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24 lines
929 B
Markdown
24 lines
929 B
Markdown
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Writing a "bare metal" operating system for Raspberry Pi 4 (Part 10)
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====================================================================
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Using multiple CPU cores
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------------------------
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Instead of a background DMA transfer, I suggested that we might use a second CPU core to play the audio whilst our main core continues on. I also said it would be hard on the Raspberry Pi 4... and it is.
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This code isn't great yet, but it's enough to prove the concept in principle. Importantly, you'll need to modify your _config.txt_ file on your SD card to include the following lines:
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```c
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kernel_old=1
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disable_commandline_tags=1
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arm_64bit=1
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```
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For now, the points of interest in the code are:
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* The new _boot.S_ and related _boot.h_ loader
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* The new _multicore.c_ and _multicore.h_ files
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* A slimmed down _io.h_ and _kernel.c_ (DMA sound removed), with a new approach to `main()`
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* A revised _link.ld_
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I will write more soon!
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