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Simplify the Bus and Memory interfaces slightly, by enabling WORDBUS, which treats all word accesses as aligned; the CPU is has sole responsibility for detecting unaligned word addresses and trapping appropriatelu

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This commit is contained in:
Jeff 2016-10-06 14:17:29 -07:00 • committed by Jeff Parsons
commit 1a1614a648
12 changed files with 444 additions and 398 deletions
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69
modules/pdp11/lib/cpustate.js
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@ -1094,12 +1094,18 @@ CPUStatePDP11.prototype.mapVirtualToPhysical = function(virtualAddress, accessFl
this.mmuLastVirtual = physicalAddress;
if (physicalAddress >= BusPDP11.IOPAGE_VIRT) {
physicalAddress |= BusPDP11.IOPAGE_22BIT;
} else { // no max_memory check in 16 bit mode
}
/*
* I'm moving this alignment test to the CPU->Bus interfaces that read/write physical words;
* hopefully there are no order dependencies on this test.
*
else { // no max_memory check in 16 bit mode
if ((physicalAddress & 1) && !(accessFlags & PDP11.ACCESS.BYTE)) {
this.regErr |= PDP11.CPUERR.ODDADDR;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.ODDMEMADDR);
}
}
*/
} else {
this.mmuLastVirtual = virtualAddress;
page = (virtualAddress >> 13) & this.mmuMask[this.mmuMode];
@ -1118,10 +1124,15 @@ CPUStatePDP11.prototype.mapVirtualToPhysical = function(virtualAddress, accessFl
this.regErr |= PDP11.CPUERR.NOMEMORY;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.NOMEMORY); // KB11-EM does this after ABORT handling - KB11-CM before
}
/*
* I'm moving this alignment test to the CPU->Bus interfaces that read/write physical words;
* hopefully there are no order dependencies on this test.
*
if ((physicalAddress & 1) && !(accessFlags & PDP11.ACCESS.BYTE)) {
this.regErr |= PDP11.CPUERR.ODDADDR;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.ODDMMUADDR);
}
*/
}
switch (pdr & 0x7) {
case 1: // read-only with trap
@ -1190,6 +1201,18 @@ CPUStatePDP11.prototype.mapVirtualToPhysical = function(virtualAddress, accessFl
return physicalAddress;
};
/**
* readByteFromPhysical(physicalAddress) [formerly readByteByAddr]
*
* @this {CPUStatePDP11}
* @param {number} physicalAddress
* @return {number}
*/
CPUStatePDP11.prototype.readByteFromPhysical = function(physicalAddress)
{
return this.bus.getByte(physicalAddress);
};
/**
* readWordFromPhysical(physicalAddress) [formerly readWordByAddr]
*
@ -1199,6 +1222,10 @@ CPUStatePDP11.prototype.mapVirtualToPhysical = function(virtualAddress, accessFl
*/
CPUStatePDP11.prototype.readWordFromPhysical = function(physicalAddress)
{
if (physicalAddress & 0x1) {
this.regErr |= PDP11.CPUERR.ODDADDR;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.ODDMEMADDR);
}
return this.bus.getWord(physicalAddress);
};
@ -1213,30 +1240,6 @@ CPUStatePDP11.prototype.readWordFromVirtual = function(virtualAddress)
return this.readWordFromPhysical(this.mapVirtualToPhysical(virtualAddress, PDP11.ACCESS.READ_WORD));
};
/**
* writeWordToPhysical(physicalAddress, data) [formerly writeWordByAddr]
*
* @this {CPUStatePDP11}
* @param {number} physicalAddress
* @param {number} data
*/
CPUStatePDP11.prototype.writeWordToPhysical = function(physicalAddress, data)
{
this.bus.setWord(physicalAddress, data & 0xffff);
};
/**
* readByteFromPhysical(physicalAddress) [formerly readByteByAddr]
*
* @this {CPUStatePDP11}
* @param {number} physicalAddress
* @return {number}
*/
CPUStatePDP11.prototype.readByteFromPhysical = function(physicalAddress)
{
return this.bus.getByte(physicalAddress);
};
/**
* writeByteToPhysical(physicalAddress, data) [formerly writeByteByAddr]
*
@ -1250,6 +1253,22 @@ CPUStatePDP11.prototype.writeByteToPhysical = function(physicalAddress, data)
this.bus.setByte(physicalAddress, data & 0xff);
};
/**
* writeWordToPhysical(physicalAddress, data) [formerly writeWordByAddr]
*
* @this {CPUStatePDP11}
* @param {number} physicalAddress
* @param {number} data
*/
CPUStatePDP11.prototype.writeWordToPhysical = function(physicalAddress, data)
{
if (physicalAddress & 0x1) {
this.regErr |= PDP11.CPUERR.ODDADDR;
this.trap(PDP11.TRAP.BUS_ERROR, PDP11.REASON.ODDMEMADDR);
}
this.bus.setWord(physicalAddress, data & 0xffff);
};
/**
* popWord()
*