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80386 CPU detection fix

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This commit is contained in:
Jeff Parsons 2015-07-14 16:32:41 -07:00
commit 75d8e1e193
24 changed files with 123 additions and 60 deletions
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23
modules/pcjs/lib/x86cpu.js
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@ -1014,6 +1014,7 @@ X86CPU.prototype.initProcessor = function()
{
this.PS_SET = X86.PS_SET_8086;
this.PS_DIRECT = X86.PS_DIRECT_8086;
this.PS_CLEAR_RM = X86.PS.IOPL.MASK | X86.PS.NT;
this.OPFLAG_NOINTR_8086 = X86.OPFLAG.NOINTR;
this.nShiftCountMask = 0xff; // on an 8086/8088, all shift counts are used as-is
@ -1080,6 +1081,13 @@ X86CPU.prototype.initProcessor = function()
if (I386 && this.model >= X86.MODEL_80386) {
var bOpcode;
/*
* TODO: Determine if the Nested Task (PS.NT) flag should really be cleared in real-mode on an 80386
* (we already know based on the OS/2 CPU test discussed in setPS() that it can't be set in real-mode
* on an 80286); for now, we assume that it should remain clear on all CPUs, to avoid any unexpected
* nested-task weirdness in real-mode.
*/
this.PS_CLEAR_RM = X86.PS.NT;
this.aOps[X86.OPCODE.FS] = X86.opFS; // 0x64
this.aOps[X86.OPCODE.GS] = X86.opGS; // 0x65
this.aOps[X86.OPCODE.OS] = X86.opOS; // 0x66
@ -2680,14 +2688,17 @@ X86CPU.prototype.setPS = function(regPS, cpl)
/*
* OS/2 1.0 discriminates between an 80286 and an 80386 based on whether an IRET in real-mode that
* pops 0xF000 into the flags is able to set *any* of flag bits 12-15: if it can, then OS/2 declares
* the CPU an 80386. Therefore, in real-mode, we must zero all incoming bits 12-15.
* the CPU an 80386.
*
* This has the added benefit of relieving us from zeroing the effective IOPL (this.nIOPL) whenever
* we're in real-mode, since we're zeroing the incoming IOPL bits up front now.
* So, if the CPU is an 80286, we zero incoming bits 12-14 in real-mode (bit 15 is never allowed to
* be modified, so there's no need to mask it). And if the CPU is an 80386, we zero only bit 14 (PS.NT),
* allowing the IOPL bits to change; however, that should not affect any real-mode operations, since
* segCS.cpl will always be zero, making the IOPL setting irrelevant.
*
* It's still an open question whether an 80386 should also clear the Nested Task (PS.NT) flag in
* real-mode; if not, then initProcessor() should set PS_CLEAR_RM to zero.
*/
if (!(this.regCR0 & X86.CR0.MSW.PE)) {
regPS &= ~(X86.PS.IOPL.MASK | X86.PS.NT | X86.PS.BIT15);
}
if (!(this.regCR0 & X86.CR0.MSW.PE)) regPS &= ~this.PS_CLEAR_RM;
/*
* There are some cases (eg, an IRET returning to a less privileged code segment) where the CPL