1 // license:BSD-3-Clause
2 // copyright-holders:Philip Bennett
3 /***************************************************************************
4
5 Turret Tower sound hardware
6
7 ****************************************************************************/
8
9 #include "emu.h"
10 #include "includes/turrett.h"
11
12 DEFINE_DEVICE_TYPE(TURRETT, turrett_device, "ttsnd", "Turret Tower Sound")
13
14
15 //-------------------------------------------------
16 // turrett_device - constructor
17 //-------------------------------------------------
18
turrett_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)19 turrett_device::turrett_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
20 : device_t(mconfig, TURRETT, tag, owner, clock)
21 , device_sound_interface(mconfig, *this)
22 , device_memory_interface(mconfig, *this)
23 , m_space_config("ttsound", ENDIANNESS_LITTLE, 16, 28, 0)
24 {
25 }
26
27
28 //-------------------------------------------------
29 // memory_space_config - configure address space
30 //-------------------------------------------------
31
memory_space_config() const32 device_memory_interface::space_config_vector turrett_device::memory_space_config() const
33 {
34 return space_config_vector {
35 std::make_pair(0, &m_space_config)
36 };
37 }
38
39
40 //-------------------------------------------------
41 // device_start - initialize the device
42 //-------------------------------------------------
43
device_start()44 void turrett_device::device_start()
45 {
46 // Find our direct access
47 space().cache(m_cache);
48
49 // Create the sound stream
50 m_stream = stream_alloc(0, 2, 44100);
51
52 // Create the volume table
53 for (int i = 0; i < 0x4f; ++i)
54 m_volume_table[i] = 65536 * powf(2.0, (-0.375/4) * i);
55
56 // Last entry is effectively mute
57 m_volume_table[0x4f] = 0;
58
59 // Register state for saving
60 for (int ch = 0; ch < SOUND_CHANNELS; ++ch)
61 {
62 save_item(NAME(m_channels[ch].m_address), ch);
63 save_item(NAME(m_channels[ch].m_volume), ch);
64 save_item(NAME(m_channels[ch].m_playing), ch);
65 }
66 }
67
68
69 //-------------------------------------------------
70 // device_reset - reset the device
71 //-------------------------------------------------
72
device_reset()73 void turrett_device::device_reset()
74 {
75 for (auto & elem : m_channels)
76 elem.m_playing = false;
77 }
78
79
80 //-------------------------------------------------
81 // sound_stream_update - update sound stream
82 //-------------------------------------------------
83
sound_stream_update(sound_stream & stream,std::vector<read_stream_view> const & inputs,std::vector<write_stream_view> & outputs)84 void turrett_device::sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs)
85 {
86 // Silence the buffers
87 outputs[0].fill(0);
88 outputs[1].fill(0);
89
90 for (int ch = 0; ch < SOUND_CHANNELS; ++ch)
91 {
92 if (m_channels[ch].m_playing)
93 {
94 uint32_t &addr = m_channels[ch].m_address;
95 int32_t lvol = (m_channels[ch].m_volume >> 16) & 0xff;
96 int32_t rvol = m_channels[ch].m_volume & 0xff;
97
98 lvol = m_volume_table[lvol];
99 rvol = m_volume_table[rvol];
100
101 // Channels 30 and 31 expect interleaved stereo samples
102 uint32_t incr = (ch >= 30) ? 2 : 1;
103
104 for (int s = 0; s < outputs[0].samples(); ++s)
105 {
106 int16_t sample = m_cache.read_word(addr << 1);
107
108 if ((uint16_t)sample == 0x8000)
109 {
110 m_channels[ch].m_playing = false;
111 break;
112 }
113
114 addr += incr;
115
116 outputs[0].add_int(s, (sample * lvol) >> 17, 32768);
117 outputs[1].add_int(s, (sample * rvol) >> 17, 32768);
118 }
119 }
120 }
121 }
122
123
124 //-------------------------------------------------
125 // read - host CPU read access
126 //-------------------------------------------------
127
read(offs_t offset)128 uint32_t turrett_device::read(offs_t offset)
129 {
130 m_stream->update();
131
132 int ch = offset & 0x3f;
133
134 return m_channels[ch].m_playing << 31;
135 }
136
137
138 //-------------------------------------------------
139 // write - host CPU write access
140 //-------------------------------------------------
141
write(offs_t offset,uint32_t data)142 void turrett_device::write(offs_t offset, uint32_t data)
143 {
144 m_stream->update();
145
146 int ch = offset & 0x3f;
147
148 if (offset < 0x100/4)
149 {
150 if (data == 0)
151 {
152 m_channels[ch].m_playing = false;
153 }
154 else
155 {
156 m_channels[ch].m_address = data;
157 m_channels[ch].m_playing = true;
158 }
159 }
160 else
161 {
162 m_channels[ch].m_volume = data;
163 }
164 }
165