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/*++
Copyright (c) 1992 Microsoft Corporation
Module Name:
xmem.c
Abstract:
This module contains routines for allocating and freeing "extended" memory.
The memory is allocated directly from NT.
Author:
Dave Hastings (daveh) 12-Dec-1992
Notes:
Moved from dpmi32\i386
Revision History:
09-Feb-1994 (daveh)
Modified to be the common front end for the memory allocation. Calls
processor specific code to do actual allocation
--*/
#include "precomp.h"
#pragma hdrstop
#include "softpc.h"
#include <malloc.h>
//
// Xmem structure
//
typedef struct _Xmem {
PVOID Address;
ULONG Length;
struct _Xmem * Prev;
struct _Xmem * Next;
WORD Owner;
} XMEM_BLOCK, *PXMEM_BLOCK;
XMEM_BLOCK XmemHead = { NULL, 0, &XmemHead, &XmemHead, 0};
#define DELETE_BLOCK(BLK) (BLK->Prev)->Next = BLK->Next;\
(BLK->Next)->Prev = BLK->Prev
#define INSERT_BLOCK(BLK) BLK->Next = XmemHead.Next; BLK->Prev= XmemHead.Next->Prev;\
(XmemHead.Next)->Prev = BLK; XmemHead.Next = BLK
VOID
DpmiAllocateXmem(
VOID
)
/*++
Routine Description:
This routine allocates a block of "extended" memory from NT. The
blocks allocated this way will be 64K aligned (for now). The address
of the block is returned to the segmented app in bx:cx
Arguments:
None.
Return Value:
None.
--*/
{
ULONG BlockAddress, BlockSize;
NTSTATUS Status;
PXMEM_BLOCK XmemBlock;
//
// Get a block of memory from NT (any base address)
//
BlockSize = ((ULONG)getBX() << 16) | getCX();
BlockAddress = 0;
Status = DpmiAllocateVirtualMemory(
(PVOID)&BlockAddress,
&BlockSize
);
if (!NT_SUCCESS(Status)) {
setCF(1);
#if DBG
OutputDebugString("DPMI: DpmiAllocateXmem failed to get memory block\n");
#endif
return;
}
XmemBlock = malloc(sizeof(XMEM_BLOCK));
if (!XmemBlock) {
setCF(1);
DpmiFreeVirtualMemory(
(PVOID)&BlockAddress,
&BlockSize
);
return;
}
XmemBlock->Address = (PVOID)BlockAddress;
XmemBlock->Length = BlockSize;
XmemBlock->Owner = getDX();
INSERT_BLOCK(XmemBlock);
//
// Return the information about the block
//
setBX((USHORT)(BlockAddress >> 16));
setCX((USHORT)(BlockAddress & 0x0000FFFF));
//
// Use xmem block addresss as handle
//
setSI((USHORT)((ULONG)XmemBlock >> 16));
setDI((USHORT)((ULONG)XmemBlock & 0x0000FFFF));
setCF(0);
}
VOID
DpmiFreeXmem(
VOID
)
/*++
Routine Description:
This routine frees a block of "extended" memory from NT.
Arguments:
None.
Return Value:
None.
--*/
{
PXMEM_BLOCK XmemBlock;
NTSTATUS Status;
PVOID BlockAddress;
ULONG BlockSize;
XmemBlock = (PVOID)(((ULONG)getSI() << 16) | getDI());
BlockAddress = XmemBlock->Address;
BlockSize = XmemBlock->Length;
Status = DpmiFreeVirtualMemory(
&BlockAddress,
&BlockSize
);
if (!NT_SUCCESS(Status)) {
setCF(1);
#if DBG
OutputDebugString("DPMI: DpmiFreeXmem failed to free block\n");
#endif
return;
}
DELETE_BLOCK(XmemBlock);
free(XmemBlock);
setCF(0);
return;
}
VOID
DpmiReallocateXmem(
VOID
)
/*++
Routine Description:
This routine resizes a block of "extended memory". If the change in size
is less than 4K, no change is made.
Arguments:
None.
Return Value:
None.
--*/
{
PXMEM_BLOCK OldBlock;
ULONG BlockAddress, NewSize;
NTSTATUS Status;
OldBlock = (PVOID)(((ULONG)getSI() << 16) | getDI());
NewSize = (((ULONG)getBX() << 16) | getCX());
BlockAddress = 0;
Status = DpmiReallocateVirtualMemory(
OldBlock->Address,
OldBlock->Length,
(PVOID)&BlockAddress,
&NewSize
);
if (!NT_SUCCESS(Status)) {
setCF(1);
#if DBG
OutputDebugString("DPMI: DpmiAllocateXmem failed to get memory block\n");
#endif
return;
}
OldBlock->Address = (PVOID)BlockAddress;
OldBlock->Length = NewSize;
//
// Return the information about the block
//
setBX((USHORT)(BlockAddress >> 16));
setCX((USHORT)(BlockAddress & 0x0000FFFF));
setCF(0);
}
VOID
DpmiFreeAppXmem(
VOID
)
/*++
Routine Description:
This routine frees Xmem allocated for the application
Arguments:
Client DX = client PSP selector
Return Value:
TRUE if everything goes fine.
FALSE if unable to release the memory
--*/
{
PXMEM_BLOCK p1, p2;
NTSTATUS Status;
PVOID BlockAddress;
ULONG BlockSize;
WORD selClientPSP;
p1 = XmemHead.Next;
selClientPSP = getDX();
while(p1 != &XmemHead) {
if (p1->Owner == selClientPSP) {
BlockAddress = p1->Address;
BlockSize = p1->Length;
Status = DpmiFreeVirtualMemory(
&BlockAddress,
&BlockSize
);
if (!NT_SUCCESS(Status)) {
#if DBG
OutputDebugString("DPMI: DpmiFreeXmem failed to free block\n");
#endif
return;
}
p2 = p1->Next;
DELETE_BLOCK(p1);
free(p1);
p1 = p2;
continue;
}
p1 = p1->Next;
}
return;
}
VOID
DpmiFreeAllXmem(
VOID
)
/*++
Routine Description:
This function frees all allocated xmem.
Arguments:
none
Return Value:
None.
--*/
{
PXMEM_BLOCK p1, p2;
NTSTATUS Status;
PVOID BlockAddress;
ULONG BlockSize;
p1 = XmemHead.Next;
while(p1 != &XmemHead) {
BlockAddress = p1->Address;
BlockSize = p1->Length;
Status = DpmiFreeVirtualMemory(
&BlockAddress,
&BlockSize
);
if (!NT_SUCCESS(Status)) {
#if DBG
OutputDebugString("DPMI: DpmiFreeXmem failed to free block\n");
#endif
return;
}
p2 = p1->Next;
DELETE_BLOCK(p1);
free(p1);
p1 = p2;
}
}
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