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Fixed the LKS Monitor bit

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This commit is contained in:
Jeff 2016-11-08 09:24:01 -08:00 • committed by Jeff Parsons
commit 010ba29b20
11 changed files with 42 additions and 18 deletions
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4
modules/pdp11/README.md
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@ -10,7 +10,7 @@ PDP-11 Machine Emulation Module (PDPjs)
Overview
---
PDPjs, our PDP-11 machine emulation module, is adapted from
the JavaScript [PDP 11/70 Emulator (v1.4)](http://skn.noip.me/pdp11/pdp11.html) written by
the [PDP 11/70 Emulator (v1.4)](http://skn.noip.me/pdp11/pdp11.html) written by
[Paul Nankervis](mailto:paulnank@hotmail.com).
See the list of available [PDP-11 Machines](/devices/pdp11/machine/), which includes a
@ -33,5 +33,7 @@ PDPjs is currently comprised of the following non-shared components, as listed i
* [keyboard.js](/modules/pdp11/lib/keyboard.js)
* [serialport.js](/modules/pdp11/lib/serialport.js)
* [pc11.js](/modules/pdp11/lib/pc11.js)
* [disk.js](/modules/pdp11/lib/disk.js)
* [rl11.js](/modules/pdp11/lib/rl11.js)
* [debugger.js](/modules/pdp11/lib/debugger.js)
* [computer.js](/modules/pdp11/lib/computer.js)

3
modules/pdp11/lib/defines.js
View file

@ -579,7 +579,8 @@ var PDP11 = {
DELAY: 0,
LKS: {
IE: 0x0040, // Interrupt Enable
MON: 0x0080 // Monitor
MON: 0x0080, // Monitor
MASK: 0x00C0 // these are the only bits that can read or written
}
},
PC11: { // High Speed Reader & Punch (PR11 is a Reader-only unit)

25
modules/pdp11/lib/device.js
View file

@ -140,7 +140,7 @@ DevicePDP11.prototype.initBus = function(cmp, bus, cpu, dbg)
*/
DevicePDP11.prototype.reset = function()
{
this.kw11.lks = 0;
this.kw11.lks = PDP11.KW11.LKS.MON;
this.cpu.setTimer(this.kw11.timer, 1000/60, true);
};
@ -148,10 +148,9 @@ DevicePDP11.prototype.reset = function()
* interruptKW11()
*
* We used to call this function only when the the KW11's "Interrupt Enable" bit was set,
* but now we call it at 60Hz regardless. In part, this was so we could piggy-back on
* it to drive display updates, but more importantly, the KW11's "Monitor" bit is supposed
* to be set at the "line frequency" independent of whether KW11 interrupts are enabled.
* So we should actually be more compatible now.
* but now we call it at 60Hz regardless. In part, this was so we could piggy-back on it
* to drive display updates, but more importantly, the KW11's "Monitor" bit is supposed to
* be set at the "line frequency" independent of whether KW11 interrupts are enabled or not.
*
* @this {DevicePDP11}
*/
@ -174,9 +173,12 @@ DevicePDP11.prototype.interruptKW11 = function()
*/
DevicePDP11.prototype.readLKS = function(addr)
{
var result = this.kw11.lks;
this.kw11.lks &= ~PDP11.KW11.LKS.MON;
return result;
/*
* NOTE: The original code always cleared LKS.MON (bit 7) after snapping the value for the read,
* but based on DEC's "Non-Interrupt Mode" programming examples, it's clear that's not how LKS.MON
* operates; if the caller wants to clear it, they must explicitly clear it with a write.
*/
return this.kw11.lks;
};
/**
@ -188,7 +190,12 @@ DevicePDP11.prototype.readLKS = function(addr)
*/
DevicePDP11.prototype.writeLKS = function(data, addr)
{
this.kw11.lks = data & ~PDP11.KW11.LKS.MON;
/*
* NOTE: The original code always cleared LKS.MON (bit 7) as part of any write, but based on DEC's
* "Non-Interrupt Mode" programming examples, which explicitly CLRB after TSTB reveals LKS.MON is set,
* I think that was wrong, and that all a write should do is mask off all the other (non-writable) bits.
*/
this.kw11.lks = data & PDP11.KW11.LKS.MASK;
};
/**