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Handle double-RED abort conditions by stopping the CPU and reporting a PANIC

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This commit is contained in:
Jeff Parsons 2016-12-01 20:07:33 -08:00 • committed by Jeff Parsons
commit 02b1b8a34a
12 changed files with 180 additions and 174 deletions
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74
modules/pdp11/lib/cpustate.js
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@ -1368,47 +1368,50 @@ CPUStatePDP11.prototype.trap = function(vector, flag, reason)
reason = PDP11.REASON.RED; // double-fault (nested trap) forces a RED condition
}
var fRed = false;
if (reason == PDP11.REASON.RED) {
vector = 4;
if (this.opFlags & PDP11.OPFLAG.TRAP_RED) {
reason = PDP11.REASON.PANIC;
}
this.opFlags |= PDP11.OPFLAG.TRAP_RED;
/*
* The next two lines used to be deferred until after the setPSW() below, but
* I'm not seeing any dependencies on these registers, so I'm consolidating the code.
*/
this.regErr |= PDP11.CPUERR.RED;
this.regsGen[6] = 4;
fRed = true;
this.regsGen[6] = vector = 4;
}
/*
* NOTE: Pre-setting the auto-dec values for MMR1 to 0xF6F6 is a work-around for an "EKBEE1"
* diagnostic (PC 056710), which tests what happens when a misaligned read triggers a BUS trap,
* and that trap then triggers an MMU trap during the first pushWord() below.
*
* One would think it would be fine to zero those bits by setting opLast to vector alone,
* and then letting each of the pushWord() calls below shift their own 0xF6 auto-dec value into
* opLast. When the first pushWord() triggers an MMU trap, we obviously won't get to the second
* pushWord(), yet the diagnostic expects TWO auto-decs to be recorded. I'm puzzled why the
* hardware apparently indicates TWO auto-decs, if SP wasn't actually decremented twice, but who
* am I to judge.
*/
this.opLast = vector | 0xf6f60000;
if (reason != PDP11.REASON.PANIC) {
/*
* NOTE: Pre-setting the auto-dec values for MMR1 to 0xF6F6 is a work-around for an "EKBEE1"
* diagnostic (PC 056710), which tests what happens when a misaligned read triggers a BUS trap,
* and that trap then triggers an MMU trap during the first pushWord() below.
*
* One would think it would be fine to zero those bits by setting opLast to vector alone,
* and then letting each of the pushWord() calls below shift their own 0xF6 auto-dec value into
* opLast. When the first pushWord() triggers an MMU trap, we obviously won't get to the second
* pushWord(), yet the diagnostic expects TWO auto-decs to be recorded. I'm puzzled why the
* hardware apparently indicates TWO auto-decs, if SP wasn't actually decremented twice, but who
* am I to judge.
*/
this.opLast = vector | 0xf6f60000;
/*
* Read from kernel D space
*/
this.mmuMode = 0;
var newPC = this.readWord(vector | this.addrDSpace);
var newPSW = this.readWord(((vector + 2) & 0xffff) | this.addrDSpace);
/*
* Read from kernel D space
*/
this.mmuMode = 0;
var newPC = this.readWord(vector | this.addrDSpace);
var newPSW = this.readWord(((vector + 2) & 0xffff) | this.addrDSpace);
/*
* Set new PSW with previous mode
*/
this.setPSW((newPSW & ~PDP11.PSW.PMODE) | ((this.trapPSW >> 2) & PDP11.PSW.PMODE));
/*
* Set new PSW with previous mode
*/
this.setPSW((newPSW & ~PDP11.PSW.PMODE) | ((this.trapPSW >> 2) & PDP11.PSW.PMODE));
this.pushWord(this.trapPSW, fRed);
this.pushWord(this.regsGen[7], fRed);
this.setPC(newPC);
this.pushWord(this.trapPSW);
this.pushWord(this.regsGen[7]);
this.setPC(newPC);
}
/*
* TODO: Determine the appropriate number of cycles for traps; all I've done for now is move the
@ -1459,6 +1462,9 @@ CPUStatePDP11.prototype.trap = function(vector, flag, reason)
this.trapVector = vector;
this.trapReason = reason;
if (reason == PDP11.REASON.PANIC) {
this.stopCPU();
}
if (reason >= PDP11.REASON.RED) throw vector;
};
@ -1790,18 +1796,17 @@ CPUStatePDP11.prototype.popWord = function()
};
/**
* pushWord(data, fRed)
* pushWord(data)
*
* @this {CPUStatePDP11}
* @param {number} data
* @param {boolean} [fRed]
*/
CPUStatePDP11.prototype.pushWord = function(data, fRed)
CPUStatePDP11.prototype.pushWord = function(data)
{
var addrVirtual = (this.regsGen[6] - 2) & 0xffff;
this.regsGen[6] = addrVirtual; // BSD needs SP updated before any fault :-(
this.opLast = (this.opLast & 0xffff) | ((this.opLast & ~0xffff) << 8) | (0x00f6 << 16);
if (!fRed) this.checkStackLimit(PDP11.ACCESS.WRITE_WORD, -2, addrVirtual);
if (!(this.opFlags & PDP11.OPFLAG.TRAP_RED)) this.checkStackLimit(PDP11.ACCESS.WRITE_WORD, -2, addrVirtual);
this.writeWord(addrVirtual, data);
};
@ -2623,6 +2628,7 @@ CPUStatePDP11.prototype.stepCPU = function(nMinCycles)
} else {
this.assert(!this.irqNext && !this.regPIR);
}
/*
* Snapshot the TF bit in opFlags, while clearing all other opFlags (except those in PRESERVE);
* we'll check the TRAP_TF bit in opFlags when we come back around for another opcode.