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17 lines
608 B
Markdown
17 lines
608 B
Markdown
## Known differences between SimH, 11/70, and w11a
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### SimH: MMU traps not suppressed when MMU register accessed
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The 11/70 does not execute an MMU trap and doesn't set A or W bits in `PDR`
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when an MMU register is accessed, thus `MMR0` to `MMR3` and any of the
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`PDR` and `PAR` registers.
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SimH doesn't support this behavior.
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xxdp program `ekbee1` tests 061 and 063 verify this behavior and are skipped
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(see [patch](../tools/xxdp/ekbee1_patch_1170.scmd)).
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w11 also doesn't support this behavior, this is documented as
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[w11 known difference](w11a_diff_70_mmu_trap_suppression.md).
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Tested with SimH V3.12-3.
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