General IO port
[IO File]

General IO File port connectivity

The general IO File port is a little bit more ellaborated than a simple read/write port. It can read bytes from IO registers to output and write bytes from input to IO registers. Also, it can do some bit processing: load bits (from T flag in SREG to output), store bits (from input to T bit in SREG), set IO bits, clear IO bits.
An opcode has to be provided to specify one of the actions that this port is capable of.

The following opcodes are implemented for the IO File general port:

• read byte (needed by instructions IN, SBIC, SBIS)
• write byte (OUT)
• clear bit (CBI)
• set bit (SBI)
• load bit (BLD)
• store bit (BST)

Requests to this port

• pavr_s5_iof_rq
  Needed by instructions that manipulate IO File in stage s5: CBI, SBI, SBIC, SBIS, BSET, BCLR, IN, OUT, BLD, BST.
• pavr_s6_iof_rq
  Needed by instructions that manipulate IO File in stage s6: CBI, SBI, BSET, BCLR.
• pavr_s5_dacu_iof_rq
  Needed by loads and stores that are decoded by DACU as accessing IO File.
  
  

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