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 B.4.6. Data Segment Fault

 A data segment fault occurs when the segment for the requested data is not in the hardware segment table. The steps leading up to a data segment fault and how the fault is resolved are as follows:

  1. The PSL is unable to locate a segment in the hardware segment table for converting the EA to a VA.

  2. The PSL sets the appropriate state in the PSL_DSISR_An Register (PSL_DSISR_An[DS]) and sends an interrupt to the associated operating system using LISN0.

  3. The operating system updates the hardware segment table with the requested segment, issues a sync instruction, and then writes the PSL_TFC_An[R] bit to a '1' to indicate that the PSL should restart the corresponding operation.

  4. The PSL restarts the operation and translates the EA-to-RA. The PSL should find the mapping for the hardware segment table.

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