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More hard disk (AT) and interrupt-handling fixes

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Both real-mode and protected-mode hard disk I/O should be relatively happy now
This commit is contained in:
Jeff Parsons 2014-12-04 11:33:05 -08:00 • committed by jeffpar
commit a5f239fb8d
7 changed files with 124 additions and 73 deletions
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74
modules/pcjs/lib/hdc.js
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@ -1412,7 +1412,7 @@ HDC.prototype.inATCData = function(port, addrFrom)
}
else if (this.drive.ibSector == this.drive.cbSector) {
if (this.messageEnabled(Debugger.MESSAGE.OTHER | Debugger.MESSAGE.HDC)) {
if (this.messageEnabled(Debugger.MESSAGE.DATA | Debugger.MESSAGE.HDC)) {
var sDump = this.drive.disk.dumpSector(this.drive.sector);
if (sDump) this.dbg.message(sDump);
}
@ -1483,7 +1483,7 @@ HDC.prototype.outATCData = function(port, bOut, addrFrom)
}
else if (this.drive.ibSector == this.drive.cbSector) {
if (this.messageEnabled(Debugger.MESSAGE.OTHER | Debugger.MESSAGE.HDC)) {
if (this.messageEnabled(Debugger.MESSAGE.DATA | Debugger.MESSAGE.HDC)) {
var sDump = this.drive.disk.dumpSector(this.drive.sector);
if (sDump) this.dbg.message(sDump);
}
@ -1508,7 +1508,7 @@ HDC.prototype.outATCData = function(port, bOut, addrFrom)
}
} else {
/*
* TODO: What to do about unexpected writes? The number of bytes has exceeded what the command specified.
* TODO: What to do about unexpected writes? No command was specified.
*/
if (DEBUG && this.messageEnabled()) {
this.messageDebugger("HDC.outATCData(" + str.toHexByte(bOut) + "): write without command");
@ -1723,7 +1723,24 @@ HDC.prototype.inATCStatus = function(port, addrFrom)
{
var bIn = this.regStatus;
this.messagePort(port, null, addrFrom, "STATUS", bIn);
if (this.chipset) this.chipset.clearIRR(ChipSet.IRQ.ATC);
/*
* Despite what IBM's documentation for the "Personal Computer AT Fixed Disk and Diskette Drive Adapter"
* (August 31, 1984) says (ie, "A read of the status register clears interrupt request 14"), we cannot
* unilaterally clear the IRQ on any read of STATUS. For starters, that would completely break the PC AT
* ROM BIOS; here's what it does for multi-sector reads:
*
* (1) read sector (REP INSW)
* (2) check STATUS
* (3) check sector count, exit if done
* (4) wait for interrupt
* (5) repeat
*
* Since we set the IRR immediately after (1), we cannot immediately clear the IRR at (2), otherwise the
* interrupt at (4) never happens. So, maybe there are SOME situations where IRR should be cleared on
* a read, but I don't know what they are.
*
* if (this.chipset) this.chipset.clearIRR(ChipSet.IRQ.ATC);
*/
return bIn;
};
@ -1921,7 +1938,29 @@ HDC.prototype.setATCIRR = function(fWrite)
{
if (this.chipset) {
if (!(this.regFDR & HDC.ATC.FDR.INT_DISABLE)) {
this.chipset.setIRR(ChipSet.IRQ.ATC);
/*
* TODO: Determine what the "correct" instruction delay should be here. When the OS/2 1.0 Install Disk
* begins copying files to the hard disk, at one point it performs the following 125-sector write (use the
* Debugger's "m hdc on" and "m pic on" commands to enable HDC and PIC messages, along with "m data on"
* if you also want to see the actual sector data being written):
*
* HDC.doATC(0x30): Write
* HDC.doWrite(0,2:0:5,125)
*
* As the write progresses, you'll notice that the HDC interrupt after each sector occurs at decreasingly
* lower points in the stack, until we eventually start overwriting non-stack data:
*
* getIRRVector(): IRQ 14 interrupting @0090:52A6 stack=0050:1906
* getIRRVector(): IRQ 14 interrupting @0318:196B stack=0050:18D6
* getIRRVector(): IRQ 14 interrupting @0318:196B stack=0050:18A6
* ...
* getIRRVector(): IRQ 14 interrupting @0318:196B stack=0050:1156
*
* At roughly this point, very bad things start happening. I decided to try an arbitrarily large delay
* on the setIRR() call here (120), and the problem vanished, so it seems likely that the OS/2 disk driver
* has a low tolerance for fast controller interrupts during multi-sector operations.
*/
this.chipset.setIRR(ChipSet.IRQ.ATC, 120);
if (DEBUG) this.messageDebugger("HDC.setATCIRR(): enabled", Debugger.MESSAGE.PIC | Debugger.MESSAGE.HDC);
} else {
if (DEBUG) this.messageDebugger("HDC.setATCIRR(): disabled", Debugger.MESSAGE.PIC | Debugger.MESSAGE.HDC);
@ -2375,10 +2414,12 @@ HDC.prototype.doDMAWriteBuffer = function(drive, done)
*
* and we expect the DMA controller to provide C, H, R and N (ie, 4 bytes) for each sector to be formatted.
*
* NOTE: This function is not currently used.
*
* @this {HDC}
* @param {Object} drive
* @param {function(number)} done (dataStatus is XTC.DATA.STATUS_OK or XTC.DATA.STATUS_ERROR; if error, then drive.errorCode should be set as well)
*/
*
HDC.prototype.doDMAFormat = function(drive, done)
{
drive.errorCode = HDC.XTC.DATA.ERR.NOT_READY;
@ -2390,20 +2431,20 @@ HDC.prototype.doDMAFormat = function(drive, done)
drive.abFormat = new Array(4);
drive.bFormatting = true;
drive.cSectorsFormatted = 0;
/*
* We need to reverse the original logic, and default to success unless/until an actual error occurs;
* otherwise dmaWriteFormat() will bail on us. The original approach would work because requestDMA()
* would immediately call us back with fComplete set to true EVEN if the DMA channel was not yet unmasked;
* now the callback is deferred until the DMA channel has been unmasked and the DMA request has finished.
*/
//
// We need to reverse the original logic, and default to success unless/until an actual error occurs;
// otherwise dmaWriteFormat() will bail on us. The original approach would work because requestDMA()
// would immediately call us back with fComplete set to true EVEN if the DMA channel was not yet unmasked;
// now the callback is deferred until the DMA channel has been unmasked and the DMA request has finished.
//
drive.errorCode = HDC.XTC.DATA.ERR.NONE;
this.chipset.connectDMA(ChipSet.DMA_HDC, this, 'dmaWriteFormat', drive);
this.chipset.requestDMA(ChipSet.DMA_HDC, function(fComplete) {
if (!fComplete) {
/*
* If an incomplete request wasn't triggered by an explicit error, then let's make explicit
* (ie, revert to the default failure code that we originally set above).
*/
//
// If an incomplete request wasn't triggered by an explicit error, then let's make explicit
// (ie, revert to the default failure code that we originally set above).
//
if (drive.errorCode == HDC.XTC.DATA.ERR.NONE) {
drive.errorCode = HDC.XTC.DATA.ERR.NOT_READY;
}
@ -2416,6 +2457,7 @@ HDC.prototype.doDMAFormat = function(drive, done)
}
done(drive.errorCode? HDC.XTC.DATA.STATUS_ERROR : HDC.XTC.DATA.STATUS_OK);
};
*/
/**
* readByte(drive, done)