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Made some progress with DEC's "TRAP TEST", but looks like it still needs some work

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This commit is contained in:
Jeff 2016-11-10 15:51:47 -08:00 • committed by Jeff Parsons
commit db63c30c1e
24 changed files with 1252 additions and 555 deletions
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140
modules/pdp11/lib/cpustate.js
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@ -825,7 +825,7 @@ CPUStatePDP11.prototype.dispatchInterrupt = function(vector, priority)
this.advancePC(2);
this.opFlags &= ~PDP11.OPFLAG.WAIT;
}
this.trap(vector, PDP11.REASON.INTERRUPT);
this.trap(vector, 0, PDP11.REASON.INTERRUPT);
return true;
}
return false;
@ -1083,6 +1083,13 @@ CPUStatePDP11.prototype.updateMulFlags = function(result)
/*
* NOTE: Technically, the MUL instruction doesn't need to worry about NO_FLAGS, because that instruction
* doesn't write to the bus, and therefore can't modify the PSW directly. But it doesn't hurt to be consistent.
*
* TODO: Conduct a review of all opcode handlers, because one possible alternative to all this NO_FLAGS nonsense
* would be to pass the appropriate flag update function to the writeDstByte()/writeDstWord() functions, and
* have them update the flags BEFORE the write occurs, thus allowing any subsequent write to the PSW to be honored.
*
* That already happens automatically with the updateDstByte()/updateDstWord() functions, since generally the
* specified modify function also updates the flags BEFORE the write occurs.
*/
if (!(this.opFlags & PDP11.OPFLAG.NO_FLAGS)) {
this.flagN = result >> 16;
@ -1139,7 +1146,7 @@ CPUStatePDP11.prototype.panic = function(reason)
};
/**
* trap(vector, reason)
* trap(vector, flag, reason)
*
* trap() handles all the trap/abort functions. It reads the trap vector from kernel
* D space, changes mode to reflect the new PSW and PC, and then pushes the old PSW and
@ -1147,9 +1154,10 @@ CPUStatePDP11.prototype.panic = function(reason)
*
* @this {CPUStatePDP11}
* @param {number} vector
* @param {number} flag
* @param {number} [reason] (for diagnostic purposes only)
*/
CPUStatePDP11.prototype.trap = function(vector, reason)
CPUStatePDP11.prototype.trap = function(vector, flag, reason)
{
if (DEBUG && this.dbg) {
if (this.messageEnabled(MessagesPDP11.TRAP)) {
@ -1194,8 +1202,15 @@ CPUStatePDP11.prototype.trap = function(vector, reason)
this.pushWord(this.regsGen[7]);
this.setPC(newPC);
this.opFlags &= ~PDP11.OPFLAG.TRAP_MASK; // lose interest in traps after an abort
this.trapPSW = -1; // reset flag that we have a trap within a trap
/*
* Since DEC's "TRAP TEST" triggers a RESERVED (instruction) trap with the stack deliberately
* set too low, and expects the stack overflow trap to be "sprung" immediately afterward, we only
* want to "lose interest" in TRAP flags that were set on entry.
*
* this.opFlags &= ~PDP11.OPFLAG.TRAP_MASK; // lose interest in traps after an abort
*/
this.opFlags &= ~flag;
this.trapPSW = -1; // reset flag that we have a trap within a trap
/*
* These next properties are purely an aid for the Debugger; see getTrapStatus()
@ -1435,7 +1450,7 @@ CPUStatePDP11.prototype.mapVirtualToPhysical = function(virtualAddress, accessFl
}
}
if (fTrap) { // don't trap until the end, because it throws an exception
this.trap(PDP11.TRAP.MMU, PDP11.REASON.MAPERROR);
this.trap(PDP11.TRAP.MMU, 0, PDP11.REASON.MAPERROR);
}
}
return physicalAddress;
@ -1494,18 +1509,35 @@ CPUStatePDP11.prototype.pushWord = function(data)
if (!(this.regMMR0 & 0xe000)) {
this.regMMR1 = (this.regMMR1 << 8) | 0xf6;
}
this.checkStackLimit(0, virtualAddress);
this.writeWord(virtualAddress, data);
};
if ((!this.mmuMode) && virtualAddress <= this.regSL && virtualAddress > 4) {
if (virtualAddress <= this.regSL - 32) {
this.regErr |= PDP11.CPUERR.RED;
this.regsGen[6] = 4;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.PUSHERROR);
} else {
this.regErr |= PDP11.CPUERR.YELLOW;
this.opFlags |= 4;
/**
* checkStackLimit(mode, addr)
*
* @this {CPUStatePDP11}
* @param {number} mode (ie, the addressing mode; 0 if push)
* @param {number} addr
*/
CPUStatePDP11.prototype.checkStackLimit = function(mode, addr)
{
if (!this.mmuMode && !(this.opFlags & PDP11.OPFLAG.TRAP_SP)) {
if (addr <= this.regSL && (mode || addr > 4) || mode && addr >= 0xfffe) {
if (this.model >= PDP11.MODEL_1145 && (addr <= this.regSL - 32 || mode == 1 && addr >= 0xfffe)) {
this.regErr |= PDP11.CPUERR.RED;
this.regsGen[6] = 4;
this.trap(PDP11.TRAP.BUS_ERROR, 0, PDP11.REASON.STACKMODE1);
} else {
/*
* On older machines (eg, the PDP-11/20), the instruction is always allowed to complete,
* so the trap must always be issued in this fashion.
*/
this.regErr |= PDP11.CPUERR.YELLOW;
this.opFlags |= PDP11.OPFLAG.TRAP_SP;
}
}
}
this.writeWord(virtualAddress, data);
};
/**
@ -1532,6 +1564,15 @@ CPUStatePDP11.prototype.pushWord = function(data)
* incremented and decremented so that the OS can reset and restart an instruction
* if a page fault occurs.
*
* Stack Overflow Traps
* --------------------
* On the PDP-11/20, stack overflow traps occur when an address below 400 is referenced
* by SP in either mode 4 (auto-decrement) or 5 (auto-decrement deferred). The instruction
* is allowed to complete before the trap is issued.
*
* On the PDP-11/70, the stack limit register (177774) allows a variable boundary for the
* kernel stack.
*
* @this {CPUStatePDP11}
* @param {number} mode
* @param {number} reg
@ -1544,8 +1585,8 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
var addrDSpace = (accessFlags & PDP11.ACCESS.VIRT)? 0 : this.addrDSpace;
/*
* Modes that need to auto-increment or auto-decrement will break, in order to perform the
* update; others will return an address immediately.
* Modes that need to auto-increment or auto-decrement will break, in order to perform
* the update; others will return an address immediately.
*/
switch (mode) {
/*
@ -1556,26 +1597,18 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
* "cause an 'illegal' instruction" condition", which presumably means a BUS_ERROR trap.
*/
case 0:
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.NOREGADDR);
this.trap(PDP11.TRAP.BUS_ERROR, 0, PDP11.REASON.NOREGADDR);
return 0;
/*
* Mode 1: (R)
*/
case 1:
if (reg === 6 && (!this.mmuMode) && (accessFlags & PDP11.ACCESS.WRITE) &&
(this.regsGen[6] <= this.regSL || this.regsGen[6] >= 0xfffe)) {
if (this.regsGen[6] <= this.regSL - 32 || this.regsGen[6] >= 0xfffe) {
this.regErr |= PDP11.CPUERR.RED;
this.regsGen[6] = 4;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.STACKMODE1);
} else {
this.regErr |= PDP11.CPUERR.YELLOW;
this.opFlags |= PDP11.OPFLAG.TRAP_SP;
}
if (reg == 6 && (accessFlags & PDP11.ACCESS.WRITE)) {
this.checkStackLimit(mode, this.regsGen[6]);
}
this.nStepCycles -= (2 + 1);
return (reg === 7? this.regsGen[reg] : (this.regsGen[reg] | addrDSpace));
return (reg == 7? this.regsGen[reg] : (this.regsGen[reg] | addrDSpace));
/*
* Mode 2: (R)+
@ -1583,7 +1616,7 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
case 2:
stepSize = 2;
virtualAddress = this.regsGen[reg];
if (reg !== 7) {
if (reg != 7) {
virtualAddress |= addrDSpace;
if (reg < 6 && (accessFlags & PDP11.ACCESS.BYTE)) {
stepSize = 1;
@ -1598,7 +1631,7 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
case 3:
stepSize = 2;
virtualAddress = this.regsGen[reg];
if (reg !== 7) virtualAddress |= addrDSpace;
if (reg != 7) virtualAddress |= addrDSpace;
virtualAddress = this.readWord(virtualAddress);
virtualAddress |= addrDSpace;
this.nStepCycles -= (5 + 2);
@ -1611,7 +1644,7 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
stepSize = -2;
if (reg < 6 && (accessFlags & PDP11.ACCESS.BYTE)) stepSize = -1;
virtualAddress = (this.regsGen[reg] + stepSize) & 0xffff;
if (reg !== 7) virtualAddress |= addrDSpace;
if (reg != 7) virtualAddress |= addrDSpace;
this.nStepCycles -= (3 + 1);
break;
@ -1621,7 +1654,7 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
case 5:
stepSize = -2;
virtualAddress = (this.regsGen[reg] - 2) & 0xffff;
if (reg !== 7) virtualAddress |= addrDSpace;
if (reg != 7) virtualAddress |= addrDSpace;
virtualAddress = this.readWord(virtualAddress) | addrDSpace;
this.nStepCycles -= (6 + 2);
break;
@ -1652,15 +1685,12 @@ CPUStatePDP11.prototype.getAddrByMode = function(mode, reg, accessFlags)
this.regMMR1 = (this.regMMR1 << 8) | ((stepSize << 3) & 0xf8) | reg;
}
if (reg == 6 && (!this.mmuMode) && (accessFlags & PDP11.ACCESS.WRITE) && stepSize <= 0 && (this.regsGen[6] <= this.regSL || this.regsGen[6] >= 0xfffe)) {
if (this.regsGen[6] <= this.regSL - 32) {
this.regErr |= PDP11.CPUERR.RED;
this.regsGen[6] = 4;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.STACKERROR);
} else {
this.regErr |= PDP11.CPUERR.YELLOW;
this.opFlags |= PDP11.OPFLAG.TRAP_SP;
}
/*
* NOTE: We had to eliminate the test for "(accessFlags & PDP11.ACCESS.WRITE)", because DEC's
* "TRAP TEST" expects "TST -(SP)" to trap when SP is 150.
*/
if (reg == 6 && stepSize < 0) {
this.checkStackLimit(mode, this.regsGen[6]);
}
return virtualAddress;
};
@ -2191,23 +2221,23 @@ CPUStatePDP11.prototype.stepCPU = function(nMinCycles)
/*
* Check for any pending traps.
*
* I've moved this TRAP_MASK check BEFORE we decode the next instruction instead
* of immediately AFTER, because the last instruction may have thrown an exception,
* kicking us out before we reach the bottom of this loop.
* I've moved this TRAP_MASK check BEFORE we decode the next instruction instead of immediately AFTER,
* just in case the last instruction threw an exception that kicked us out before we reached the bottom
* of the stepCPU() loop.
*
* Note: I've swapped the order (priority) of the TF and SP traps, based on the PDP-11/20 Handbook.
* TODO: Determine if 1) the 11/20 Handbook was wrong, or 2) the 11/70 really has different priorities.
*/
if (this.opFlags & PDP11.OPFLAG.TRAP_MASK) {
if (this.opFlags & PDP11.OPFLAG.TRAP_MMU) {
this.trap(PDP11.TRAP.MMU, PDP11.REASON.TRAPMMU); // MMU trap has priority
} else {
if (this.opFlags & PDP11.OPFLAG.TRAP_SP) {
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.TRAPSP); // then SP trap
} else {
if (this.opFlags & PDP11.OPFLAG.TRAP_TF) {
this.trap(PDP11.TRAP.BPT, PDP11.REASON.TRAPTF); // and finally a TF trap
}
}
this.trap(PDP11.TRAP.MMU, PDP11.OPFLAG.TRAP_MMU, PDP11.REASON.TRAPMMU);
}
else if (this.opFlags & PDP11.OPFLAG.TRAP_TF) {
this.trap(PDP11.TRAP.BPT, PDP11.OPFLAG.TRAP_TF, PDP11.REASON.TRAPTF);
}
else if (this.opFlags & PDP11.OPFLAG.TRAP_SP) {
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.OPFLAG.TRAP_SP, PDP11.REASON.TRAPSP);
}
this.opFlags &= ~PDP11.OPFLAG.TRAP_MASK;
}
/*
* If we're in the INTQ or WAIT state, see if any interrupts can kick us out of that state.