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Assorted tweaks for the DeskPro 386 ROM

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This commit is contained in:
Jeff Parsons 2015-03-26 12:13:16 -07:00 • committed by jeffpar
commit 0cbae3ea11
6 changed files with 75 additions and 12 deletions
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20
modules/pcjs/lib/x86func.js
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@ -1393,10 +1393,15 @@ X86.fnRCLd = function RCLd(dst, src)
{
var result = dst;
var flagsIn = (DEBUG? this.getPS() : 0);
var shift = src & this.nShiftCountMask;
var shift = src & this.nShiftCountMask; // Yes, this 32-bit-only function could mask with 0x1f directly
if (shift) {
var carry = this.getCarry();
result = (dst << shift) | (carry << (shift - 1)) | (dst >>> (32 - shift));
/*
* JavaScript Alert: much like a post-8086 Intel CPU, JavaScript shift counts are mod 32,
* so "dst >>> 32" is equivalent to "dst >>> 0", which doesn't shift any bits at all. To
* compensate, we shift one bit less than the maximum, and then shift one bit farther.
*/
result = (dst << shift) | (carry << (shift - 1)) | ((dst >>> (32 - shift)) >>> 1);
carry = dst << (shift - 1);
X86.setRotateResult.call(this, result, carry, X86.RESULT.DWORD);
}
@ -1472,10 +1477,15 @@ X86.fnRCRd = function RCRd(dst, src)
{
var result = dst;
var flagsIn = (DEBUG? this.getPS() : 0);
var shift = src & this.nShiftCountMask;
var shift = src & this.nShiftCountMask; // Yes, this 32-bit-only function could mask with 0x1f directly
if (shift) {
var carry = this.getCarry();
result = (dst >>> shift) | (carry << (32 - shift)) | (dst << (33 - shift));
/*
* JavaScript Alert: much like a post-8086 Intel CPU, JavaScript shift counts are mod 32,
* so "dst << 32" is equivalent to "dst << 0", which doesn't shift any bits at all. To
* compensate, we shift one bit less than the maximum, and then shift one bit farther.
*/
result = (dst >>> shift) | (carry << (32 - shift)) | ((dst << (32 - shift)) << 1);
carry = dst << (32 - shift);
X86.setRotateResult.call(this, result, carry, X86.RESULT.DWORD);
}
@ -1507,7 +1517,7 @@ X86.fnRETF = function RETF(n)
*
* TODO: I'm not clear on whether a conforming code segment must also be marked readable, so I'm playing
* it safe and using CODE_CONFORMING instead of CODE_CONFORMING_READABLE. Also, for the record, I've not
* seen this situation occur in OS/2 1.0 yet.
* seen this situation occur yet (eg, in OS/2 1.0).
*/
if ((this.segDS.sel & X86.SEL.MASK) && this.segDS.dpl < this.segCS.cpl && (this.segDS.acc & X86.DESC.ACC.TYPE.CODE_CONFORMING) != X86.DESC.ACC.TYPE.CODE_CONFORMING) {
this.assert(false); // I'm not asserting this is bad, I just want to see it in action