summaryrefslogtreecommitdiffstatshomepage
path: root/src/emu/bus/iq151/video64.c
blob: 93720651c8feabd57c10f8e16367109e01f16172 (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
// license:BSD-3-Clause
// copyright-holders:Sandro Ronco
/***************************************************************************

    IQ151 video64 cartridge emulation

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

#include "emu.h"
#include "video64.h"


/***************************************************************************
    IMPLEMENTATION
***************************************************************************/

ROM_START( iq151_video64 )
	ROM_REGION(0x0800, "chargen", ROMREGION_INVERT)
	ROM_LOAD( "iq151_video64font.rom", 0x0000, 0x0800, CRC(cb6f43c0) SHA1(4b2c1d41838d569228f61568c1a16a8d68b3dadf))

	ROM_REGION(0x0800, "videoram", ROMREGION_ERASE)
ROM_END


/* F4 Character Displayer */
static const gfx_layout iq151_video64_charlayout =
{
	6, 8,                   /* 6 x 8 characters */
	256,                    /* 256 characters */
	1,                  /* 1 bits per pixel */
	{ 0 },                  /* no bitplanes */
	/* x offsets */
	{ 2, 3, 4, 5, 6, 7 },
	/* y offsets */
	{ 0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8 },
	8*8                 /* every char takes 8 bytes */
};

static GFXDECODE_START( video64 )
GFXDECODE_END

static MACHINE_CONFIG_FRAGMENT( video64 )
	MCFG_GFXDECODE_ADD("gfxdecode", video64)
MACHINE_CONFIG_END

//**************************************************************************
//  GLOBAL VARIABLES
//**************************************************************************

const device_type IQ151_VIDEO64 = &device_creator<iq151_video64_device>;

//**************************************************************************
//  LIVE DEVICE
//**************************************************************************

//-------------------------------------------------
//  iq151_video64_device - constructor
//-------------------------------------------------

iq151_video64_device::iq151_video64_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
		: device_t(mconfig, IQ151_VIDEO64, "IQ151 video64", tag, owner, clock, "iq151_video64", __FILE__),
		device_iq151cart_interface( mconfig, *this ),
		m_gfxdecode(*this, "gfxdecode"),
		m_palette(*this, ":palette")
{
}

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

void iq151_video64_device::device_start()
{
	m_videoram = (UINT8*)memregion("videoram")->base();
	m_chargen = (UINT8*)memregion("chargen")->base();

	m_gfxdecode->set_gfx(0,global_alloc(gfx_element(m_palette, iq151_video64_charlayout, m_chargen, 1, 0)));
}

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

void iq151_video64_device::device_reset()
{
	screen_device *screen = machine().primary_screen;

	// if required adjust screen size
	if (screen->visible_area().max_x < 64*6 - 1)
		screen->set_visible_area(0, 64*6-1, 0, 32*8-1);
}

//-------------------------------------------------
//  machine_config_additions - device-specific
//  machine configurations
//-------------------------------------------------

machine_config_constructor iq151_video64_device::device_mconfig_additions() const
{
	return MACHINE_CONFIG_NAME( video64 );
}

//-------------------------------------------------
//  device_rom_region
//-------------------------------------------------

const rom_entry *iq151_video64_device::device_rom_region() const
{
	return ROM_NAME( iq151_video64 );
}

//-------------------------------------------------
//  read
//-------------------------------------------------

void iq151_video64_device::read(offs_t offset, UINT8 &data)
{
	// videoram is mapped at 0xe800-0xefff
	if (offset >= 0xe800 && offset < 0xf000)
		data = m_videoram[offset & 0x7ff];
}

//-------------------------------------------------
//  write
//-------------------------------------------------

void iq151_video64_device::write(offs_t offset, UINT8 data)
{
	if (offset >= 0xe800 && offset < 0xf000)
		m_videoram[offset & 0x7ff] = data;
}

//-------------------------------------------------
//  IO read
//-------------------------------------------------

void iq151_video64_device::io_read(offs_t offset, UINT8 &data)
{
	if (offset >= 0xfc && offset < 0x100)
	{
		// this value is used by the IQ151 for detect if the installed
		// cart is video64 or video32
		data = 0xfe;
	}
}

//-------------------------------------------------
//  video update
//-------------------------------------------------

void iq151_video64_device::video_update(bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	UINT16 ma = 0, sy = 0;

	for (int y = 0; y < 32; y++)
	{
		for (int ra = 0; ra < 8; ra++)
		{
			UINT16 *p = &bitmap.pix16(sy++);

			for (int x = ma; x < ma + 64; x++)
			{
				UINT8 chr = m_videoram[x];
				UINT8 gfx = m_chargen[(chr<<3) | ra ];

				/* Display a scanline of a character */
				*p++ |= BIT(gfx, 5);
				*p++ |= BIT(gfx, 4);
				*p++ |= BIT(gfx, 3);
				*p++ |= BIT(gfx, 2);
				*p++ |= BIT(gfx, 1);
				*p++ |= BIT(gfx, 0);
			}
		}
		ma += 64;
	}
}