Input Output (I/O)

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Input Output (I/O)#

The way a machine receives input and gives output.

Polling#

Constantly looping an instruction checking if there is an input

Interrupt#

Input signals the computer to stop what its doing and read the input.

  1. Incoming interrupt suspends instruction stream

  2. Look up the vector (function address) of a handler in an interrupt vector table stored within the CPU

  3. Perform a jal to handler

    • Save PC in Machine Exception Program Counter (MEPC) register

  4. Handler run on current stack and returns on finish

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