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Improve compatibility of FDC command responses

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This commit is contained in:
Jeff Parsons 2014-10-29 12:45:06 -07:00 • committed by jeffpar
commit 234d6bbfd8
7 changed files with 819 additions and 786 deletions
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121
my_modules/pcjs-client/lib/fdc.js
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@ -1620,7 +1620,7 @@ FDC.prototype.doCmd = function()
var fIRQ = false;
this.regDataIndex = 0;
var bCmd = this.popCmd();
var drive, bDrive, bHeadSelect, bHead, bCylinder, n;
var drive, bDrive, bHead, c, h, r, n;
/*
* NOTE: We currently ignore the FDC.REG_DATA.CMD.SK, FDC.REG_DATA.CMD.MF and FDC.REG_DATA.CMD.MT bits of every command.
@ -1648,7 +1648,7 @@ FDC.prototype.doCmd = function()
case FDC.REG_DATA.CMD.SENSE_DRIVE: // 0x04
bDrive = this.popCmd(FDC.TERMS.DS);
bHeadSelect = (bDrive >> 2) & 0x1;
bHead = (bDrive >> 2) & 0x1;
this.iDrive = (bDrive & 0x3);
drive = this.aDrives[this.iDrive];
this.beginResult();
@ -1657,15 +1657,19 @@ FDC.prototype.doCmd = function()
case FDC.REG_DATA.CMD.WRITE_DATA: // 0x05
case FDC.REG_DATA.CMD.READ_DATA: // 0x06
bDrive = this.popCmd(FDC.TERMS.DS);
bHeadSelect = (bDrive >> 2) & 0x1;
this.iDrive = (bDrive & 0x3);
bDrive = this.popCmd(FDC.TERMS.DS); // Drive Select
bHead = (bDrive >> 2) & 0x1; // isolate HD (Head Select) bits
this.iDrive = (bDrive & 0x3); // isolate DS (Drive Select, aka Unit Select) bits
drive = this.aDrives[this.iDrive];
drive.bHead = bHeadSelect;
drive.bCylinder = this.popCmd(FDC.TERMS.C); // C
bHead = this.popCmd(FDC.TERMS.H); // H
Component.assert(bHead == bHeadSelect);
drive.bSector = this.popCmd(FDC.TERMS.R); // R
drive.bHead = bHead;
c = drive.bCylinder = this.popCmd(FDC.TERMS.C); // C
h = this.popCmd(FDC.TERMS.H); // H
/*
* Controller docs say that H should always match HD, so I assert that, but what if someone
* made a mistake and didn't program them identically -- what would happen? Which should we honor?
*/
Component.assert(h == bHead);
r = drive.bSector = this.popCmd(FDC.TERMS.R); // R
n = this.popCmd(FDC.TERMS.N); // N
drive.nBytes = 128 << n; // 0 => 128, 1 => 256, 2 => 512, 3 => 1024
drive.bSectorEnd = this.popCmd(FDC.TERMS.EOT); // EOT (final sector number on a cylinder)
@ -1675,14 +1679,7 @@ FDC.prototype.doCmd = function()
this.doRead(drive);
else
this.doWrite(drive);
this.beginResult();
this.pushST0(drive);
this.pushST1(drive);
this.pushST2(drive);
this.pushResult(drive.bCylinder, FDC.TERMS.C);
this.pushResult(drive.bHead, FDC.TERMS.H);
this.pushResult(drive.bSector, FDC.TERMS.R);
this.pushResult(n, FDC.TERMS.N);
this.pushResults(drive, bCmd, bHead, c, h, r, n);
fIRQ = true;
break;
@ -1731,11 +1728,12 @@ FDC.prototype.doCmd = function()
* To start, we'll focus on making this work in the normal case (80-track diskette in 80-track drive).
*/
bDrive = this.popCmd(FDC.TERMS.DS);
bHeadSelect = (bDrive >> 2) & 0x1;
bHead = (bDrive >> 2) & 0x1;
this.iDrive = (bDrive & 0x3);
drive = this.aDrives[this.iDrive];
drive.bHead = bHeadSelect;
drive.bSector = 1;
c = drive.bCylinder;
h = drive.bHead = bHead;
r = drive.bSector = 1;
n = 0;
drive.resCode = FDC.REG_DATA.RES.NONE;
if (drive.disk && (drive.sector = drive.disk.seek(drive.bCylinder, drive.bHead, drive.bSector))) {
@ -1746,45 +1744,34 @@ FDC.prototype.doCmd = function()
*/
drive.resCode = FDC.REG_DATA.RES.NO_DATA | FDC.REG_DATA.RES.INCOMPLETE;
}
this.pushST0(drive);
this.pushST1(drive);
this.pushST2(drive);
this.pushResult(drive.bCylinder, FDC.TERMS.C);
this.pushResult(drive.bHead, FDC.TERMS.H);
this.pushResult(drive.bSector, FDC.TERMS.R);
this.pushResult(n, FDC.TERMS.N);
this.pushResults(drive, bCmd, bHead, c, h, r, n);
fIRQ = true;
break;
case FDC.REG_DATA.CMD.FORMAT_TRACK: // 0x0D
bDrive = this.popCmd(FDC.TERMS.DS);
bHeadSelect = (bDrive >> 2) & 0x1;
bHead = (bDrive >> 2) & 0x1;
this.iDrive = (bDrive & 0x3);
drive = this.aDrives[this.iDrive];
drive.bHead = bHeadSelect;
c = drive.bCylinder;
h = drive.bHead = bHead;
r = 1;
n = this.popCmd(FDC.TERMS.N); // N
drive.nBytes = 128 << n; // 0 => 128, 1 => 256, 2 => 512, 3 => 1024 (bytes/sector)
drive.bSectorEnd = this.popCmd(FDC.TERMS.SC); // SC (sectors/track)
this.popCmd(FDC.TERMS.GPL); // GPL (spacing between sectors, excluding VCO Sync Field; 3)
drive.bFiller = this.popCmd(FDC.TERMS.D); // D (filler byte)
this.doFormat(drive);
this.beginResult();
this.pushST0(drive);
this.pushST1(drive);
this.pushST2(drive);
this.pushResult(drive.bCylinder, FDC.TERMS.C);
this.pushResult(drive.bHead, FDC.TERMS.H);
this.pushResult(drive.bSector, FDC.TERMS.R);
this.pushResult(n, FDC.TERMS.N);
this.pushResults(drive, bCmd, bHead, c, h, r, n);
fIRQ = true;
break;
case FDC.REG_DATA.CMD.SEEK: // 0x0F
bDrive = this.popCmd(FDC.TERMS.DS);
bHeadSelect = (bDrive >> 2) & 0x1;
bHead = (bDrive >> 2) & 0x1;
this.iDrive = (bDrive & 0x3);
drive = this.aDrives[this.iDrive];
drive.bHead = bHeadSelect;
drive.bHead = bHead;
/*
* As discussed in initDrive(), we can no longer simply set bCylinder to the specified NCN;
* instead, we must calculate the delta between bCylinderSeek and the NCN, and adjust bCylinder
@ -1794,11 +1781,11 @@ FDC.prototype.doCmd = function()
* be allowed to exceed the physical boundaries of the drive (ie, never lower than 0, and never
* greater than or equal to nCylinders).
*/
bCylinder = this.popCmd(FDC.TERMS.NCN);
drive.bCylinder += bCylinder - drive.bCylinderSeek;
c = this.popCmd(FDC.TERMS.NCN);
drive.bCylinder += c - drive.bCylinderSeek;
if (drive.bCylinder < 0) drive.bCylinder = 0;
if (drive.bCylinder >= drive.nCylinders) drive.bCylinder = drive.nCylinders - 1;
drive.bCylinderSeek = bCylinder;
drive.bCylinderSeek = c;
drive.resCode = FDC.REG_DATA.RES.SEEK_END;
/*
* TODO: To properly support ALL the ST3 result bits (not just TRACK0), we need a resCode
@ -1837,6 +1824,50 @@ FDC.prototype.doCmd = function()
}
};
/**
* pushResults(drive, bCmd, bHead, c, h, r, n)
*
* @param {Object} drive
* @param {number} bCmd
* @param {number} bHead
* @param {number} c
* @param {number} h
* @param {number} r
* @param {number} n
*/
FDC.prototype.pushResults = function(drive, bCmd, bHead, c, h, r, n)
{
this.beginResult();
this.pushST0(drive);
this.pushST1(drive);
this.pushST2(drive);
/*
* NOTE: I used to set the following C/H/R/N results using the values that advanceSector() had "advanced"
* them to, which seemed logical but was technically incorrect. For non-multi-track reads, they should match
* the programmed C/H/R/N values, except when EOT has been reached, in which case C = C + 1 and R = 1.
*
* For multi-track, the LSB of H should be complemented whenever EOT has been reached, which I "informally"
* detect by testing if the drive's current bCylinder and/or bHead positions advanced to a new cylinder or head,
* and apparently, C should never be advanced if H was initially 0.
*
* I don't do strict EOT comparisons here or elsewhere, because it allows the controller to work with a wider
* range of disks (eg, "fake" XDF disk images that contain 23 512-byte sectors/track).
*/
var i = 0;
if (c != drive.bCylinder || h != drive.bHead) {
i = r = 1;
}
if (bCmd & FDC.REG_DATA.CMD.MT) {
h ^= i;
if (!bHead) i = 0;
}
c += i;
this.pushResult(c, FDC.TERMS.C); // formerly drive.bCylinder
this.pushResult(h, FDC.TERMS.H); // formerly drive.bHead
this.pushResult(r, FDC.TERMS.R); // formerly drive.bSector
this.pushResult(n, FDC.TERMS.N);
};
/**
* popCmd(name)
*
@ -1848,7 +1879,7 @@ FDC.prototype.popCmd = function(name)
{
Component.assert((!this.regDataIndex || name !== undefined) && this.regDataIndex < this.regDataTotal);
var bCmd = this.regDataArray[this.regDataIndex];
if (DEBUG && DEBUGGER && this.dbg && this.dbg.messageEnabled((this.regDataIndex > 0? FDC.MESSAGE_PORT : 0) | FDC.MESSAGE_FDC)) {
if (DEBUG && DEBUGGER && this.dbg && this.dbg.messageEnabled(FDC.MESSAGE_FDC)) {
var bCmdMasked = bCmd & FDC.REG_DATA.CMD.MASK;
if (!name && !this.regDataIndex && FDC.aCmdInfo[bCmdMasked]) name = FDC.aCmdInfo[bCmdMasked].name;
this.dbg.message("FDC.CMD[" + (name || this.regDataIndex) + "]: 0x" + str.toHexByte(bCmd));
@ -1902,7 +1933,7 @@ FDC.prototype.beginResult = function()
*/
FDC.prototype.pushResult = function(bResult, name)
{
if (DEBUG) this.messageDebugger("FDC.RES[" + (name || this.regDataTotal) + "]: 0x" + str.toHexByte(bResult), FDC.MESSAGE_PORT | FDC.MESSAGE_FDC);
if (DEBUG) this.messageDebugger("FDC.RES[" + (name || this.regDataTotal) + "]: 0x" + str.toHexByte(bResult), FDC.MESSAGE_FDC);
this.regDataArray[this.regDataTotal++] = bResult;
};