:
71	return controller.getSectorReg(time);
72	case 0x3FC3:
73	return controller.getDataReg(time);
74	case 0x3FE0: {
75	byte value = 0;
76	if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::A)) value \|= DRIVE_A_NOT_READY;
77	if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::B)) value \|= DRIVE_B_NOT_READY;
78	// note: peekDiskChanged() instead of diskChanged() because we don't want an implicit reset
79	if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::A)) value \|= DISK_A_CHANGED;
80	if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::B)) value \|= DISK_B_CHANGED;
81	if (controller.getIRQ(time)) value \|= INTR_REQUEST;
82	if (controller.getDTRQ(time)) value \|= DATA_REQUEST;
83	return value;
84	}
85	case 0x3FF0:
86	multiplexer.diskChanged(DriveMultiplexer::Drive::B); // clear
87	[[fallthrough]];
88	default:
89	return peekMem(address, time);
90	}
91	}
92
93	byte YamahaFDC::peekMem(uint16_t address, EmuTime time) const
94	{
95	switch (address & 0x3FFF) {
96	case 0x3FC0:
97	return controller.peekStatusReg(time);
98	case 0x3FC1:
99	return controller.peekTrackReg(time);
100	case 0x3FC2:
101	return controller.peekSectorReg(time);
102	case 0x3FC3:
103	return controller.peekDataReg(time);
104	case 0x3FE0: {
105	byte value = 0;
106	if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::A)) value \|= DRIVE_A_NOT_READY;
107	if (!multiplexer.isDiskInserted(DriveMultiplexer::Drive::B)) value \|= DRIVE_B_NOT_READY;
108	if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::A)) value \|= DISK_A_CHANGED;
109	if (multiplexer.peekDiskChanged(DriveMultiplexer::Drive::B)) value \|= DISK_B_CHANGED;
110	if (controller.peekIRQ(time)) value \|= INTR_REQUEST;
111	if (controller.peekDTRQ(time)) value \|= DATA_REQUEST;
112	return value;
113	}
114	case 0x3FF0:
115	// don't clear on peek
116	[[fallthrough]];
117	default:
118	if (unsigned(address - 0x4000) < rom->size()) {
119	return (*rom)[address - 0x4000];
120	} else {
121	return 255;
122	}
123	}
124	}
125
126	const byte* YamahaFDC::getReadCacheLine(uint16_t start) const
127	{
128	if ((start & 0x3FFF & CacheLine::HIGH) == (0x3FC0 & CacheLine::HIGH)) {
129	// FDC at 0x7FC0-0x7FFF or 0xBFC0-0xBFFF
130	return nullptr;
131	} else if (unsigned(start - 0x4000) < rom->size()) {
132	return &(*rom)[start - 0x4000];
133	} else {
134	return unmappedRead.data();
135	}
136	}
137
138	void YamahaFDC::writeMem(uint16_t address, byte value, EmuTime time)
139	{
140	switch (address & 0x3fff) {
141	case 0x3FC0:
142	controller.setCommandReg(value, time);
143	break;
144	case 0x3FC1:
145	controller.setTrackReg(value, time);
146	break;
147	case 0x3FC2:
148	controller.setSectorReg(value, time);
149	break;
150	case 0x3FC3:
151	controller.setDataReg(value, time);
152	break;
153	case 0x3FE0: {
154	auto drive = [&] {
155	switch (value & (DRIVE_A_SELECT \| DRIVE_B_SELECT)) {
156	case DRIVE_A_SELECT:
157	return DriveMultiplexer::Drive::A;
158	case DRIVE_B_SELECT:
159	return DriveMultiplexer::Drive::B;
160	default:
161	// No drive selected or two drives at same time
162	// The motor is enabled for all drives at the same time, so
163	// in a real machine you must take care to do not select more
164	// than one drive at the same time (you could get data
165	// collision).
166	return DriveMultiplexer::Drive::NONE;
167	}
168	}();
169	multiplexer.selectDrive(drive, time);
170	multiplexer.setSide(false);
171	multiplexer.setMotor((value & MOTOR_ON) != 0, time);
172	break;
173	}
174	case 0x3FF0:
175	multiplexer.diskChanged(DriveMultiplexer::Drive::A);
176	break;
177	}
178	}
179
180	byte* YamahaFDC::getWriteCacheLine(uint16_t address)
181	{
182	if ((address & 0x3FFF & CacheLine::HIGH) == (0x3FC0 & CacheLine::HIGH)) {
183	// FDC at 0x7FC0-0x7FFF or 0xBFC0-0xBFFF
184	return nullptr;
185	} else {
186	return unmappedWrite.data();
187	}
188	}
189
190	template<typename Archive>
191	void YamahaFDC::serialize(Archive& ar, unsigned /version/)
192	{
193	ar.template serializeBase<WD2793BasedFDC>(*this);
194	}
195	INSTANTIATE_SERIALIZE_METHODS(YamahaFDC);
196	REGISTER_MSXDEVICE(YamahaFDC, "YamahaFDC");
197
198	} // namespace openmsx

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