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Intel 8254x: Difference between revisions
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Line 27:
There is also a BAR that will contain an I/O base address, this can be detected by looking at each BAR and testing bit 1.
When using MMIO, reading/writing to/from registers is very straight-forward.
<source lang="c">
*(uint32_t *)(ioaddr + reg) = val; // writes "val" to an MMIO address
val = *(uint32_t *)(ioaddr + reg); // reads "val" from an MMIO address
</source>
Line 39:
<source lang="c">
out32(ioaddr + 0x00, reg); // set the IOADDR window
out32(ioaddr + 0x04, val); // write the value to the IOADDR window which will end up in the register in IOADDR
in32(ioaddr + 0x04); // read back the value
</source>
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