Blame aica/Dreamcast_sound.txt
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SOUND ON THE SEGA DREAMCAST
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The Sega Dreamcast includes a ARM7 processor that seperately handles sound
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playback. The ARM7 processor has its own address space which is only partially
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accessible to the main SH4 processor.
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The ALSA driver loads data to the ARM7 address space using DMA (which will
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run at a good speed). The old OSS driver did not use DMA and so showed
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very poor performance at high bit rates.
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The driver also loads some simple firmware (seperately licenced under a
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modified BSD licence) which controls the ARM7 processor. Without the
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firmware the driver would merely fill the ARM7's address space and would
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not playback any sound.
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The firmware, by default, should be loaded to /lib/firmware/ and should
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be named aica_firmware.bin.
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