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4fdb179dfc
- pdp11_sequencer.vhd: CPUERR cleared by CRESET - mminki.mac: added, procedure to initialize MMU, kernel I space only - test_w11a_cpuerr.tcl: added, test cpuerr register - added more README's - editorial changes
19 lines
626 B
Markdown
19 lines
626 B
Markdown
# ECO-029: `CPUERR` cleared by cpu reset (2016-12-27)
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### Scope
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- Was in w11a from the very beginning
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- Affects: all w11a systems
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### Symptom summary
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- the `cpuerr` register is not cleared by a `$cpu cp -creset` command
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- the `cpuerr` status can affect cpu behaviour, e.g. yellow stack traps are
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only taken when the corresponding `cpuerr` flag is not set
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- this makes tbench test execution on FPGA potentially depending on pre-history
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### Fixes
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Changed `pdp11_sequencer.vhd` to clear `cpuerr` with both general reset and
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with cpu reset.
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### Side effects
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None because this affects a very early phase of system startup.
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