148 lines
4.2 KiB
C
148 lines
4.2 KiB
C
/*
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* QEMU PC speaker emulation
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*
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* Copyright (c) 2006 Joachim Henke
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "hw.h"
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#include "pc.h"
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#include "isa.h"
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#include "audio/audio.h"
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#include "qemu-timer.h"
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#define PCSPK_BUF_LEN 1792
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#define PCSPK_SAMPLE_RATE 32000
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#define PCSPK_MAX_FREQ (PCSPK_SAMPLE_RATE >> 1)
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#define PCSPK_MIN_COUNT ((PIT_FREQ + PCSPK_MAX_FREQ - 1) / PCSPK_MAX_FREQ)
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typedef struct {
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uint8_t sample_buf[PCSPK_BUF_LEN];
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QEMUSoundCard card;
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SWVoiceOut *voice;
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PITState *pit;
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unsigned int pit_count;
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unsigned int samples;
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unsigned int play_pos;
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int data_on;
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int dummy_refresh_clock;
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} PCSpkState;
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static const char *s_spk = "pcspk";
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static PCSpkState pcspk_state;
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static inline void generate_samples(PCSpkState *s)
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{
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unsigned int i;
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if (s->pit_count) {
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const uint32_t m = PCSPK_SAMPLE_RATE * s->pit_count;
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const uint32_t n = ((uint64_t)PIT_FREQ << 32) / m;
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/* multiple of wavelength for gapless looping */
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s->samples = (PCSPK_BUF_LEN * PIT_FREQ / m * m / (PIT_FREQ >> 1) + 1) >> 1;
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for (i = 0; i < s->samples; ++i)
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s->sample_buf[i] = (64 & (n * i >> 25)) - 32;
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} else {
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s->samples = PCSPK_BUF_LEN;
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for (i = 0; i < PCSPK_BUF_LEN; ++i)
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s->sample_buf[i] = 128; /* silence */
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}
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}
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static void pcspk_callback(void *opaque, int free)
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{
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PCSpkState *s = opaque;
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unsigned int n;
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if (pit_get_mode(s->pit, 2) != 3)
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return;
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n = pit_get_initial_count(s->pit, 2);
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/* avoid frequencies that are not reproducible with sample rate */
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if (n < PCSPK_MIN_COUNT)
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n = 0;
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if (s->pit_count != n) {
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s->pit_count = n;
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s->play_pos = 0;
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generate_samples(s);
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}
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while (free > 0) {
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n = audio_MIN(s->samples - s->play_pos, (unsigned int)free);
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n = AUD_write(s->voice, &s->sample_buf[s->play_pos], n);
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if (!n)
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break;
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s->play_pos = (s->play_pos + n) % s->samples;
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free -= n;
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}
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}
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int pcspk_audio_init(qemu_irq *pic)
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{
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PCSpkState *s = &pcspk_state;
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struct audsettings as = {PCSPK_SAMPLE_RATE, 1, AUD_FMT_U8, 0};
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AUD_register_card(s_spk, &s->card);
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s->voice = AUD_open_out(&s->card, s->voice, s_spk, s, pcspk_callback, &as);
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if (!s->voice) {
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AUD_log(s_spk, "Could not open voice\n");
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return -1;
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}
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return 0;
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}
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static uint32_t pcspk_ioport_read(void *opaque, uint32_t addr)
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{
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PCSpkState *s = opaque;
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int out;
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s->dummy_refresh_clock ^= (1 << 4);
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out = pit_get_out(s->pit, 2, qemu_get_clock(vm_clock)) << 5;
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return pit_get_gate(s->pit, 2) | (s->data_on << 1) | s->dummy_refresh_clock | out;
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}
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static void pcspk_ioport_write(void *opaque, uint32_t addr, uint32_t val)
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{
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PCSpkState *s = opaque;
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const int gate = val & 1;
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s->data_on = (val >> 1) & 1;
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pit_set_gate(s->pit, 2, gate);
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if (s->voice) {
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if (gate) /* restart */
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s->play_pos = 0;
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AUD_set_active_out(s->voice, gate & s->data_on);
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}
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}
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void pcspk_init(PITState *pit)
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{
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PCSpkState *s = &pcspk_state;
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s->pit = pit;
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register_ioport_read(0x61, 1, 1, pcspk_ioport_read, s);
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register_ioport_write(0x61, 1, 1, pcspk_ioport_write, s);
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}
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