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1.1 root 1: /*
2: * QEMU PC speaker emulation
3: *
4: * Copyright (c) 2006 Joachim Henke
5: *
6: * Permission is hereby granted, free of charge, to any person obtaining a copy
7: * of this software and associated documentation files (the "Software"), to deal
8: * in the Software without restriction, including without limitation the rights
9: * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10: * copies of the Software, and to permit persons to whom the Software is
11: * furnished to do so, subject to the following conditions:
12: *
13: * The above copyright notice and this permission notice shall be included in
14: * all copies or substantial portions of the Software.
15: *
16: * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17: * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19: * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20: * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21: * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22: * THE SOFTWARE.
23: */
24:
25: #include "vl.h"
26:
27: #define PCSPK_BUF_LEN 1792
28: #define PCSPK_SAMPLE_RATE 32000
29: #define PCSPK_MAX_FREQ (PCSPK_SAMPLE_RATE >> 1)
30: #define PCSPK_MIN_COUNT ((PIT_FREQ + PCSPK_MAX_FREQ - 1) / PCSPK_MAX_FREQ)
31:
32: typedef struct {
33: uint8_t sample_buf[PCSPK_BUF_LEN];
34: QEMUSoundCard card;
35: SWVoiceOut *voice;
36: PITState *pit;
37: unsigned int pit_count;
38: unsigned int samples;
39: unsigned int play_pos;
40: int data_on;
41: int dummy_refresh_clock;
42: } PCSpkState;
43:
44: static const char *s_spk = "pcspk";
45: static PCSpkState pcspk_state;
46:
47: static inline void generate_samples(PCSpkState *s)
48: {
49: unsigned int i;
50:
51: if (s->pit_count) {
52: const uint32_t m = PCSPK_SAMPLE_RATE * s->pit_count;
53: const uint32_t n = ((uint64_t)PIT_FREQ << 32) / m;
54:
55: /* multiple of wavelength for gapless looping */
56: s->samples = (PCSPK_BUF_LEN * PIT_FREQ / m * m / (PIT_FREQ >> 1) + 1) >> 1;
57: for (i = 0; i < s->samples; ++i)
58: s->sample_buf[i] = (64 & (n * i >> 25)) - 32;
59: } else {
60: s->samples = PCSPK_BUF_LEN;
61: for (i = 0; i < PCSPK_BUF_LEN; ++i)
62: s->sample_buf[i] = 128; /* silence */
63: }
64: }
65:
66: static void pcspk_callback(void *opaque, int free)
67: {
68: PCSpkState *s = opaque;
69: unsigned int n;
70:
71: if (pit_get_mode(s->pit, 2) != 3)
72: return;
73:
74: n = pit_get_initial_count(s->pit, 2);
75: /* avoid frequencies that are not reproducible with sample rate */
76: if (n < PCSPK_MIN_COUNT)
77: n = 0;
78:
79: if (s->pit_count != n) {
80: s->pit_count = n;
81: s->play_pos = 0;
82: generate_samples(s);
83: }
84:
85: while (free > 0) {
86: n = audio_MIN(s->samples - s->play_pos, (unsigned int)free);
87: n = AUD_write(s->voice, &s->sample_buf[s->play_pos], n);
88: if (!n)
89: break;
90: s->play_pos = (s->play_pos + n) % s->samples;
91: free -= n;
92: }
93: }
94:
95: int pcspk_audio_init(AudioState *audio)
96: {
97: PCSpkState *s = &pcspk_state;
1.1.1.2 ! root 98: audsettings_t as = {PCSPK_SAMPLE_RATE, 1, AUD_FMT_U8, 0};
1.1 root 99:
100: if (!audio) {
101: AUD_log(s_spk, "No audio state\n");
102: return -1;
103: }
104: AUD_register_card(audio, s_spk, &s->card);
105:
1.1.1.2 ! root 106: s->voice = AUD_open_out(&s->card, s->voice, s_spk, s, pcspk_callback, &as);
1.1 root 107: if (!s->voice) {
108: AUD_log(s_spk, "Could not open voice\n");
109: return -1;
110: }
111:
112: return 0;
113: }
114:
115: static uint32_t pcspk_ioport_read(void *opaque, uint32_t addr)
116: {
117: PCSpkState *s = opaque;
118: int out;
119:
120: s->dummy_refresh_clock ^= (1 << 4);
121: out = pit_get_out(s->pit, 2, qemu_get_clock(vm_clock)) << 5;
122:
123: return pit_get_gate(s->pit, 2) | (s->data_on << 1) | s->dummy_refresh_clock | out;
124: }
125:
126: static void pcspk_ioport_write(void *opaque, uint32_t addr, uint32_t val)
127: {
128: PCSpkState *s = opaque;
129: const int gate = val & 1;
130:
131: s->data_on = (val >> 1) & 1;
132: pit_set_gate(s->pit, 2, gate);
133: if (s->voice) {
134: if (gate) /* restart */
135: s->play_pos = 0;
136: AUD_set_active_out(s->voice, gate & s->data_on);
137: }
138: }
139:
140: void pcspk_init(PITState *pit)
141: {
142: PCSpkState *s = &pcspk_state;
143:
144: s->pit = pit;
145: register_ioport_read(0x61, 1, 1, pcspk_ioport_read, s);
146: register_ioport_write(0x61, 1, 1, pcspk_ioport_write, s);
147: }
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