getchar() / putchar() (Part 3)

• The 1-character buffer gives us some time to read/write

  • but not a lot

• Extend the 1-character buffers to 32 characters buffers

  • now we can go away for a long time and not miss incoming characters
  • we can write out lots of characters and not wait for them all to go

• Each buffer now becomes a queue

  • standard circular queue
    • 33 character vector (why 33?)
    • head, tail pointers
  • initialize on startup

• getchar()

  • interrupt routine writes characters to buffer, getchar() reads

• putchar()

  • putchar() writes characters to buffer, getchar() reads

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