118 lines
2.9 KiB
C
118 lines
2.9 KiB
C
/*
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* 86Box A hypervisor and IBM PC system emulator that specializes in
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* running old operating systems and software designed for IBM
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* PC systems and compatibles from 1981 through fairly recent
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* system designs based on the PCI bus.
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*
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* This file is part of the 86Box distribution.
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*
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* Emulation of the PC speaker.
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*
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*
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*
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* Authors: Sarah Walker, <https://pcem-emulator.co.uk/>
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* Miran Grca, <mgrca8@gmail.com>
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*
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* Copyright 2008-2019 Sarah Walker.
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* Copyright 2016-2019 Miran Grca.
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*/
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <wchar.h>
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#include <86box/86box.h>
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#include <86box/timer.h>
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#include <86box/pit.h>
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#include <86box/snd_speaker.h>
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#include <86box/sound.h>
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#include <86box/plat_unused.h>
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int speaker_mute = 0;
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int speaker_gated = 0;
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int speaker_enable = 0;
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int was_speaker_enable = 0;
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int gated;
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int speakval;
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int speakon;
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static int32_t speaker_buffer[SOUNDBUFLEN];
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static int speaker_pos = 0;
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static uint8_t speaker_mode = 0;
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static double speaker_count = 65535.0;
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void
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speaker_set_count(uint8_t new_m, int new_count)
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{
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speaker_mode = new_m;
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speaker_count = (double) new_count;
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}
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void
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speaker_update(void)
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{
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int32_t val;
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double amplitude;
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amplitude = ((speaker_count / 64.0) * 10240.0) - 5120.0;
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if (amplitude > 5120.0)
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amplitude = 5120.0;
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if (speaker_pos < sound_pos_global) {
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for (; speaker_pos < sound_pos_global; speaker_pos++) {
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if (speaker_gated && was_speaker_enable) {
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if ((speaker_mode == 0) || (speaker_mode == 4))
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val = (int32_t) amplitude;
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else if (speaker_count < 64.0)
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val = 0xa00;
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else
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val = speakon ? 0x1400 : 0;
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} else {
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if (speaker_mode == 1)
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val = was_speaker_enable ? (int32_t) amplitude : 0;
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else
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val = was_speaker_enable ? 0x1400 : 0;
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}
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if (!speaker_enable)
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was_speaker_enable = 0;
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speaker_buffer[speaker_pos] = val;
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}
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}
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}
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void
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speaker_get_buffer(int32_t *buffer, int len, UNUSED(void *priv))
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{
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double val_l, val_r;
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speaker_update();
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if (!speaker_mute) {
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for (int c = 0; c < len * 2; c += 2) {
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val_l = val_r = (double) speaker_buffer[c >> 1];
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/* Apply PC speaker volume and filters */
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if (filter_pc_speaker != NULL) {
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filter_pc_speaker(0, &val_l, filter_pc_speaker_p);
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filter_pc_speaker(1, &val_r, filter_pc_speaker_p);
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}
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buffer[c] += (int32_t) val_l;
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buffer[c + 1] += (int32_t) val_r;
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}
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}
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speaker_pos = 0;
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}
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void
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speaker_init(void)
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{
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memset(speaker_buffer, 0, sizeof(speaker_buffer));
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sound_add_handler(speaker_get_buffer, NULL);
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speaker_mute = 0;
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}
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