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Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
222 lines
7.8 KiB
Text
222 lines
7.8 KiB
Text
Support for the OPTi 82C931 chip
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--------------------------------
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Note: parts of this README file apply also to other
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cards that use the mad16 driver.
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Some items in this README file are based on features
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added to the sound driver after Linux-2.1.91 was out.
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By the time of writing this I do not know which official
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kernel release will include these features.
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Please do not report inconsistencies on older Linux
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kernels.
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The OPTi 82C931 is supported in its non-PnP mode.
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Usually you do not need to set jumpers, etc. The sound driver
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will check the card status and if it is required it will
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force the card into a mode in which it can be programmed.
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If you have another OS installed on your computer it is recommended
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that Linux and the other OS use the same resources.
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Also, it is recommended that resources specified in /etc/modprobe.conf
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and resources specified in /etc/isapnp.conf agree.
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Compiling the sound driver
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--------------------------
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I highly recommend that you build a modularized sound driver.
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This document does not cover a sound-driver which is built in
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the kernel.
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Sound card support should be enabled as a module (chose m).
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Answer 'm' for these items:
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Generic OPL2/OPL3 FM synthesizer support (CONFIG_SOUND_ADLIB)
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Microsoft Sound System support (CONFIG_SOUND_MSS)
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Support for OPTi MAD16 and/or Mozart based cards (CONFIG_SOUND_MAD16)
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FM synthesizer (YM3812/OPL-3) support (CONFIG_SOUND_YM3812)
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The configuration menu may ask for addresses, IRQ lines or DMA
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channels. If the card is used as a module the module loading
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options will override these values.
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For the OPTi 931 you can answer 'n' to:
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Support MIDI in older MAD16 based cards (requires SB) (CONFIG_SOUND_MAD16_OLDCARD)
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If you do need MIDI support in a Mozart or C928 based card you
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need to answer 'm' to the above question. In that case you will
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also need to answer 'm' to:
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'100% Sound Blaster compatibles (SB16/32/64, ESS, Jazz16) support' (CONFIG_SOUND_SB)
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Go on and compile your kernel and modules. Install the modules. Run depmod -a.
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Using isapnptools
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-----------------
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In most systems with a PnP BIOS you do not need to use isapnp. The
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initialization provided by the BIOS is sufficient for the driver
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to pick up the card and continue initialization.
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If that fails, or if you have other PnP cards, you need to use isapnp
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to initialize the card.
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This was tested with isapnptools-1.11 but I recommend that you use
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isapnptools-1.13 (or newer). Run pnpdump to dump the information
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about your PnP cards. Then edit the resulting file and select
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the options of your choice. This file is normally installed as
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/etc/isapnp.conf.
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The driver has one limitation with respect to I/O port resources:
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IO3 base must be 0x0E0C. Although isapnp allows other ports, this
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address is hard-coded into the driver.
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Using kmod and autoloading the sound driver
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-------------------------------------------
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Comment: as of linux-2.1.90 kmod is replacing kerneld.
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The config file '/etc/modprobe.conf' is used as before.
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This is the sound part of my /etc/modprobe.conf file.
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Following that I will explain each line.
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alias mixer0 mad16
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alias audio0 mad16
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alias midi0 mad16
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alias synth0 opl3
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options sb mad16=1
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options mad16 irq=10 dma=0 dma16=1 io=0x530 joystick=1 cdtype=0
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options opl3 io=0x388
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install mad16 /sbin/modprobe -i mad16 && /sbin/ad1848_mixer_reroute 14 8 15 3 16 6
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If you have an MPU daughtercard or onboard MPU you will want to add to the
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"options mad16" line - eg
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options mad16 irq=5 dma=0 dma16=3 io=0x530 mpu_io=0x330 mpu_irq=9
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To set the I/O and IRQ of the MPU.
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Explain:
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alias mixer0 mad16
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alias audio0 mad16
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alias midi0 mad16
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alias synth0 opl3
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When any sound device is opened the kernel requests auto-loading
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of char-major-14. There is a built-in alias that translates this
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request to loading the main sound module.
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The sound module in its turn will request loading of a sub-driver
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for mixer, audio, midi or synthesizer device. The first 3 are
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supported by the mad16 driver. The synth device is supported
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by the opl3 driver.
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There is currently no way to autoload the sound device driver
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if more than one card is installed.
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options sb mad16=1
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This is left for historical reasons. If you enable the
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config option 'Support MIDI in older MAD16 based cards (requires SB)'
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or if you use an older mad16 driver it will force loading of the
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SoundBlaster driver. This option tells the SB driver not to look
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for a SB card but to wait for the mad16 driver.
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options mad16 irq=10 dma=0 dma16=1 io=0x530 joystick=1 cdtype=0
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options opl3 io=0x388
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post-install mad16 /sbin/ad1848_mixer_reroute 14 8 15 3 16 6
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This sets resources and options for the mad16 and opl3 drivers.
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I use two DMA channels (only one is required) to enable full duplex.
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joystick=1 enables the joystick port. cdtype=0 disables the cd port.
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You can also set mpu_io and mpu_irq in the mad16 options for the
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uart401 driver.
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This tells modprobe to run /sbin/ad1848_mixer_reroute after
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mad16 is successfully loaded and initialized. The source
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for ad1848_mixer_reroute is appended to the end of this readme
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file. It is impossible for the sound driver to know the actual
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connections to the mixer. The 3 inputs intended for cd, synth
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and line-in are mapped to the generic inputs line1, line2 and
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line3. This program reroutes these mixer channels to their
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right names (note the right mapping depends on the actual sound
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card that you use).
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The numeric parameters mean:
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14=line1 8=cd - reroute line1 to the CD input.
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15=line2 3=synth - reroute line2 to the synthesizer input.
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16=line3 6=line - reroute line3 to the line input.
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For reference on other input names look at the file
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/usr/include/linux/soundcard.h.
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Using a joystick
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-----------------
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You must enable a joystick in the mad16 options. (also
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in /etc/isapnp.conf if you use it).
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Tested with regular analog joysticks.
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A CDROM drive connected to the sound card
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-----------------------------------------
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The 82C931 chip has support only for secondary ATAPI cdrom.
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(cdtype=8). Loading the mad16 driver resets the C931 chip
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and if a cdrom was already mounted it may cause a complete
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system hang. Do not use the sound card if you have an alternative.
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If you do use the sound card it is important that you load
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the mad16 driver (use "modprobe mad16" to prevent auto-unloading)
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before the cdrom is accessed the first time.
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Using the sound driver built-in to the kernel may help here, but...
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Most new systems have a PnP BIOS and also two IDE controllers.
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The IDE controller on the sound card may be needed only on older
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systems (which have only one IDE controller) but these systems
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also do not have a PnP BIOS - requiring isapnptools and a modularized
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driver.
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Known problems
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--------------
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1. See the section on "A CDROM drive connected to the sound card".
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2. On my system the codec cannot capture companded sound samples.
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(eg., recording from /dev/audio). When any companded capture is
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requested I get stereo-16 bit samples instead. Playback of
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companded samples works well. Apparently this problem is not common
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to all C931 based cards. I do not know how to identify cards that
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have this problem.
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Source for ad1848_mixer_reroute.c
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---------------------------------
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#include <stdio.h>
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#include <fcntl.h>
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#include <linux/soundcard.h>
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static char *mixer_names[SOUND_MIXER_NRDEVICES] =
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SOUND_DEVICE_LABELS;
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int
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main(int argc, char **argv) {
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int val, from, to;
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int i, fd;
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fd = open("/dev/mixer", O_RDWR);
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if(fd < 0) {
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perror("/dev/mixer");
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return 1;
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}
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for(i = 2; i < argc; i += 2) {
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from = atoi(argv[i-1]);
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to = atoi(argv[i]);
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if(to == SOUND_MIXER_NONE)
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fprintf(stderr, "%s: turning off mixer %s\n",
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argv[0], mixer_names[to]);
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else
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fprintf(stderr, "%s: rerouting mixer %s to %s\n",
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argv[0], mixer_names[from], mixer_names[to]);
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val = from << 8 | to;
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if(ioctl(fd, SOUND_MIXER_PRIVATE2, &val)) {
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perror("AD1848 mixer reroute");
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return 1;
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}
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}
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return 0;
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}
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