mirror of
https://github.com/Oibaf66/frodo-wii.git
synced 2024-11-22 19:39:24 +01:00
126 lines
2.6 KiB
OpenEdge ABL
126 lines
2.6 KiB
OpenEdge ABL
/*
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* SID_linux.i - 6581 emulation, Linux specific stuff
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*
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* Frodo (C) 1994-1997,2002 Christian Bauer
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* Linux sound stuff by Bernd Schmidt
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*/
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <linux/soundcard.h>
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#include "VIC.h"
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/*
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* Initialization
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*/
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void DigitalRenderer::init_sound(void)
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{
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int tmp;
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unsigned long format;
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ready = false;
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devfd = open("/dev/dsp", O_WRONLY);
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if (devfd < 0)
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return;
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ioctl(devfd, SNDCTL_DSP_GETFMTS, &format);
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if (!(format & AFMT_S16_LE))
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return;
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format = AFMT_S16_LE;
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ioctl(devfd, SNDCTL_DSP_SETFMT, &format);
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/*
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* Buffer size: 2^9 == 512 bytes. Note that too large buffers will not work
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* very well: The speed of the C64 is slowed down to an average speed of
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* 100% by the blocking write() call in EmulateLine(). If you use a buffer
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* of, say 4096 bytes, that will happen only about every 4 frames, which
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* means that the emulation runs much faster in some frames, and much
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* slower in others.
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* On really fast machines, it might make sense to use an even smaller
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* buffer size.
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*/
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tmp = 0x00100009;
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ioctl(devfd, SNDCTL_DSP_SETFRAGMENT, &tmp);
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tmp = 0;
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ioctl(devfd, SNDCTL_DSP_STEREO, &tmp);
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tmp = 44100;
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ioctl(devfd, SNDCTL_DSP_SPEED, &tmp);
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ioctl(devfd, SOUND_PCM_READ_RATE, &tmp);
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if (tmp < 43000 || tmp > 45000)
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return;
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ioctl(devfd, SNDCTL_DSP_GETBLKSIZE, &sndbufsize);
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sound_buffer = new int16[sndbufsize];
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ready = true;
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}
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/*
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* Destructor
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*/
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DigitalRenderer::~DigitalRenderer()
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{
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if (devfd >= 0)
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close(devfd);
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}
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/*
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* Pause sound output
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*/
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void DigitalRenderer::Pause(void)
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{
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}
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/*
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* Resume sound output
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*/
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void DigitalRenderer::Resume(void)
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{
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}
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/*
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* Fill buffer, sample volume (for sampled voice)
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*/
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void DigitalRenderer::EmulateLine(void)
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{
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static int divisor = 0;
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static int to_output = 0;
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static int buffer_pos = 0;
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if (!ready)
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return;
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sample_buf[sample_in_ptr] = volume;
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sample_in_ptr = (sample_in_ptr + 1) % SAMPLE_BUF_SIZE;
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/*
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* Now see how many samples have to be added for this line
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*/
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divisor += SAMPLE_FREQ;
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while (divisor >= 0)
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divisor -= TOTAL_RASTERS*SCREEN_FREQ, to_output++;
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/*
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* Calculate the sound data only when we have enough to fill
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* the buffer entirely.
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*/
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if ((buffer_pos + to_output) >= sndbufsize) {
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int datalen = sndbufsize - buffer_pos;
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to_output -= datalen;
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calc_buffer(sound_buffer + buffer_pos, datalen*2);
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write(devfd, sound_buffer, sndbufsize*2);
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buffer_pos = 0;
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}
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}
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