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Improved IOPAGE management

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This commit is contained in:
Jeff Parsons 2016-10-08 11:09:14 -07:00 • committed by Jeff Parsons
commit ae4fbeb489
7 changed files with 469 additions and 422 deletions
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72
modules/pdp11/lib/bus.js
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@ -42,7 +42,7 @@ if (NODE) {
}
/**
* BusPDP11(cpu, dbg)
* BusPDP11(parmsBus, cpu, dbg)
*
* The BusPDP11 component manages physical memory and I/O address spaces.
*
@ -69,8 +69,18 @@ function BusPDP11(parmsBus, cpu, dbg)
this.cpu = cpu;
this.dbg = dbg;
/*
* Supported values for nBusWidth are 16 (default), 18, and 22. This represents the maximum size
* of the bus for the life of the machine, regardless what memory management mode the CPU has enabled.
*/
this.nBusWidth = parmsBus['busWidth'] || 16;
/*
* This controls the location of the IOPAGE (ie, at the top of 16-bit, 18-bit, or 22-bit address range).
* It is managed by setIOPageRange(). initMemory() establishes the default (16).
*/
this.nIOPageRange = 0; // zero means no IOPAGE access (yet)
/*
* Compute all BusPDP11 memory block parameters, based on the width of the bus. The entire
* address space is divided into blocks, using a block size that is (hopefully) appropriate to
@ -130,10 +140,26 @@ function BusPDP11(parmsBus, cpu, dbg)
*/
this.aIOHandlers = [];
this.fIOBreakAll = false;
/*
* Array of RESET notification handlers registered by Device components.
*/
this.afnReset = [];
/*
* Allocate empty Memory blocks to span the entire physical address space.
* Before we can add any memory blocks that declare our component as a custom memory controller,
* we must initialize the array that the getControllerAccess() method supplies to the Memory component.
*/
this.afnIOPage = [
BusPDP11.IOController.readByte,
BusPDP11.IOController.writeByte,
BusPDP11.IOController.readWord,
BusPDP11.IOController.writeWord
];
/*
* We're ready to allocate empty Memory blocks to span the entire physical address space, including the
* initial location of the IOPAGE.
*/
this.initMemory();
@ -142,7 +168,7 @@ function BusPDP11(parmsBus, cpu, dbg)
Component.subclass(BusPDP11);
BusPDP11.IOPAGE_VIRT = 0xE000; /*000160000*/
BusPDP11.IOPAGE_16BIT = 0xE000; /*000160000*/ // eg, PDP-11/20
BusPDP11.IOPAGE_18BIT = 0x3E000; /*000760000*/ // eg, PDP-11/45
BusPDP11.IOPAGE_UNIBUS = 0x3C0000; /*017000000*/
BusPDP11.IOPAGE_22BIT = 0x3FE000; /*017760000*/ // eg, PDP-11/70
@ -365,18 +391,31 @@ BusPDP11.prototype.initMemory = function()
for (var iBlock = 0; iBlock < this.nBlockTotal; iBlock++) {
this.aMemBlocks[iBlock] = block;
}
this.afnIOPage = new Array(4);
this.afnIOPage[0] = BusPDP11.IOController.readByte;
this.afnIOPage[1] = BusPDP11.IOController.writeByte;
this.afnIOPage[2] = BusPDP11.IOController.readWord;
this.afnIOPage[3] = BusPDP11.IOController.writeWord;
/*
* Map IOPAGE at the top of the address space (as determined by nBusWidth), as well as at IOPAGE_VIRT
* (which is the only place that 16-bit code can reach the IOPAGE when memory management is not enabled).
*/
var addr = this.addrTotal - BusPDP11.IOPAGE_LENGTH;
this.addMemory(addr, BusPDP11.IOPAGE_LENGTH, MemoryPDP11.TYPE.CONTROLLER, this);
this.addMemory(BusPDP11.IOPAGE_VIRT, BusPDP11.IOPAGE_LENGTH, MemoryPDP11.TYPE.CONTROLLER, this);
this.setIOPageRange(16);
};
/**
* setIOPageRange(nRange)
*
* We can define the IOPAGE address range with a single number, because the size of the IOPAGE is fixed at 8Kb.
* The bottom of the range is (2 ^ nRange) - IOPAGE_LENGTH, and the top is (2 ^ nRange) - 1.
*
* @this {BusPDP11}
* @param {number} nRange (16, 18 or 22)
*/
BusPDP11.prototype.setIOPageRange = function(nRange)
{
if (nRange != this.nIOPageRange) {
var addr;
if (this.nIOPageRange) {
addr = (1 << this.nIOPageRange) - BusPDP11.IOPAGE_LENGTH;
if (!this.removeMemory(addr, BusPDP11.IOPAGE_LENGTH)) return;
this.nIOPageRange = 0;
}
addr = (1 << nRange) - BusPDP11.IOPAGE_LENGTH;
if (!this.addMemory(addr, BusPDP11.IOPAGE_LENGTH, MemoryPDP11.TYPE.CONTROLLER, this)) return;
this.nIOPageRange = nRange;
}
};
/**
@ -390,6 +429,9 @@ BusPDP11.prototype.initMemory = function()
*/
BusPDP11.prototype.getControllerBuffer = function(addr)
{
/*
* No buffer is required; all accesses go to a registered I/O handler or the bit-bucket.
*/
return [null, 0];
};