On 23.8.2012 17:41, Ján Veselý wrote: > My understanding was that programmed I/O meant using special > instructions for i/o operations (unlike mmio or dma).
No no, programmed here means that the I/O is done by the CPU as a result of executing an I/O read/write instruction (no matter whether via a port or mmio, the device doesn't care either as both are the same). The opposite of programmed in this context is DMA, which is done autonomously by e.g. the DMA controller. > more so that in other places (like Linux kernel) pio term is used for > x86 port access. Well, the semantics of symbols is usually not very portable across different OS kernels :-) Jakub _______________________________________________ HelenOS-devel mailing list [email protected] http://lists.modry.cz/cgi-bin/listinfo/helenos-devel
