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Fix an inconsistency in Debugger address parsing (problems mixing segment and physical addresses)

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This commit is contained in:
Jeff Parsons 2014-10-02 10:48:41 -07:00 • committed by jeffpar
commit a474ddfa74
3 changed files with 52 additions and 43 deletions
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26
my_modules/pcjs-client/lib/debugger.js
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@ -87,10 +87,10 @@ function Debugger(parmsDbg)
* update aAddrNextData and aAddrNextCode, respectively, when they're done.
*
* The format of all aAddr variables is [off, seg, addr], where seg:off is the segmented
* address and addr is the corresponding physical address. For some segmented addresses
* (eg, breakpoint addresses), we pre-compute the physical address and save that in aAddr[2],
* so that the breakpoint will still operate as intended even if the mode changes later
* (eg, from real-mode to protected-mode).
* address and addr is the corresponding physical address (if known). For certain segmented
* addresses (eg, breakpoint addresses), we pre-compute the physical address and save that
* in aAddr[2], 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 aAddr[3] to true, so that they can be
* automatically cleared when they're hit.
@ -2112,7 +2112,9 @@ if (DEBUGGER) {
}
if (aAddr[1] != null) {
aAddr[0] += inc;
// TODO: Shouldn't we be using the segment (aAddr[1]) limit instead of 0xffff?
/*
* TODO: Shouldn't we be using the segment (aAddr[1]) limit instead of 0xffff?
*/
if (aAddr[0] != (aAddr[0] & 0xffff)) {
aAddr[0] = aAddr[0] & 0xffff;
aAddr[2] = null;
@ -2318,6 +2320,7 @@ if (DEBUGGER) {
* or history data (see checkInstruction), since we might not actually execute the current instruction.
*/
var fBreak = false;
/*
* Map addresses in the top 64Kb (at the top of the 16Mb range) to the top of the 1Mb range.
*
@ -2326,6 +2329,7 @@ if (DEBUGGER) {
* in the top 16Mb, yet after the first inter-segment JMP, you will be running in the first 1Mb.
*/
if ((addr & 0xFF0000) == 0xFF0000) addr &= 0x0FFFFF;
for (var i = 1; i < aBreak.length; i++) {
var aAddrBreak = aBreak[i];
if (addr == this.getAddr(aAddrBreak)) {
@ -2731,9 +2735,8 @@ if (DEBUGGER) {
* addresses. If/when we add support for processors with page tables, we will likely adopt the same
* convention for linear addresses and provide a different syntax (eg, "%%") physical memory references.
*
* Address evaluation and validation (eg, range checks) are no longer performed at this stage, which
* is why aAddr variables no longer contain an addr element; computing addr is now performed as-needed
* by getAddr(), which will return a negative result (-1) for invalid segments, out-of-range offsets,
* Address evaluation and validation (eg, range checks) are no longer performed at this stage. That's
* done later, by getAddr(), which returns a negative result (-1) for invalid segments, out-of-range offsets,
* etc. The Debugger's low-level get/set memory functions verify all getAddr() results, but even if an
* invalid address is passed through to the Bus memory interfaces, the address will simply be masked with
* Bus.addrLimit; in the case of -1, that will generally refer to the last byte of physical memory.
@ -2762,7 +2765,7 @@ if (DEBUGGER) {
var iColon = sAddr.indexOf(":");
if (iColon < 0) {
if (addr == null) {
if (seg != null) {
off = this.parseValue(sAddr);
} else {
addr = this.parseValue(sAddr);
@ -2771,6 +2774,7 @@ if (DEBUGGER) {
else {
seg = this.parseValue(sAddr.substring(0, iColon));
off = this.parseValue(sAddr.substring(iColon + 1));
addr = null;
}
}
return [off, seg, addr];
@ -4020,8 +4024,8 @@ if (DEBUGGER) {
this.aAddrNextCode = this.newAddr(this.cpu.regIP, this.cpu.segCS.sel);
break;
/*
* I used to alias "PC" to "IP", until I discovered that early (perhaps even ALL?) versions of DEBUG
* treat "PC" as an alias for the 16-bit flags register. TODO: Add support for "PC" that matches DEBUG.
* I used to alias "PC" to "IP", until I discovered that early (perhaps ALL) versions of
* DEBUG.COM treat "PC" as an alias for the 16-bit flags register. TODO: Add support for "PC".
*/
case "IP":
fIns = true;