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debugger.js
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/**
* @fileoverview Implements the PCx86 Debugger component
* @author Jeff Parsons <[email protected]>
* @copyright © 2012-2025 Jeff Parsons
* @license MIT <https://www.pcjs.org/LICENSE.txt>
*
* This file is part of PCjs, a computer emulation software project at <https://www.pcjs.org>.
*/
import Interrupts from "./interrupts.js";
import Memoryx86 from "./memory.js";
import MESSAGE from "./message.js";
import Segx86 from "./segx86.js";
import X86 from "./x86.js";
import Component from "../../../modules/v2/component.js";
import DbgLib from "../../../modules/v2/dbglib.js";
import Keys from "../../../modules/v2/keys.js";
import State from "../../../modules/v2/state.js";
import StrLib from "../../../modules/v2/strlib.js";
import UsrLib from "../../../modules/v2/usrlib.js";
import WebLib from "../../../modules/v2/weblib.js";
import { APPCLASS, APPNAME, APPVERSION, BACKTRACK, BYTEARRAYS, COMPILED, DEBUG, DEBUGGER, I386, MAXDEBUG, PREFETCH, SYMBOLS, TYPEDARRAYS, globals } from "./defines.js";
/**
* @typedef {Object} DbgAddrx86
* @property {number} [off]
* @property {number} [sel]
* @property {number} [addr]
* @property {number} [type]
* @property {boolean} [fData32]
* @property {boolean} [fAddr32]
* @property {boolean} [fData32Orig]
* @property {boolean} [fAddr32Orig]
* @property {boolean} [fTempBreak]
* @property {string} [sCmd]
* @property {Array.<string>} [aCmds]
* @property {number} [nCPUCycles] (added to DbgAddrx86 objects stored in history buffer)
* @property {number} [nDebugCycles] (added to DbgAddrx86 objects stored in history buffer)
* @property {number} [nDebugState] (added to DbgAddrx86 objects stored in history buffer)
*/
/**
* @typedef {Object} VectorBP
* @property {number} [vector]
* @property {number} [type]
* @property {DbgAddrx86} [dbgAddr]
*/
/**
* Debugger Breakpoint Tips
*
* Here's an example of our powerful new breakpoint command capabilities:
*
* bp 0397:022B "?'GlobalAlloc(wFlags:[ss:sp+8],dwBytes:[ss:sp+6][ss:sp+4])';g [ss:sp+2]:[ss:sp] '?ax;if ax'"
*
* The above breakpoint will display a pleasing "GlobalAlloc()" string containing the current
* stack parameters, and will briefly stop execution on the return to print the result in AX,
* halting the CPU whenever AX is zero (the default behavior of "if" whenever the expression is
* false is to look for an "else" and automatically halt when there is no "else").
*
* How do you figure out where the code for GlobalAlloc is in the first place? You need to have
* BACKTRACK support enabled (which currently means running the non-COMPILED version), so that as
* the Disk component loads disk images, it will automatically extract symbolic information from all
* "NE" (New Executable) binaries on those disks, which the Debugger's "dt" command can then search
* for you; eg:
*
* ## dt globalalloc
* GLOBALALLOC: KRNL386.EXE 0001:022B len 0xC570
*
* And then you just need to do a bit more sleuthing to find the right CODE segment. And that just
* got easier, now that the PCx86 Debugger mimics portions of the Windows Debugger INT 0x41 interface;
* see intWindowsDebugger() for details. So even if you neglect to run WDEB386.EXE /E inside the
* machine before running Windows, you should still see notifications like:
*
* KERNEL!undefined code(0001)=#0397 len 0000C580
*
* in the PCx86 Debugger output window, as segments are being loaded by the Windows kernel.
*/
/**
* @class Debuggerx86
* @unrestricted (allows the class to define properties, both dot and named, outside of the constructor)
*/
export default class Debuggerx86 extends DbgLib {
/**
* Debuggerx86(parmsDbg)
*
* The Debuggerx86 component is an optional component that implements a variety of user commands
* for controlling the CPU, dumping and editing memory, etc.
*
* Debuggerx86 extends the shared Debugger component and supports the following optional (parmsDbg)
* properties:
*
* commands: string containing zero or more commands, separated by ';'
*
* messages: string containing zero or more message categories to enable;
* multiple categories must be separated by ',' or ';'. Parsed by messageInit().
*
* @this {Debuggerx86}
* @param {Object} parmsDbg
*/
constructor(parmsDbg)
{
super("Debugger", parmsDbg, -1);
if (DEBUGGER) {
/**
* Default number of hex chars in a register and a linear address (ie, for real-mode);
* updated by initBus().
*/
this.cchReg = 4;
this.cchAddr = 5;
this.maskAddr = 0xfffff;
/**
* Most commands that require an address call parseAddr(), which defaults to dbgAddrNextCode
* or dbgAddrNextData when no address has been given. doDump() and doUnassemble(), in turn,
* update dbgAddrNextData and dbgAddrNextCode, respectively, when they're done.
*
* All dbgAddr variables contain properties off, sel, and addr, where sel:off represents the
* segmented address and addr is the corresponding linear address (if known). For certain
* segmented addresses (eg, breakpoint addresses), we pre-compute the linear address and save
* that in addr, so that the breakpoint will still operate as intended even if the mode changes
* later (eg, from real-mode to protected-mode).
*
* Finally, for TEMPORARY breakpoint addresses, we set fTempBreak to true, so that they can be
* automatically cleared when they're hit.
*/
this.dbgAddrNextCode = this.newAddr(0, 0);
this.dbgAddrNextData = this.newAddr(0, 0);
this.dbgAddrAssemble = this.newAddr(0, 0);
/**
* aSymbolTable is an array of SymbolTable objects, one per ROM or other chunk of address space,
* where each object contains the following properties:
*
* sModule
* nSegment
* sel
* off
* addr (physical address, if any; eg, symbols for a ROM)
* len
* aSymbols
* aOffsets
*
* See addSymbols() for more details, since that's how callers add sets of symbols to the table.
*/
this.aSymbolTable = [];
/**
* clearBreakpoints() initializes the breakpoints lists: aBreakExec is a list of addresses
* to halt on whenever attempting to execute an instruction at the corresponding address,
* and aBreakRead and aBreakWrite are lists of addresses to halt on whenever a read or write,
* respectively, occurs at the corresponding address.
*
* NOTE: Curiously, after upgrading the Google Closure Compiler from v20141215 to v20150609,
* the resulting compiled code would crash in clearBreakpoints(), because the (renamed) aBreakRead
* property was already defined. To eliminate whatever was confusing the Closure Compiler, I've
* explicitly initialized all the properties that clearBreakpoints() (re)initializes.
*/
this.aBreakExec = this.aBreakRead = this.aBreakWrite = [];
this.clearBreakpoints();
/**
* The new "bn" command allows you to specify a number of instructions to execute and then stop;
* "bn 0" disables any outstanding count.
*/
this.nBreakIns = 0;
/**
* A new breakpoint command, "bv", allows you to monitor an interrupt vector. Vector breakpoints
* don't simply monitor "INT" instructions; they also snapshot the vector address when the "bv"
* command is issued and monitor execution of that address. The array is filled with VectorBP objects,
* which contain vector and dbgAddr properties.
*/
this.aVectorBP = [];
this.vectorHalt = true; // true to halt on vector breakpoints
this.vectorSkip = -1;
this.vectorTrace = -1; // >= 0 whenever a vector has been traced
/**
* Execution history is allocated by historyInit() whenever checksEnabled() conditions change.
* Execution history is updated whenever the CPU calls checkInstruction(), which will happen
* only when checksEnabled() returns true (eg, whenever one or more breakpoints have been set).
* This ensures that, by default, the CPU runs as fast as possible.
*/
this.historyInit();
/**
* Initialize Debugger message and command support
*/
this.afnDumpers = {};
this.messageInit(parmsDbg['messages']);
this.sCommandsInit = parmsDbg['commands'];
/**
* Make it easier to access Debugger commands from an external REPL, like the WebStorm "live" console
* window; eg:
*
* pcx86('r')
* pcx86('dw 0:0')
* pcx86('h')
* ...
*/
let dbg = this;
if (globals.window[APPCLASS] === undefined) {
globals.window[APPCLASS] = function(s) { return dbg.doCommands(s); };
}
} // endif DEBUGGER
}
/**
* initBus(bus, cpu, dbg)
*
* @this {Debuggerx86}
* @param {Computer} cmp
* @param {Busx86} bus
* @param {CPUx86} cpu
* @param {Debuggerx86} dbg
*/
initBus(cmp, bus, cpu, dbg)
{
this.bus = bus;
this.cpu = cpu;
this.cmp = cmp;
this.fdc = cmp.getMachineComponent("FDC", false);
this.hdc = cmp.getMachineComponent("HDC", false);
this.mouse = cmp.getMachineComponent("Mouse", false);
/**
* Re-initialize Debugger message and command support as needed
*/
let sMessages = cmp.getMachineParm('messages');
if (sMessages) this.messageInit(sMessages);
this.sCommandsInit = cmp.getMachineParm('commands') || this.sCommandsInit;
/**
* If CHIPSET or VIDEO messages are enabled at startup, we enable ChipSet or Video diagnostic info in
* the instruction history buffer as appropriate.
*/
if (this.messageEnabled(MESSAGE.CHIPSET)) {
this.chipset = cmp.getMachineComponent("ChipSet");
}
else if (this.messageEnabled(MESSAGE.VIDEO)) {
this.video = cmp.getMachineComponent("Video");
}
this.cchAddr = bus.getWidth() >> 2;
this.maskAddr = bus.nBusLimit;
/**
* Allocate a special segment "register", for use whenever a requested selector is not currently loaded
*/
this.segDebugger = new Segx86(this.cpu, Segx86.ID.DBG, "DBG");
this.aaOpDescs = Debuggerx86.aaOpDescs;
if (this.cpu.model >= X86.MODEL_80186) {
this.aaOpDescs = Debuggerx86.aaOpDescs.slice();
this.aaOpDescs[0x0F] = Debuggerx86.aOpDescUndefined;
if (this.cpu.model >= X86.MODEL_80286) {
/**
* TODO: Consider whether the aOpDesc0F table should be split in two: one for 80286-only instructions,
* and one for both 80286 and 80386. For now, the Debugger is not as strict as the CPUx86 is about
* the instructions it supports for each type of CPU, in part because an 80286 machine could still be
* presented with 80386-only code that is simply "skipped over" when then CPU doesn't support it.
*
* Obviously I'm not being entirely consistent, since I don't disassemble *any* 0x0F opcodes for any
* pre-80286 CPUs. But at least I'm being up front about it.
*/
this.aaOpDescs[0x0F] = Debuggerx86.aOpDesc0F;
if (I386 && this.cpu.model >= X86.MODEL_80386) this.cchReg = 8;
}
}
this.messageDump(MESSAGE.BUS, function onDumpBus(asArgs) { dbg.dumpBus(asArgs); });
this.messageDump(MESSAGE.DESC, function onDumpSel(asArgs) { dbg.dumpSel(asArgs); });
this.messageDump(MESSAGE.DOS, function onDumpDOS(asArgs) { dbg.dumpDOS(asArgs); });
this.messageDump(MESSAGE.MEM, function onDumpMem(asArgs) { dbg.dumpMem(asArgs); });
this.messageDump(MESSAGE.TSS, function onDumpTSS(asArgs) { dbg.dumpTSS(asArgs); });
let fSymbols = cmp.getMachineBoolean('symbols');
if (DEBUG && fSymbols !== false || fSymbols) {
if (Interrupts.WINDBG.ENABLED || Interrupts.WINDBGRM.ENABLED) {
this.fWinDbg = null;
this.cTrapFaults = 0;
this.fIgnoreNextCheckFault = false;
this.cpu.addIntNotify(Interrupts.WINCB.VECTOR, this.intWindowsCallBack.bind(this));
this.cpu.addIntNotify(Interrupts.WINDBG.VECTOR, this.intWindowsDebugger.bind(this));
}
if (Interrupts.WINDBGRM.ENABLED) {
this.fWinDbgRM = null;
this.cpu.addIntNotify(Interrupts.WINDBGRM.VECTOR, this.intWindowsDebuggerRM.bind(this));
}
}
this.setReady();
}
/**
* addSegmentInfo(dbgAddr, nSegment, sel, fCode, fPrint)
*
* @this {Debuggerx86}
* @param {DbgAddrx86} dbgAddr (address of module name)
* @param {number} nSegment (logical segment number)
* @param {number} sel (current selector)
* @param {boolean} fCode (true if code segment, false if data segment)
* @param {boolean|null} [fPrint] (false means we're merely monitoring, so let WDEB386 print its own notifications)
*/
addSegmentInfo(dbgAddr, nSegment, sel, fCode, fPrint)
{
let sModule = this.getSZ(dbgAddr);
let seg = this.getSegment(sel);
let len = seg? seg.limit + 1 : 0;
let sSection = (fCode? "_CODE" : "_DATA") + StrLib.toHex(nSegment, 2);
if (fPrint) {
this.printf(MESSAGE.DEBUG, "%s %s(%04X)=#%04X len %0X\n", sModule, (fCode? "code" : "data"), nSegment, sel, len);
}
let off = 0;
let aSymbols = this.findModuleInfo(sModule, nSegment);
aSymbols[sModule + sSection] = off;
this.addSymbols(sModule, nSegment, sel, off, null, len, aSymbols);
}
/**
* removeSegmentInfo(sel, fPrint)
*
* @this {Debuggerx86}
* @param {number} sel
* @param {boolean|null} [fPrint] (false means we're merely monitoring OR we don't really care about these notifications)
*/
removeSegmentInfo(sel, fPrint)
{
let sModuleRemoved = this.removeSymbols(null, sel);
if (fPrint) {
if (sModuleRemoved) {
this.printf(MESSAGE.DEBUG, "%s #%04X removed\n", sModuleRemoved, sel);
} else {
this.printf(MESSAGE.DEBUG, "unable to remove module for segment #%04X\n", sel);
}
}
}
/**
* addSectionInfo(dbgAddr, fCode, fPrint)
*
* @this {Debuggerx86}
* @param {DbgAddrx86} dbgAddr (address of D386_Device_Params)
* @param {boolean} fCode (true if code section, false if data section)
* @param {boolean|null} [fPrint] (false means we're merely monitoring, so let WDEB386 print its own notifications)
*/
addSectionInfo(dbgAddr, fCode, fPrint)
{
let nSegment = this.getShort(dbgAddr, 2);
let sel = this.getShort(dbgAddr, 2);
let off = this.getLong(dbgAddr, 4);
let len = this.getLong(dbgAddr, 4);
let dbgAddrModule = this.newAddr(this.getLong(dbgAddr, 4), this.getShort(dbgAddr, 2));
let dbgAddrParent = this.newAddr(this.getLong(dbgAddr, 4), this.getShort(dbgAddr, 2));
// sel = this.getShort(dbgAddr, 2) || sel;
let sParent = this.getSZ(dbgAddrParent).toUpperCase();
let sModule = this.getSZ(dbgAddrModule).toUpperCase();
if (sParent == sModule) {
sParent = "";
} else {
sParent += '!';
}
let sSection = (fCode? "_CODE" : "_DATA") + StrLib.toHex(nSegment, 2);
/**
* Mimics WDEB386 output, except that WDEB386 only displays a linear address, omitting the selector.
*/
if (fPrint) {
this.printf(MESSAGE.DEBUG, "%s%s %s(%04X)=%04X:%0X len %0X\n", sParent, sModule, (fCode? "code" : "data"), nSegment, sel, off, len);
}
/**
* TODO: Add support for 32-bit symbols; findModuleInfo() relies on Disk.getModuleInfo(),
* and the Disk component doesn't yet know how to parse 32-bit executables.
*/
let aSymbols = this.findModuleInfo(sModule, nSegment);
aSymbols[sModule + sSection] = off;
this.addSymbols(sModule, nSegment, sel, off, null, len, aSymbols);
}
/**
* removeSectionInfo(nSegment, dbgAddr, fPrint)
*
* @this {Debuggerx86}
* @param {number} nSegment (logical segment number)
* @param {DbgAddrx86} dbgAddr (address of module)
* @param {boolean|null} [fPrint] (false means we're merely monitoring OR we don't really care about these notifications)
*/
removeSectionInfo(nSegment, dbgAddr, fPrint)
{
let sModule = this.getSZ(dbgAddr).toUpperCase();
let sModuleRemoved = this.removeSymbols(sModule, nSegment);
if (fPrint) {
if (sModuleRemoved) {
this.printf(MESSAGE.DEBUG, "%s %04X removed\n", sModule, nSegment);
} else {
this.printf(MESSAGE.DEBUG, "unable to remove %s for section %04X\n", sModule, nSegment);
}
}
}
/**
* intWindowsCallBack()
*
* This intercepts calls to Windows callback addresses, which use INT 0x30 (aka Transfer Space Faults).
*
* We're only interested in one particular callback: the VW32_Int41Dispatch (0x002A002A) that KERNEL32
* issues as 32-bit executable sections are loaded.
*
* At the time that INT 0x30 occurs, a far 32-bit call has been made, preceded by a near 32-bit call,
* preceded by a 32-bit push of the Windows Debugger function # that would normally be in EAX if this had
* been an actual INT 0x41.
*
* NOTE: Regardless whether we're "handling" INT 0x41 or merely "monitoring" INT 0x41, as far as THIS
* interrupt is concerned, we always let the system process it, because execution never continues at the
* instruction following an INT 0x30; in fact, execution doesn't even continue after the far 32-bit call
* (even though the kernel places a "RET 4" after that call). So, rather than recreate all that automatic
* address popping, we let the system do it for us, since it's designed to work whether a debugger (eg,
* WDEB386's DEBUG VxD) is installed or not.
*
* TODO: Consider "consuming" all VW32_Int41Dispatch callbacks, because the Windows 95 kernel goes to
* great effort to pass those requests on to the DEBUG VxD, which end up going nowhere when the VxD isn't
* loaded (to load it, you must either run WDEB386.EXE or install the VxD via SYSTEM.INI). Regrettably,
* Windows 95 assumes that if WDEB386 support is present, then a DEBUG VxD must be present as well.
*
* @this {Debuggerx86}
* @param {number} addr
* @returns {boolean} (true to proceed with the INT 0x30 software interrupt)
*/
intWindowsCallBack(addr)
{
let cpu = this.cpu;
if (this.fWinDbg != null && cpu.regEAX == 0x002A002A) {
let DX = cpu.regEDX & 0xffff;
let SI = cpu.regESI & 0xffff;
let dbgAddr = this.newAddr(cpu.getSP() + 0x0C, cpu.getSS());
let EAX = this.getLong(dbgAddr);
switch(EAX) {
case Interrupts.WINDBG.LOADSEG32:
/**
* SI == segment type:
* 0x0 code selector
* 0x1 data selector
* DX:EBX -> D386_Device_Params structure (see addSectionInfo() for details)
*/
this.addSectionInfo(this.newAddr(cpu.regEBX, DX), !SI, this.fWinDbg);
break;
}
}
return true;
}
/**
* intWindowsDebugger()
*
* This intercepts calls to the Windows Debugger protected-mode interface (INT 0x41).
*
* It's enabled if Interrupts.WINDBG.ENABLED is true, but it must ALSO be enabled if
* Interrupts.WINDBGRM.ENABLED is true, because if the latter decides to respond to requests,
* then we must start responding, too. Windows assumes that if INT 0x68 support is present,
* then INT 0x41 support must be present as well.
*
* That is why intWindowsDebuggerRM() will also set this.fWinDbg to true: we MUST return false
* for all INT 0x41 requests, so that all requests are consumed, since there's no guarantee
* that a valid INT 0x41 handler will exist inside the machine.
*
* @this {Debuggerx86}
* @param {number} addr
* @returns {boolean} (true to proceed with the INT 0x41 software interrupt, false to skip)
*/
intWindowsDebugger(addr)
{
let dbgAddr;
let cpu = this.cpu;
let AX = cpu.regEAX & 0xffff;
let BX = cpu.regEBX & 0xffff;
let CX = cpu.regECX & 0xffff;
let DX = cpu.regEDX & 0xffff;
let SI = cpu.regESI & 0xffff;
let DI = cpu.regEDI & 0xffff;
let ES = cpu.segES.sel;
if (this.fWinDbg == null) {
if (AX == Interrupts.WINDBG.IS_LOADED) {
/**
* We're only going to respond to this function if no one else did, in which case,
* we'll set fWinDbg to true and handle additional notifications.
*/
cpu.addIntReturn(addr, function(dbg) {
return function onInt41Return(nLevel) {
if ((cpu.regEAX & 0xffff) != Interrupts.WINDBG.LOADED) {
cpu.regEAX = (cpu.regEAX & ~0xffff) | Interrupts.WINDBG.LOADED;
/**
* TODO: We need a DEBUGGER message category; using the MEM category for now.
*/
dbg.printf(MESSAGE.DEBUG, "INT 41 handling enabled\n");
dbg.fWinDbg = true;
} else {
dbg.printf(MESSAGE.DEBUG, "INT 41 monitoring enabled\n");
dbg.fWinDbg = false;
}
};
}(this));
}
return true;
}
/**
* NOTE: If this.fWinDbg is true, then all cases should return false, because we're taking full
* responsibility for all requests (don't assume there's valid interrupt handler inside the machine).
*/
switch(AX) {
case Interrupts.WINDBG.ISCHAR: // 0x0003 (called regularly by Win31)
break;
case Interrupts.WINDBG.FORCEDGO16: // 0x0040 (called regularly by Win31)
/**
* 2023 Update: It's been a while since I've tried doing a clean install of Windows 95, and this was
* firing incessantly. TODO: Investigate who/what is triggering this later.
*/
break;
case Interrupts.WINDBG.IS_LOADED: // 0x004F
if (this.fWinDbg) {
cpu.regEAX = (cpu.regEAX & ~0xffff) | Interrupts.WINDBG.LOADED;
this.printf(MESSAGE.DEBUG, "INT 41 handling enabled\n");
}
break;
case Interrupts.WINDBG.LOADSEG: // 0x0050
this.addSegmentInfo(this.newAddr(DI, ES), BX+1, CX, !(SI & 0x1), this.fWinDbg);
break;
case Interrupts.WINDBG.FREESEG: // 0x0052
this.removeSegmentInfo(BX, this.fWinDbg);
break;
case Interrupts.WINDBG.KRNLVARS: // 0x005A
/**
* BX = version number of this data (0x3A0)
* DX:CX points to:
* WORD hGlobalHeap ****
* WORD pGlobalHeap ****
* WORD hExeHead ****
* WORD hExeSweep
* WORD topPDB
* WORD headPDB
* WORD topsizePDB
* WORD headTDB ****
* WORD curTDB ****
* WORD loadTDB
* WORD LockTDB
* WORD SelTableLen ****
* DWORD SelTableStart ****
*/
break;
case Interrupts.WINDBG.RELSEG: // 0x005C
case Interrupts.WINDBG.EXITCALL: // 0x0062
case Interrupts.WINDBG.LOADDLL: // 0x0064
case Interrupts.WINDBG.DELMODULE: // 0x0065
case Interrupts.WINDBG.UNKNOWN66: // 0x0066
case Interrupts.WINDBG.UNKNOWN67: // 0x0067
/**
* TODO: Figure out what to do with these notifications, if anything
*/
break;
case Interrupts.WINDBG.LOADHIGH: // 0x005D
case Interrupts.WINDBG.REGDOTCMD: // 0x0070
case Interrupts.WINDBG.CONDBP: // 0xF001
break;
case Interrupts.WINDBG.CHECKFAULT: // 0x007F
if (this.fWinDbg) {
/**
* AX == 0 means handle fault normally, 1 means issue TRAPFAULT
*/
cpu.regEAX = (cpu.regEAX & ~0xffff) | (this.fIgnoreNextCheckFault? 0 : 1);
this.printf(MESSAGE.DEBUG, "INT 41 CHECKFAULT: fault=%04X type=%04X trap=%b\n", BX, CX, !this.fIgnoreNextCheckFault);
}
break;
case Interrupts.WINDBG.TRAPFAULT: // 0x0083
/**
* If we responded with AX == 1 to a preceding CHECKFAULT notification, then we should receive the
* following TRAPFAULT notification; additionally, a TRAPFAULT notification may be issued without
* any CHECKFAULT warning if the user was presented with a fault dialog containing a "Debug" button,
* and the user clicked it.
*
* Regardless, whenever we receive this notification, we allocate a temporary breakpoint at the
* reported fault address.
*/
if (this.fWinDbg) {
dbgAddr = this.newAddr(cpu.regEDX, CX);
if (!this.cTrapFaults++) {
this.printf("INT 41 TRAPFAULT: fault=%04X error=%08X addr=%s\n", BX, cpu.regESI, this.toHexAddr(dbgAddr));
this.addBreakpoint(this.aBreakExec, dbgAddr, true);
this.historyInit(true); // temporary breakpoints don't normally trigger history, but in this case, we want it to
} else {
this.printf("TRAPFAULT failed\n");
this.findBreakpoint(this.aBreakExec, dbgAddr, true, true, true);
this.cTrapFaults = 0;
this.stopCPU();
}
}
break;
case Interrupts.WINDBG.GETSYMBOL: // 0x008D
if (this.fWinDbg) cpu.regEAX = (cpu.regEAX & ~0xffff)|1; // AX == 1 means not found
break;
case Interrupts.WINDBG.LOADSEG32: // 0x0150
/**
* SI == segment type:
* 0x0 code selector
* 0x1 data selector
* DX:EBX -> D386_Device_Params structure (see addSectionInfo() for details)
*/
this.addSectionInfo(this.newAddr(cpu.regEBX, DX), !SI, this.fWinDbg);
break;
case Interrupts.WINDBG.FREESEG32: // 0x0152
/**
* BX == segment number
* DX:EDI -> module name
*/
this.removeSectionInfo(BX, this.newAddr(cpu.regEDI, DX), this.fWinDbg);
break;
case Interrupts.WINDBG.FORCEDBP: // 0xF002
break;
default:
if (this.fWinDbg) {
this.printf(MESSAGE.DEBUG, "INT 41: AX=%04X (unhandled)\n", AX);
}
break;
}
/**
* Let's try to limit the scope of any "gt" command by resetting this flag after any INT 0x41
*/
this.fIgnoreNextCheckFault = false;
return !this.fWinDbg;
}
/**
* intWindowsDebuggerRM()
*
* This intercepts calls to the Windows Debugger real-mode interface (INT 0x68).
*
* @this {Debuggerx86}
* @param {number} addr
* @returns {boolean} (true to proceed with the INT 0x68 software interrupt, false to skip)
*/
intWindowsDebuggerRM(addr)
{
let cpu = this.cpu;
let AL = cpu.regEAX & 0xff;
let AH = (cpu.regEAX >> 8) & 0xff;
let BX = cpu.regEBX & 0xffff;
let CX = cpu.regECX & 0xffff;
let DX = cpu.regEDX & 0xffff;
let DI = cpu.regEDI & 0xffff;
let ES = cpu.segES.sel;
if (this.fWinDbgRM == null) {
if (AH == Interrupts.WINDBGRM.IS_LOADED) {
/**
* It looks like IFSHLP.SYS issues a preliminary INT 0x68 before Windows 95 gets rolling,
* and the Windows Debugger will not have had a chance to load yet, so we need to ignore
* that call. We detect IFSHLP.SYS by looking for "IFS$" in the caller's code segment,
* where the IFSHLP device driver header is located.
*/
if (cpu.getLong((cpu.segCS.sel << 4) + 0x0A) == 0x24534649) {
this.printf(MESSAGE.DEBUG, "ignoring INT 68 from IFSHLP.SYS\n");
return true;
}
/**
* Ditto for WDEB386 itself, which presumably wants to avoid loading on top of itself.
* The offset of the "WDEB" signature is at 0x82 in the Windows 3.1 version (3.10.46 1/16/92),
* and at 0x5F in the Windows 95 version.
*/
if (cpu.getLong((cpu.segCS.sel << 4) + 0x82) == 0x42454457 ||
cpu.getLong((cpu.segCS.sel << 4) + 0x5F) == 0x42454457) {
this.printf(MESSAGE.DEBUG, "ignoring INT 68 from WDEB386.EXE\n");
return true;
}
/**
* We're only going to respond to this function if no one else did, in which case, we'll set
* fWinDbgRM to true and handle additional notifications.
*/
cpu.addIntReturn(addr, function(dbg) {
return function onInt68Return(nLevel) {
if ((cpu.regEAX & 0xffff) != Interrupts.WINDBGRM.LOADED) {
cpu.regEAX = (cpu.regEAX & ~0xffff) | Interrupts.WINDBGRM.LOADED;
dbg.printf(MESSAGE.DEBUG, "INT 68 handling enabled\n");
/**
* If we turn on INT 0x68 handling, we must also turn on INT 0x41 handling,
* because Windows assumes that the latter handler exists whenever the former does.
*/
dbg.fWinDbg = dbg.fWinDbgRM = true;
} else {
dbg.printf(MESSAGE.DEBUG, "INT 68 monitoring enabled\n");
dbg.fWinDbgRM = false;
}
};
}(this));
}
return true;
}
/**
* NOTE: If this.fWinDbgRM is true, then all cases should return false, because we're taking full
* responsibility for all requests (don't assume there's valid interrupt handler inside the machine).
*/
switch(AH) {
case Interrupts.WINDBGRM.IS_LOADED: // 0x43
if (this.fWinDbgRM) {
cpu.regEAX = (cpu.regEAX & ~0xffff) | Interrupts.WINDBGRM.LOADED;
}
break;
case Interrupts.WINDBGRM.PREP_PMODE: // 0x44
if (this.fWinDbgRM) {
/**
* Use our fancy new "call break" mechanism to obtain a special address that will
* trap all calls, routing control to the specified function (callWindowsDebuggerPMInit).
*/
let a = cpu.segCS.addCallBreak(this.callWindowsDebuggerPMInit.bind(this));
if (a) {
cpu.regEDI = a[0]; // ES:EDI receives the "call break" address
cpu.setES(a[1]);
}
}
break;
case Interrupts.WINDBGRM.FREESEG: // 0x48
this.removeSegmentInfo(BX, this.fWinDbg);
break;
case Interrupts.WINDBGRM.REMOVESEGS: // 0x4F
/**
* TODO: This probably just signals the end of module loading; nothing is required, but we should
* clean up whatever we can....
*/
break;
case Interrupts.WINDBGRM.LOADSEG: // 0x50
if (AL == 0x20) {
/**
* Real-mode EXE
* CX == paragraph
* ES:DI -> module name
*/
this.addSegmentInfo(this.newAddr(DI, ES), 0, CX, true, this.fWinDbgRM);
}
else if (AL < 0x80) {
/**
* AL == segment type:
* 0x00 code selector
* 0x01 data selector
* 0x10 code segment
* 0x11 data segment
* 0x40 code segment & sel
* 0x41 data segment & sel
* BX == segment #
* CX == actual segment/selector
* DX == actual selector (if 0x40 or 0x41)
* ES:DI -> module name
*/
this.addSegmentInfo(this.newAddr(DI, ES), BX+1, (AL & 0x40)? DX : CX, !(AL & 0x1), this.fWinDbgRM);
}
else {
/**
* AL == segment type:
* 0x80 device driver code seg
* 0x81 device driver data seg
* ES:DI -> D386_Device_Params structure (see addSectionInfo() for details)
*/
this.addSectionInfo(this.newAddr(DI, ES), !(AL & 0x1), this.fWinDbgRM);
}
if (this.fWinDbgRM) {
cpu.regEAX = (cpu.regEAX & ~0xff) | 0x01;
}
break;
default:
if (this.fWinDbgRM) {
this.printf(MESSAGE.DEBUG, "INT 68: AH=%02X (unhandled)\n", AH);
}
break;
}
return !this.fWinDbgRM;
}
/**
* callWindowsDebuggerPMInit()
*
* This intercepts calls to the Windows Debugger "PMInit" interface; eg:
*
* AL = function code
*
* 0 - initialize IDT
* ES:EDI points to protected mode IDT
*
* 1 - initialize page checking
* BX = physical selector
* ECX = linear bias
*
* 2 - specify that debug queries are supported
*
* 3 - initialize spare PTE
* EBX = linear address of spare PTE
* EDX = linear address the PTE represents
*
* 4 - set Enter/Exit VMM routine address
* EBX = Enter VMM routine address
* ECX = Exit VMM routine address
* EDX = $_Debug_Out_Service address
* ESI = $_Trace_Out_Service address
* The VMM enter/exit routines must return with a retfd
*
* 5 - get debugger size/physical address
* returns: AL = 0 (don't call AL = 1)
* ECX = size in bytes
* ESI = starting physical code/data address
*
* 6 - set debugger base/initialize spare PTE
* EBX = linear address of spare PTE
* EDX = linear address the PTE represents
* ESI = starting linear address of debug code/data
*
* 7 - enable memory context functions
*
* @this {Debuggerx86}
* @returns {boolean} (must always return false to skip the call, because the call is using a CALLBREAK address)
*/
callWindowsDebuggerPMInit()
{
let cpu = this.cpu;
let AL = cpu.regEAX & 0xff;
if (MAXDEBUG) this.printf("INT 68 callback: AL=%02X\n", AL);
if (AL == 5) {
cpu.regECX = cpu.regESI = 0; // our in-machine debugger footprint is zero
cpu.regEAX = (cpu.regEAX & ~0xff) | 0x01; // TODO: Returning a "don't call" response sounds good, but what does it REALLY mean?
}
return false;
}
/**
* setBinding(sHTMLType, sBinding, control, sValue)
*
* @this {Debuggerx86}
* @param {string} sHTMLType is the type of the HTML control (eg, "button", "list", "text", "submit", "textarea", "canvas")
* @param {string} sBinding is the value of the 'binding' parameter stored in the HTML control's "data-value" attribute (eg, "debugInput")
* @param {HTMLElement} control is the HTML control DOM object (eg, HTMLButtonElement)
* @param {string} [sValue] optional data value
* @returns {boolean} (true if binding was successful, false if unrecognized binding request)
*/
setBinding(sHTMLType, sBinding, control, sValue)
{
let dbg = this;
switch (sBinding) {
case "debugInput":
this.bindings[sBinding] = control;
this.controlDebug = /** @type {HTMLInputElement} */ (control);
/**
* For halted machines, this is fine, but for auto-start machines, it can be annoying.
*
* controlInput.focus();
*/
control.onkeydown = function onKeyDownDebugInput(event) {
let sLine;
if (event.keyCode == Keys.KEYCODE.CR) {
sLine = dbg.controlDebug.value;
dbg.controlDebug.value = "";
dbg.doCommands(sLine, true);
}
else if (event.keyCode == Keys.KEYCODE.ESC) {
dbg.controlDebug.value = sLine = "";
}
else {
if (event.keyCode == Keys.KEYCODE.UP) {
sLine = dbg.getPrevCommand();
}
else if (event.keyCode == Keys.KEYCODE.DOWN) {
sLine = dbg.getNextCommand();
}
if (sLine != null) {
let cch = sLine.length;
dbg.controlDebug.value = sLine;
dbg.controlDebug.setSelectionRange(cch, cch);
}
}
if (sLine != null && event.preventDefault) event.preventDefault();
};
return true;
case "debugEnter":
this.bindings[sBinding] = control;
WebLib.onClickRepeat(
control,
500, 100,
function onClickDebugEnter(fRepeat) {
if (dbg.controlDebug) {
let sCommands = dbg.controlDebug.value;
dbg.controlDebug.value = "";
dbg.doCommands(sCommands, true);
return true;
}
if (DEBUG) dbg.printf(MESSAGE.LOG, "no debugger input buffer\n");
return false;
}
);
return true;
case "step":
this.bindings[sBinding] = control;
WebLib.onClickRepeat(
control,
500, 100,
function onClickStep(fRepeat) {
let fCompleted = false;
if (!dbg.isBusy(true)) {
dbg.setBusy(true);
fCompleted = dbg.stepCPU(fRepeat? 1 : 0);
dbg.setBusy(false);
}
return fCompleted;
}
);
return true;
default:
break;
}
return false;
}
/**
* updateFocus()
*
* @this {Debuggerx86}
*/
updateFocus()
{
if (this.controlDebug) this.controlDebug.focus();
}
/**
* getCPUMode()
*
* @this {Debuggerx86}
* @returns {boolean} (true if protected mode, false if not)
*/
getCPUMode()
{
return !!(this.cpu && (this.cpu.regCR0 & X86.CR0.MSW.PE) && !(this.cpu.regPS & X86.PS.VM));
}
/**
* getAddressType()
*
* @this {Debuggerx86}
* @returns {number}
*/
getAddressType()
{
return this.getCPUMode()? Debuggerx86.ADDRTYPE.PROT : Debuggerx86.ADDRTYPE.REAL;
}
/**
* getSegment(sel, type)
*
* If the selector matches that of any of the CPU segment registers, then return the CPU's segment
* register, instead of using our own segDebugger segment register. This makes it possible for us to
* see what the CPU is seeing at certain critical junctures, such as after an LMSW instruction has
* switched the processor from real to protected mode. Actually loading the selector from the GDT/LDT
* should be done only as a last resort.
*
* @this {Debuggerx86}
* @param {number|undefined} sel
* @param {number} [type] (defaults to getAddressType())
* @returns {Segx86|null} (seg)
*/
getSegment(sel, type)
{
let typeDefault = this.getAddressType();