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Changed Debugger and diagnostic functions to call probeAddr() to safely probe linear addresses

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This commit is contained in:
Jeff Parsons 2015-05-08 12:22:12 -07:00 • committed by jeffpar
commit ab0399064e
4 changed files with 27 additions and 7 deletions
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2
modules/pcjs/bin/romtests.json
View file

@ -78,7 +78,7 @@
"debugger": {
"id": "pc386.debugger",
"name": "",
"commands": "bp 0010:829B;g",
"commands": "",
"messages": ""
}
}

11
modules/pcjs/lib/debugger.js
View file

@ -1460,7 +1460,7 @@ if (DEBUGGER) {
var addr = this.getAddr(dbgAddr, false, 1);
if (addr !== X86.ADDR_INVALID) {
this.nSuppress++;
b = this.cpu.getByte(addr);
b = this.cpu.probeAddr(addr) | 0;
this.nSuppress--;
if (inc) this.incAddr(dbgAddr, inc);
}
@ -1497,7 +1497,7 @@ if (DEBUGGER) {
var addr = this.getAddr(dbgAddr, false, 2);
if (addr !== X86.ADDR_INVALID) {
this.nSuppress++;
w = this.cpu.getShort(addr);
w = this.cpu.probeAddr(addr) | (this.cpu.probeAddr(addr + 1) << 8);
this.nSuppress--;
if (inc) this.incAddr(dbgAddr, inc);
}
@ -1518,7 +1518,7 @@ if (DEBUGGER) {
var addr = this.getAddr(dbgAddr, false, 4);
if (addr !== X86.ADDR_INVALID) {
this.nSuppress++;
l = this.cpu.getLong(addr);
l = this.cpu.probeAddr(addr) | (this.cpu.probeAddr(addr + 1) << 8) | (this.cpu.probeAddr(addr + 2) << 16) | (this.cpu.probeAddr(addr + 3) << 24);
this.nSuppress--;
if (inc) this.incAddr(dbgAddr, inc);
}
@ -1887,7 +1887,8 @@ if (DEBUGGER) {
for (var sField in Debugger.aTSSFields) {
var off = Debugger.aTSSFields[sField];
var ch = (sField.length < 8? ' ' : '');
var w = this.cpu.getShort(seg.base + off);
var addr = seg.base + off;
var w = this.cpu.probeAddr(addr) | (this.cpu.probeAddr(addr + 1) << 8);
if (sDump) sDump += '\n';
sDump += str.toHexWord(off) + " " + sField + ": " + ch + str.toHexWord(w);
}
@ -2686,7 +2687,7 @@ if (DEBUGGER) {
*/
if (nState >= 0 && this.aaOpcodeCounts.length) {
this.cInstructions++;
var bOpcode = this.cpu.getByte(addr);
var bOpcode = this.cpu.probeAddr(addr);
this.aaOpcodeCounts[bOpcode][1]++;
var a = this.aOpcodeHistory[this.iOpcodeHistory];
a[0] = this.cpu.getIP();

18
modules/pcjs/lib/x86cpu.js
View file

@ -2703,6 +2703,24 @@ X86CPU.prototype.setBinding = function(sHTMLType, sBinding, control)
return fBound;
};
/**
* probeAddr(addr)
*
* Used by the Debugger to probe addresses without risk of triggering a page fault, and by internal
* functions, like fnFaultMessage(), that also need to avoid triggering faults, since they're not part
* of standard CPU operation.
*
* @this {X86CPU}
* @param {number} addr is a linear address
* @return {number|null} byte (8-bit) value at that address, or null if invalid
*/
X86CPU.prototype.probeAddr = function(addr)
{
var block = this.aMemBlocks[(addr & this.memMask) >>> this.blockShift];
if (block.type == Memory.TYPE.UNPAGED) return null;
return block.readByteDirect(addr & this.blockLimit, addr);
};
/**
* getByte(addr)
*

3
modules/pcjs/lib/x86func.js
View file

@ -3666,7 +3666,8 @@ X86.fnPageFault = function(addr, fPresent, fWrite)
X86.fnFaultMessage = function(nFault, nError, fHalt)
{
var bitsMessage = Messages.FAULT;
var bOpcode = this.getByte(this.regLIP);
var bOpcode = this.probeAddr(this.regLIP);
/*
* OS/2 1.0 uses an INT3 (0xCC) opcode in conjunction with an invalid IDT to trigger a triple-fault