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Converted previous notes to a TODO

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This commit is contained in:
Jeff Parsons 2016-11-19 17:13:04 -08:00 • committed by Jeff Parsons
commit b98a31c7b8
1 changed files with 6 additions and 3 deletions
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9
modules/pdp11/lib/cpustate.js
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@ -1777,9 +1777,12 @@ CPUStatePDP11.prototype.pushWord = function(data, fRed)
* by SP in either mode 4 (auto-decrement) or 5 (auto-decrement deferred). The instruction
* is allowed to complete before the trap is issued. NOTE: This information comes
* directly from the PDP-11/20 Handbook (1971), but the 11/20 diagnostics apparently only
* test mode 4, not mode 5, because when I removed stack limit checks for mode 5 on the
* 11/70, none of the 11/20 tests complained. So, I still need some independent confirmation
* as to whether ANY models check for stack overflow on mode 5 (auto-decrement deferred).
* test mode 4, not mode 5, because when I later removed stack limit checks for mode 5 on
* the 11/70, none of the 11/20 tests complained.
*
* TODO: Find some independent confirmation as to whether ANY PDP-11 models check for
* stack overflow on mode 5 (auto-decrement deferred); if they do, then further tweaks to
* checkStackLimit functions may be required.
*
* On the PDP-11/70, the stack limit register (177774) allows a variable boundary for the
* kernel stack.