summaryrefslogtreecommitdiffstatshomepage
path: root/src/devices/video/tms9927.cpp
blob: bc8e187f8e896512d90b8afb973919b03ce3c562 (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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/**********************************************************************

    TI TMS9927 and compatible CRT controller emulation

**********************************************************************/

#include "emu.h"
#include "video/tms9927.h"

#include "screen.h"


static constexpr uint8_t chars_per_row_value[8] = { 20, 32, 40, 64, 72, 80, 96, 132 };
static constexpr uint8_t skew_bits_value[4] = { 0, 1, 2, 2 };


#define HCOUNT               (m_reg[0] + 1)
#define INTERLACED           ((m_reg[1] >> 7) & 0x01)
#define HSYNC_WIDTH          (((m_reg[1] >> 3) & 0x0f) + 1)
#define HSYNC_DELAY          (((m_reg[1] >> 0) & 0x07) + 1)
#define SCANS_PER_DATA_ROW   (((m_reg[2] >> 3) & 0x0f) + 1)
#define CHARS_PER_DATA_ROW   (chars_per_row_value[(m_reg[2] >> 0) & 0x07])
#define SKEW_BITS            (skew_bits_value[(m_reg[3] >> 6) & 0x03])
#define DATA_ROWS_PER_FRAME  ((m_reg[3] & 0x3f) + 1)
#define SCAN_LINES_PER_FRAME ((m_reg[4] * 2) + 256 + (((m_reg[1] >> 7) & 0x01) * 257))
#define VERTICAL_DATA_START  (m_reg[5])
#define LAST_DISP_DATA_ROW   (m_reg[6] & 0x3f)
#define CURSOR_CHAR_ADDRESS  (m_reg[7])
#define CURSOR_ROW_ADDRESS   (m_reg[8] & 0x3f)


DEFINE_DEVICE_TYPE(TMS9927, tms9927_device, "tms9927", "TMS9927 VTC")
DEFINE_DEVICE_TYPE(CRT5027, crt5027_device, "crt5027", "CRT5027 VTAC")
DEFINE_DEVICE_TYPE(CRT5037, crt5037_device, "crt5037", "CRT5037 VTAC")
DEFINE_DEVICE_TYPE(CRT5057, crt5057_device, "crt5057", "CRT5057 VTAC")

tms9927_device::tms9927_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: tms9927_device(mconfig, TMS9927, tag, owner, clock)
{
}

tms9927_device::tms9927_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock)
	: device_t(mconfig, type, tag, owner, clock)
	, device_video_interface(mconfig, *this)
	, m_write_vsyn(*this)
	, m_write_hsyn(*this)
	, m_hpixels_per_column(0)
	, m_overscan_left(0)
	, m_overscan_right(0)
	, m_overscan_top(0)
	, m_overscan_bottom(0)
	, m_selfload(*this, finder_base::DUMMY_TAG)
	, m_reset(false)
	, m_valid_config(false)
{
	std::fill(std::begin(m_reg), std::end(m_reg), 0x00);
}

crt5027_device::crt5027_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: tms9927_device(mconfig, CRT5027, tag, owner, clock)
{
}

crt5037_device::crt5037_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: tms9927_device(mconfig, CRT5037, tag, owner, clock)
{
}

crt5057_device::crt5057_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: tms9927_device(mconfig, CRT5057, tag, owner, clock)
{
}


//-------------------------------------------------
//  device_start - device-specific startup
//-------------------------------------------------

void tms9927_device::device_start()
{
	assert(clock() > 0);
	if (!(m_hpixels_per_column > 0)) fatalerror("TMS9927: number of pixels per column must be explicitly set using set_char_width()!\n");

	// resolve callbacks
	m_write_vsyn.resolve_safe();
	m_write_hsyn.resolve();

	// allocate timers
	m_vsync_timer = timer_alloc(TIMER_VSYNC);
	m_hsync_timer = timer_alloc(TIMER_HSYNC);

	// register for state saving
	save_item(NAME(m_reg));
	save_item(NAME(m_start_datarow));
	save_item(NAME(m_reset));
	save_item(NAME(m_vsyn));
	save_item(NAME(m_hsyn));
}

//-------------------------------------------------
//  device_reset - device-specific reset
//-------------------------------------------------

void tms9927_device::device_reset()
{
	m_start_datarow = 0;
}

//-------------------------------------------------
//  device_clock_changed - called when the
//  device clock is altered in any way
//-------------------------------------------------

void tms9927_device::device_clock_changed()
{
	if (m_valid_config && !m_reset)
		recompute_parameters(false);
}

//-------------------------------------------------
//  device_stop - device-specific stop
//-------------------------------------------------

void tms9927_device::device_stop()
{
	osd_printf_debug("TMS9927: Final params: (%d, %d, %d, %d, %d, %d, %d)\n",
						clock() * m_hpixels_per_column,
						m_total_hpix,
						0, m_visible_hpix,
						m_total_vpix,
						0, m_visible_vpix);
}



//-------------------------------------------------
//  device_timer - handle timer events
//-------------------------------------------------

void tms9927_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
	switch (id)
	{
	case TIMER_VSYNC:
		m_vsyn = !m_vsyn;
		m_write_vsyn(m_vsyn ? 1 : 0);

		if (m_vsyn)
		{
			m_vsync_timer->adjust(screen().time_until_pos(m_vsyn_end, m_hsyn_start));
		}
		else
		{
			m_vsync_timer->adjust(screen().time_until_pos(m_vsyn_start, m_hsyn_start));
		}
		break;

	case TIMER_HSYNC:
		m_hsyn = !m_hsyn;
		m_write_hsyn(m_hsyn ? 1 : 0);

		uint16_t vpos = screen().vpos();
		if (m_hsyn)
		{
			screen().update_now();
			if (screen().hpos() > m_hsyn_end)
				vpos = (vpos + 1) % m_total_vpix;
			m_hsync_timer->adjust(screen().time_until_pos(vpos, m_hsyn_end));
		}
		else
		{
			if (screen().hpos() > m_hsyn_start)
				vpos = (vpos + 1) % m_total_vpix;
			m_hsync_timer->adjust(screen().time_until_pos(vpos, m_hsyn_start));
		}
		break;
	}
}

void tms9927_device::device_post_load()
{
	recompute_parameters(true);
}


void tms9927_device::generic_access(address_space &space, offs_t offset)
{
	switch (offset)
	{
		case 0x07:  /* Processor Self Load */
		case 0x0f:  /* Non-processor self-load */
			if (m_selfload.found())
			{
				for (int cur = 0; cur < 7; cur++)
					write(space, cur, m_selfload[cur]);
				for (int cur = 0; cur < 1; cur++)
					write(space, cur + 0xc, m_selfload[cur + 7]);
			}
			else
				popmessage("tms9927: self-load initiated with no PROM!");

			/* processor self-load waits with reset enabled;
			   non-processor just goes ahead */
			m_reset = (offset == 0x07);
			break;

		case 0x0a:  /* Reset */
			if (!m_reset)
			{
				screen().update_now();
				m_reset = true;
			}
			break;

		case 0x0b:  /* Up scroll */
			screen().update_now();
			m_start_datarow = (m_start_datarow + 1) % DATA_ROWS_PER_FRAME;
			break;

		case 0x0e:  /* Start timing chain */
			if (m_reset)
			{
				screen().update_now();
				m_reset = false;
				recompute_parameters(false);
			}
			break;
	}
}

WRITE8_MEMBER( tms9927_device::write )
{
	switch (offset)
	{
		case 0x00:  /* HORIZONTAL CHARACTER COUNT */
		case 0x01:  /* INTERLACED / HSYNC WIDTH / HSYNC DELAY */
		case 0x02:  /* SCANS PER DATA ROW / CHARACTERS PER DATA ROW */
		case 0x03:  /* SKEW BITS / DATA ROWS PER FRAME */
		case 0x04:  /* SCAN LINES / FRAME */
		case 0x05:  /* VERTICAL DATA START */
			m_reg[offset] = data;
			recompute_parameters(false);
			break;

		case 0x06:  /* LAST DISPLAYED DATA ROW */
			// TVI-912 writes to this register frequently
			if (m_reg[offset] != data)
			{
				m_reg[offset] = data;
				recompute_parameters(false);
			}
			break;

		case 0x0c:  /* LOAD CURSOR CHARACTER ADDRESS */
		case 0x0d:  /* LOAD CURSOR ROW ADDRESS */
			m_reg[offset - 0x0c + 7] = data;
			/* Recomputing parameters here will break the scrollup on the Attachè
			   and probably other machines due to m_start_datarow being reset ! */
			//recompute_parameters(false);
			break;

		default:
			generic_access(space, offset);
			break;
	}
}


READ8_MEMBER( tms9927_device::read )
{
	switch (offset)
	{
		case 0x08:  /* READ CURSOR CHARACTER ADDRESS */
		case 0x09:  /* READ CURSOR ROW ADDRESS */
			return m_reg[offset - 0x08 + 7];

		default:
			if (!machine().side_effects_disabled())
				generic_access(space, offset);
			break;
	}
	return 0xff;
}


READ_LINE_MEMBER(tms9927_device::bl_r)
{
	return (m_reset || screen().vblank() || screen().hblank()) ? 1 : 0;
}


bool tms9927_device::cursor_bounds(rectangle &bounds) const
{
	int cursorx = CURSOR_CHAR_ADDRESS;
	int cursory = (CURSOR_ROW_ADDRESS + DATA_ROWS_PER_FRAME - m_start_datarow) % DATA_ROWS_PER_FRAME;

	bounds.min_x = cursorx * m_hpixels_per_column;
	bounds.max_x = bounds.min_x + m_hpixels_per_column - 1;
	bounds.min_y = cursory * SCANS_PER_DATA_ROW;
	bounds.max_y = bounds.min_y + SCANS_PER_DATA_ROW - 1;

	return (cursorx < HCOUNT && cursory <= LAST_DISP_DATA_ROW);
}


void tms9927_device::recompute_parameters(bool postload)
{
	if (m_reset)
		return;

	/* compute the screen sizes */
	m_total_hpix = HCOUNT * m_hpixels_per_column;
	m_total_vpix = SCAN_LINES_PER_FRAME;

	/* determine the visible area, avoid division by 0 */
	m_visible_hpix = CHARS_PER_DATA_ROW * m_hpixels_per_column;
	m_visible_vpix = DATA_ROWS_PER_FRAME * SCANS_PER_DATA_ROW;

	m_start_datarow = (LAST_DISP_DATA_ROW + 1) % DATA_ROWS_PER_FRAME;

	m_hsyn_start = (m_visible_hpix + m_overscan_left + HSYNC_DELAY * m_hpixels_per_column) % m_total_hpix;
	m_hsyn_end = (m_hsyn_start + HSYNC_WIDTH * m_hpixels_per_column) % m_total_hpix;

	m_vsyn_start = (m_total_vpix + m_overscan_top - VERTICAL_DATA_START) % m_total_vpix;
	m_vsyn_end = (m_vsyn_start + 3) % m_total_vpix;

	/* see if it all makes sense */
	m_valid_config = true;
	if ( (m_visible_hpix > m_total_hpix || m_visible_vpix > m_total_vpix) || (((m_visible_hpix-1)<=0) || ((m_visible_vpix-1)<=0)) || ((m_total_hpix * m_total_vpix) == 0) )
	{
		m_valid_config = false;
		logerror("tms9927: invalid visible size (%dx%d) versus total size (%dx%d)\n", m_visible_hpix, m_visible_vpix, m_total_hpix, m_total_vpix);
	}

	if (clock() == 0)
	{
		m_valid_config = false;
		// TODO: make the screen refresh never, and disable the vblank and odd/even interrupts here!
		logerror("tms9927: invalid clock rate of zero defined!\n");
	}

	/* update */
	if (!m_valid_config)
		return;

	/* create a visible area */
	rectangle visarea(0, m_overscan_left + m_visible_hpix + m_overscan_right - 1,
				0, m_overscan_top + m_visible_vpix + m_overscan_bottom - 1);

	attotime refresh = clocks_to_attotime(HCOUNT * m_total_vpix);

	osd_printf_debug("TMS9927: Total = %dx%d, Visible = %dx%d, HSync = %d-%d, VSync = %d-%d, Skew=%d, Upscroll=%d, Period=%f Hz\n", m_total_hpix, m_total_vpix, m_visible_hpix, m_visible_vpix, m_hsyn_start, m_hsyn_end, m_vsyn_start, m_vsyn_end, SKEW_BITS, m_start_datarow, refresh.as_hz());

	screen().configure(m_total_hpix, m_total_vpix, visarea, refresh.as_attoseconds());

	m_hsyn = false;
	if (!m_write_hsyn.isnull())
	{
		m_write_hsyn(0);
		m_hsync_timer->adjust(screen().time_until_pos(m_vsyn_start, m_hsyn_start));
	}

	m_vsyn = false;
	m_write_vsyn(0);
	m_vsync_timer->adjust(screen().time_until_pos(m_vsyn_start, m_hsyn_start));
}