Category : C++ Source Code
Archive : VMVCPP.ZIP
Filename : VMEMS.C
Output of file : VMEMS.C contained in archive : VMVCPP.ZIP
* vmems.c -
*
* Copyright (c) 1989-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
*
* PRIVATE Functions:
*
* VmInitializeEms:
*
* VmTerminateEms:
*
* FVmAllocateEmsPage:
*
* VmMapInEmsPage:
*
*******************************************************************************/
#pragma title("Virtual Memory Manager")
#pragma subtitle("DOS Expanded memory support")
#include
#include
#include
#include
#include
#include
#include
#if VMFREE
#define cVmPageQueuedEmsMost 8
#else /* !VMFREE */
#define cVmPageQueuedEmsMost 1
#endif /* !VMFREE */
extern char _near _fVmDisableEms = FALSE;
static char _near _fVmUseEms;
static HEMS _near hemsVm;
static unsigned _near _cVmPageHems;
static unsigned _near _cVmPageQueuedEms;
static unsigned _near rgiVmPageQueuedEms[cVmPageQueuedEmsMost];
#if VMFREE
static unsigned _near iVmPageEmsNextFree;
#endif /* VMFREE */
#if VMPROFILE
unsigned long _near _cVmSwapInEms;
unsigned long _near _cVmSwapOutEms;
#endif /* VMPROFILE */
#pragma page()
void PRIVATE __VmInitializeEms(void)
{
VmTracePrintf(("VmInitializeEms\n"));
#if VMPROFILE
_cVmSwapInEms = _cVmSwapOutEms = 0;
#endif
if (_fVmDisableEms ||
!__FEmsCheckInstalled() ||
(__ErrEmsAllocatePages(&hemsVm, 1) != errNoError)
)
{
_fVmUseEms = FALSE;
return;
}
_fVmUseEms = TRUE;
_cVmPageHems = 1;
_cVmPageQueuedEms = 1;
rgiVmPageQueuedEms[0] = 0;
#if VMFREE
iVmPageEmsNextFree = 0xffff;
#endif /* VMFREE */
}
#pragma page()
void PRIVATE __VmTerminateEms(void)
{
VmTracePrintf(("VmTerminateEms\n"));
VmProfilePrintf(("VmProfile:\t_cVmSwapInEms = %lu, _cVmSwapOutEms = %lu\n",
_cVmSwapInEms, _cVmSwapOutEms));
if (_fVmUseEms)
{
__ErrEmsDeallocatePages(hemsVm);
_fVmUseEms = FALSE;
}
}
#pragma page()
void LOCAL __VmFillEmsQueue(void)
{
VmTracePrintf(("VmFillEmsQueue\n"));
Assert(_fVmUseEms && (_cVmPageQueuedEms == 0));
#if VMFREE
if (iVmPageEmsNextFree != 0xffff)
{
ERR err;
move_source_dest emsmove;
/* Insert first free page in queue. */
/* CONSIDER: Should more than one page be added to queue. */
/* CONSIDER: I chose not to because a subsequent set of */
/* CONSIDER: calls to VmFreeEmsPage could result in more */
/* CONSIDER: EMS calls than occur by not doing so. */
rgiVmPageQueuedEms[_cVmPageQueuedEms++] = iVmPageEmsNextFree;
emsmove.cb = sizeof(iVmPageEmsNextFree);
emsmove.fEmsSource = 1;
emsmove.hemsSource = hemsVm;
emsmove.ibSource = 0;
emsmove.iPageSource = iVmPageEmsNextFree;
emsmove.fEmsDest = 0;
emsmove.hemsDest = 0;
emsmove.ibDest = (unsigned) (void _near *) &iVmPageEmsNextFree;
emsmove.segDest = (_segment) &iVmPageEmsNextFree;
err = __ErrEmsMoveMemoryRegion(&emsmove);
Assert(err == errNoError);
}
else
#endif /* VMFREE */
{
if (__ErrEmsReallocatePages(hemsVm, _cVmPageHems + 1) != errNoError)
return;
rgiVmPageQueuedEms[_cVmPageQueuedEms++] = _cVmPageHems++;
VmTracePrintf(("Reallocated EMS Handle. cPage = %04X.\n", _cVmPageHems));
}
}
#pragma page()
int PRIVATE __FVmAllocateEmsPage(PPTE ppte, VPVOID vp)
{
PPTE ppteBase;
unsigned iPage;
PTE pte;
if (!_fVmUseEms)
return(FALSE);
Assert(*ppte == 0);
/* Find the base of this 16K range */
ppteBase = ppte - ((vp & 16383UL) / cbVmPage);
/* EMS is only allocated in 16K blocks. For this allocation to */
/* succeed, the 16K block containing this page must not contain */
/* any pages assigned swap storage in XMS or disk. */
for (iPage = 0; iPage < 16384U / cbVmPage; iPage++)
{
Assert(!(ppteBase[iPage] & fEmsPte));
if (ppteBase[iPage] & (fXmsPte | fDiskPte))
return(FALSE);
}
if (_cVmPageQueuedEms == 0) /* No Queued pages available. */
__VmFillEmsQueue();
if (_cVmPageQueuedEms == 0) /* Queue remains empty. No EMS left. */
return(FALSE);
pte = (rgiVmPageQueuedEms[--_cVmPageQueuedEms] * 16384UL) | fEmsPte;
vp &= ~(VPVOID) (cbVmPage - 1UL); /* Virtual address of base of range */
for (iPage = 0; iPage < 16384U / cbVmPage; iPage++)
{
HPGD hpgd;
/* Remember the assigned swap location in the page tables. */
ppteBase[iPage] |= pte;
/* If this page is resident, the swap location must be updated in */
/* the page descriptor as well or else the page won't be swapped */
/* out to the correct location. */
if ((ppteBase[iPage] & fAllocatedPte) &&
((hpgd = __HpgdSearchCache(vp)) != hpgdNil))
PpgdOfHpgd(hpgd)->pte |= pte;
pte += cbVmPage;
vp += cbVmPage;
}
*ppte |= fAllocatedPte | fUnreferencedPte;
VmTracePrintf(("FVmAllocateEmsPage: SwapLocation = %08lX.\n", *ppte & bitSwapPte));
return(TRUE);
}
#pragma page()
#if VMFREE
void PRIVATE __VmFreeEmsPage(PPTE ppte)
{
PPTE ppteBase;
unsigned iPage;
VmTracePrintf(("VmFreeEmsPage: SwapLocation = %08lX.\n", *ppte & bitSwapPte));
Assert(_fVmUseEms && (*ppte & fEmsPte) && !(*ppte & fAllocatedPte));
/* Find the base of this 16K range */
ppteBase = ppte - ((*ppte & bitSwapPte & 16383UL) / cbVmPage);
/* If any page in this page is allocated, don't free the EMS page. */
for (iPage = 0; iPage < 16384U / cbVmPage; iPage++)
{
Assert(ppteBase[iPage] & fEmsPte);
if (ppteBase[iPage] & fAllocatedPte)
return;
}
iPage = (unsigned) ((*ppte & bitSwapPte) / 16384UL);
if (_cVmPageQueuedEms < cVmPageQueuedEmsMost)
rgiVmPageQueuedEms[_cVmPageQueuedEms++] = iPage;
else
{
ERR err;
move_source_dest emsmove;
emsmove.cb = sizeof(iVmPageEmsNextFree);
emsmove.fEmsDest = 1;
emsmove.hemsDest = hemsVm;
emsmove.ibDest = 0;
emsmove.iPageDest = iPage;
emsmove.fEmsSource = 0;
emsmove.hemsSource = 0;
emsmove.ibSource = (unsigned) (void _near *) &iVmPageEmsNextFree;
emsmove.segSource = (_segment) &iVmPageEmsNextFree;
err = __ErrEmsMoveMemoryRegion(&emsmove);
Assert(err == errNoError);
iVmPageEmsNextFree = iPage;
}
for (iPage = 0; iPage < 16384U / cbVmPage; iPage++)
ppteBase[iPage] = 0;
}
#endif /* VMFREE */
#pragma page()
int PRIVATE __FVmSwapInEmsPage(PTE pte, HPGD hpgd)
{
ERR err;
move_source_dest emsmove;
VmTracePrintf(("VmSwapInEmsPage: pPage = %Fp, SwapLocation = %08lX.\n",
PPageOfHpgd(hpgd), pte & bitSwapPte));
#if VMPROFILE
_cVmSwapInEms++;
#endif
Assert(_fVmUseEms && (pte & fEmsPte));
emsmove.cb = cbVmPage;
emsmove.fEmsSource = 1;
emsmove.hemsSource = hemsVm;
emsmove.ibSource = (unsigned) ((pte & bitSwapPte) & 16383UL);
emsmove.iPageSource = (unsigned) ((pte & bitSwapPte) / 16384UL);
emsmove.fEmsDest = 0;
emsmove.hemsDest = 0;
emsmove.ibDest = 0;
emsmove.segDest = PpgdOfHpgd(hpgd)->segPage;
err = __ErrEmsMoveMemoryRegion(&emsmove);
Assert(err == errNoError);
return(err == errNoError);
}
#pragma page()
int PRIVATE __FVmSwapOutEmsPage(PTE pte, HPGD hpgd)
{
ERR err;
move_source_dest emsmove;
VmTracePrintf(("VmSwapOutEmsPage: vp = %08lX, pPage = %Fp, SwapLocation = %08lX.\n",
PpgdOfHpgd(hpgd)->vp, PPageOfHpgd(hpgd), pte & bitSwapPte));
#if VMPROFILE
_cVmSwapOutEms++;
#endif
Assert(_fVmUseEms && (pte & fEmsPte));
emsmove.cb = cbVmPage;
emsmove.fEmsSource = 0;
emsmove.hemsSource = 0;
emsmove.ibSource = 0;
emsmove.segSource = PpgdOfHpgd(hpgd)->segPage;
emsmove.fEmsDest = 1;
emsmove.hemsDest = hemsVm;
emsmove.ibDest = (unsigned) ((pte & bitSwapPte) & 16383U);
emsmove.iPageDest = (unsigned) ((pte & bitSwapPte) / 16384UL);
err = __ErrEmsMoveMemoryRegion(&emsmove);
Assert(err == errNoError);
return(err == errNoError);
}
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