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2689 lines
83 KiB
2689 lines
83 KiB
PAGE ,132
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TITLE DXMMGR - Dos Extender Memory Management Routines
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; Copyright (c) Microsoft Corporation 1988-1991. All Rights Reserved.
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;****************************************************************
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;* *
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;* DXMMGR.ASM - Dos Extender Memory Manager *
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;* *
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;****************************************************************
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;* *
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;* Module Description: *
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;* *
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;* This module contains routines for maintaining a dynamic *
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;* memory heap in extended memory for use in the Dos Extender. *
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;* *
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;* There are two kinds of objects in the memory heap. There *
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;* are block headers and data blocks. The block headers are *
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;* each 16 bytes long, and are organized in a doubly linked *
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;* list. There is a segment descriptor in the global *
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;* descriptor table for each block header, with each header *
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;* containing the selectors for the next and previous block *
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;* to form the list. Block headers can either control a free *
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;* block or they can control a data block. In either case, *
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;* the block immediately follows the header in memory, and *
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;* the header contains a field that gives its size. Free *
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;* blocks do not have a descriptor in the global descriptor *
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;* table, but in use data blocks do. In the case where the *
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;* in use data block is larger than 64k, there will be a *
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;* contiguous range of selectors for the block. The block *
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;* header contains a field giving the initial selector for *
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;* the data block for in use blocks. *
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;* *
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;* A special type of free block serve as sentinels. They mark *
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;* start and end of each physical block of memory available to *
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;* the memory manager. They are identified by the reserved *
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;* value of 0FFFE (start sentinel) and 0FFFF (end sentinel) in *
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;* the selBlkOwner field. Unlike other blocks, they may not be *
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;* moved without appeal to some higher level of memory *
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;* allocation. *
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;* *
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;* Except for a pair of sentinels, a pair of blocks are *
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;* contiguous in memory if and only if their headers are *
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;* adjacent in the header chain. *
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;* *
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;* The blocks at the start and end of the header chain are *
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;* sentinals. Their selectors are stored in global variables. *
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;* The start and end of the block header chain are identified *
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;* by NULL (0) pointers in the Next and Previous pointer fields*
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;* respectively. *
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;* *
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;****************************************************************
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;* Naming Conventions Used: *
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;* *
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;* The following hungarian prefixes are used in this module: *
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;* lp - far pointer (selector:offset) *
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;* bp - linear byte pointer (32 bit byte offset from *
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;* the beginning of memory) *
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;* p - near pointer (16 bit offset) *
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;* sel - protected mode segment selector *
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;* seg - real mode paragraph address *
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;* cb - count of bytes *
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;* id - generic byte that contains an ID code *
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;* hmem - handle to XMS extended memory block *
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;* *
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;****************************************************************
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;* Revision History: *
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;* *
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;* 11/28/90 amitc IntLowHeap allocates memory from Switcher *
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;* if it can. *
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;* *
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;* 08/08/90 earleh DOSX and client privilege ring determined *
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;* by equate in pmdefs.inc *
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;* 05/09/90 jimmat Started VCPI changes. *
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;* 05/09/90 jimmat Incorporated bug fix from CodeView folks, *
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;* changes marked with [01] *
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;* 06/23/89 jimmat: Added init of variable with heap handle *
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;* 04/17/89 jimmat: Added routines for special low memory *
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;* heap for use by network mapping *
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;* 03/28/89 jimmat: Incorporated bug fixes from GeneA *
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;* 02/10/89 (GeneA): changed Dos Extender from small model to *
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;* medium model *
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;* 12/07/88 (GeneA): moved SetupHimemDriver to dxinit.asm *
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;* 08/30/88 (GeneA): created *
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;* *
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;****************************************************************
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.286p
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; -------------------------------------------------------
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; INCLUDE FILE DEFINITIONS
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; -------------------------------------------------------
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include gendefs.inc
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include segdefs.inc
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include pmdefs.inc
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include dpmi.inc
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; -------------------------------------------------------
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; GENERAL SYMBOL DEFINITIONS
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; -------------------------------------------------------
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; -------------------------------------------------------
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; EXTERNAL SYMBOL DEFINITIONS
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; -------------------------------------------------------
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extrn XMScontrol:FAR
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pmxmssvc macro fcn
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ifnb <fcn>
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mov ah, fcn
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endif
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call XMScontrol
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endm
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extrn FreeSelector:NEAR
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extrn FreeSelectorBlock:NEAR
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extrn AllocateSelector:NEAR
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extrn AllocateSelectorBlock:NEAR
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extrn GetSegmentAddress:NEAR
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extrn SetSegmentAddress:NEAR
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extrn DupSegmentDscr:NEAR
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externFP NSetSegmentDscr
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extrn RemoveFreeDescriptor:NEAR
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extrn EnterProtectedMode:NEAR
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extrn EnterRealMode:NEAR
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extrn MoveMemBlock:NEAR
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ifdef WOW_x86
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externNP NSetSegmentAccess
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externNP NSetSegmentBase
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externNP NSetSegmentLimit
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endif
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DXDATA segment
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extrn selPSPChild:WORD
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extrn selGDT:WORD
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extrn bpGDT:FWORD
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ifdef WOW_x86
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extrn FastBop:fword
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endif
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DXDATA ends
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; -------------------------------------------------------
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; DATA SEGMENT DECLARATIONS
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; -------------------------------------------------------
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DXDATA segment
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; Minimum xmem allocation in K
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; Note: This value MUST be a power of 2!!!
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; Note: We will allocate a smaller block if only smaller blocks
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; are available from xms
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XMEM_MIN_ALLOC equ 256
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extrn lpfnXmsFunc:DWORD
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;
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; These variables control access to the extended memory heap.
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public cKbInitialHeapSize
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cKbInitialHeapSize dw -1 ; Optional specification for first block
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; of extended memory in KB.
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public dsegCurrent
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dsegCurrent dw 0 ; Paragraph count if the current block comes from DOS
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public hmemHeap
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hmemHeap dw ? ;XMS memory manager handle to the memory
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; block containing the heap
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bpHeapStart dd ? ;byte address of start of heap
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; (points to block header of first heap block)
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bpHeapEnd dd ? ;byte address of end of heap
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; (points to block header of last heap block)
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cbHeapMove dd ? ;number of bytes by which a subheap moved
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public cbHeapSize,selLowHeapStart,selHiHeapStart,selHeapStart
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cbHeapSize dd ? ;number of bytes in the heap
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selHeapStart dw ? ;selector for the sentinel block at the
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; start of the heap list
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bpCurTop dd 0 ;current top of compacted heap
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; (used during heap compaction)
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cbHeapBlkMax dd ? ;size of largest free block seen while
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; searching the heap
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cbHeapFreeSpace dd ? ;total free space in the heap
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selHiHeapStart dw ? ;selector for the sentinel block at the start
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; of the higm memory heap
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selLowHeapStart dw ? ;selector for the sentinel block at the start
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; of the special low heap
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segLowHeap dw ? ;segment address of low memory heap
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selLowHeapEnd dw ? ;selector for the sentinel block at the end
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; of the special low heap
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fDosErr db ?
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public hmem_XMS_Table,hmem_XMS_Count
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hmem_XMS_Table dw CXMSBLOCKSDX DUP(0)
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hmem_XMS_Count dw 0
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public NoAsyncSwitching
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NoAsyncSwitching db 0 ;0=> async switching allowed
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public LowMemAllocFn,LowMemFreeFn
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LowMemAllocFn dd 0
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LowMemFreeFn dd 0
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DXDATA ends
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; -------------------------------------------------------
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; MISCELLANEOUS DATA STRUCTURE DECLARATIONS
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; -------------------------------------------------------
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; ****** also in dxvcpi.asm ******
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.ERRE CB_MEMHDR EQ 10h ;size of memory block header
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; ****** also in dxvcpi.asm ******
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; This segment declaration describes the format of the memory
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; block header at the beginning of each object in the heap.
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MEMHDR segment at 0 ;Analogous to MS-DOS arenas
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fBlkStatus db ? ;Status bits about the arena block
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cselBlkData db ? ;number of selectors used by the data block
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; that this arena header controls
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selBlkData dw ? ;initial selector for the data block that this
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; arena header controls.
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; (if the block is >64k, this is the first of the
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; range of selectors assigned to the block)
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selBlkOwner dw ? ;PSP selector of owner. 0 if free.
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;
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; !!!!! There is code in ModifyXmemBlock which depends on the previous
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; !!!!! four fields (and only those) being at lower addresses than selBlkHdr.
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;
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selBlkHdr dw ? ;the selector of the block header. This points
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; back at itself, so that we can find the selector
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; to the header from its address
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selBlkNext dw ? ; next block header selector
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selBlkPrev dw ? ; previous block header selector
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cbBlkLen LABEL DWORD ; Block size in bytes
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hBlockHandle dw ? ; The handle returned by DOS or HIMEM
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dsegBlock dw ? ; 0 => HIMEM ELSE DOS paragraph count
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MEMHDR ends
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; -------------------------------------------------------
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subttl Initialization Routines
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page
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DXPMCODE segment
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assume cs:DXPMCODE
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; -------------------------------------------------------
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; INITIALIZATION ROUTINES
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; -------------------------------------------------------
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;
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; InitLowHeap -- Allocate and initialize the special low
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; memory heap for use by network buffers
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; and the like.
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;
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; Input: AX - number of K bytes of LOW heap needed
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; (assumed to be < 1 Meg)
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; Output: none
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; Errors: CY set if error occurs
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; Uses: All registers preserved
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;
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; Note: This routine must be called in protected mode
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; and it assumes that interrupts should be enabled
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; while it runs.
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assume ds:DGROUP,es:DGROUP,ss:NOTHING
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public InitLowHeap
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InitLowHeap proc near
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ret
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InitLowHeap endp
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; -------------------------------------------------------
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; AddToXmemHeap -- This routine will add a block of memory
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; to the extended memory heap. It creates the sentinel header
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; blocks and a header block for a free object containing
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; the new memory.
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;
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; Input: CX - Least significant part of minimum block length required
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; DX - Most significant part of minimum block length required
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; Output: None
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; Errors: None
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; Uses:
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; NOTES: This routine must be called in protected mode.
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; With XMS-only providing memory, all XMS memory is allocated
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; the first time this routine is called.
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;
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; If VCPI is active, and VCPI memory is being used, then
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; enough memory is allocated from the server to satisfy
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; the request. The allocation is handled in dxvcpi.asm.
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;
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assume ds:DGROUP,es:NOTHING,ss:NOTHING
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cProc AddToXmemHeap,<NEAR,PUBLIC>,<ax,bx,cx,dx,si,es>
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cBegin
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;
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; Add to requested size the size of our header overhead
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;
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add cx,3*CB_MEMHDR ; Adjust for header overhead
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adc dx,0
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;
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; Round allocation up to next MIN_ALLOC size by first rounding up to the
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; nearest 1K, then converting to K and rounding
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;
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add cx,1023
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adc dx,0
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shr cx,10
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push dx
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shl dx,6
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or cx,dx ; cx is now size rounded to K
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pop dx
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add cx,XMEM_MIN_ALLOC - 1
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adc dx,0
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and cx,NOT (XMEM_MIN_ALLOC - 1) ; rounded to next higher MIN_ALLOC
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; See How much memory is available from the HIMEM driver
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atxh100:
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pmxmssvc 8 ; query freespace available
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cmp bl,0 ; Test for error
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jnz atxhDone ; No luck - Try DOS
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cmp ax,0
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je atxhDone
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; cmp ax,cx ; is largest block > allocation desired?
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; jb atxh110 ; no, use largest block
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; mov ax,cx ; yes, use desired alloc
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atxh110:
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mov dx,ax ; Load reported size of largest free block
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mov bx,ax ; Calculate number of bytes available
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shl bx,10
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shr ax,6 ; AX:BX = available bytes
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sub bx,3*CB_MEMHDR ; Adjust for header overhead
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sbb ax,0
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mov word ptr cbHeapSize,bx ; Save lower order bytes available
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mov word ptr [cbHeapSize+2],ax ; Save higher order bytes available
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pmxmssvc 9 ; Allocate the largest possible block
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cmp ax,0 ; Check for error
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jz atxhDone ; HIMEM driver speak with forked tongue
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mov hmemHeap,dx ; Save the handle
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pmxmssvc 0Ch ; Lock and query address
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xchg bx,dx
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mov dsegCurrent,0 ; Flag this allocate was not from DOS
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cmp ax,0 ; Test result
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jnz atxh300 ; Rejoin common code
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Trace_Out "AddToXmemHeap: Lock of XMS handle #DX failed."
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jmp atxhDone ; Jump on error
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atxh300:
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call StructureHeap ; Build sentinels and free block
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mov ax,selHeapStart ; Remember the high heap start selector
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mov selHiHeapStart,ax
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; Done allocating memory.
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atxhDone:
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cEnd
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; -------------------------------------------------------
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; InitXmemHeap -- This routine will initialize the
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; extended memory heap.
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;
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; Input:
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; Output:
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; Errors:
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; Uses:
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;
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assume ds:DGROUP,es:DGROUP,ss:NOTHING
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public InitXmemHeap
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InitXmemHeap:
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ret
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IFNDEF WOW_x86
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; -------------------------------------------------------
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; FreeXmemHeap -- This routine gives the xms memory back to
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; the xms driver. The selectors for the heap are not
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; freed. Shortly after we release the heap, the LDT will
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; be reinitialized, and that will free the selectors
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;
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public FreeXmemHeap
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FreeXmemHeap:
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ret ; bugbug
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ENDIF
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; -------------------------------------------------------
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; StructureHeap -- This routine creates the sentinel header
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; blocks and a header block for a free object containing
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; the new memory.
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;
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; Input: BX - Most significant part of heap block address
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; DX - Least significant part of heap block address
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;
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; Output: None
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; Errors: Carry flag set if there was not enough memory available
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; Uses: BX, DX
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;
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; NOTE: This routine must be called in protected mode.
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;
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assume ds:DGROUP,es:NOTHING,ss:NOTHING
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public StructureHeap
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StructureHeap proc near
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push ax
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push cx
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push es
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push bx ; most significant part of address
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push dx ; least significant part of address
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; Allocate selectors for the two sentinel blocks, and the initial free
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; block and link them at the start of the chain.
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;
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; Create the end sentinel
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add dx,word ptr cbHeapSize ;Calculate address of end sentinel
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adc bx,word ptr [cbHeapSize + 2]
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add dx,2*CB_MEMHDR
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adc bx,0
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call AddSelectorToChain ;Allocate/link the end sentinel
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; Initialize the ending sentinel block.
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assume es:MEMHDR
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xor ax,ax
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mov fBlkStatus,al
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mov cselBlkData,al
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mov selBlkData,ax
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mov selBlkOwner,0FFFFh
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mov cx,hmemHeap ; Save handle
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mov hBlockHandle,cx
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mov cx,dsegCurrent ; Save paragraph count
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mov dsegBlock,cx
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; Create the free block
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pop dx ; least significant part of address
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pop bx ; most significant part of address
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add dx,CB_MEMHDR ; Calculate address of Free block
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adc bx,0
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call AddSelectorToChain ; Allocate and link the Free Block
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; Initialize the header for the free data block.
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mov fBlkStatus,al
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mov cselBlkData,al
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mov selBlkData,ax
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mov selBlkOwner,ax
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mov cx,word ptr [cbHeapSize]
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mov word ptr [cbBlkLen],cx
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mov cx,word ptr [cbHeapSize+2]
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mov word ptr [cbBlkLen+2],cx
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; Create the starting sentinel
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sub dx,CB_MEMHDR ; Calculate address of start sentinel
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sbb bx,0
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call AddSelectorToChain ; Allocate and link the start sentinel
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; Initialize the starting sentinel block.
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mov fBlkStatus,al
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mov cselBlkData,al
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mov selBlkData,ax
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mov selBlkOwner,0FFFEh ;mark it as in use
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mov cx,hmemHeap ; Save handle
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mov hBlockHandle,cx
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mov cx,dsegCurrent ; Save paragraph count
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mov dsegBlock,cx
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pop es
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pop cx
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pop ax
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ret
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StructureHeap endp
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; -------------------------------------------------------
|
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; AddSelectorToChain -- This function will create a header block at a
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; specified address and link it to the head of the
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; header chain. It is the caller's responsibility
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; to initialize all fields in the header other
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; than the chain link pointers themselves.
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;
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; This function can only be called in protected mode.
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;
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; Input: BX - Most significant part of header address
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; DX - Least significant part of header address
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; Output: ES - selector for the new header
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|
; Errors: Carry flag set on error
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; Uses: all registers except ES preserved
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assume ds:DGROUP,es:NOTHING,ss:NOTHING
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public AddSelectorToChain
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AddSelectorToChain:
|
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push ax ; Save callers regs
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push bx ;
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push cx ;
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call AllocateSelector ; Get a free selector
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jc astcFail ; Jump on error
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mov cx,CB_MEMHDR - 1 ;
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cCall NSetSegmentDscr,<ax,bx,dx,0,cx,STD_DATA>
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|
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mov cx,selHeapStart ; Load old start of chain
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jcxz @f
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mov es,cx ; Point to old start of chain
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assume es:MEMHDR ;
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mov selBlkPrev,ax ; Link to new start of chain
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|
@@:
|
|
mov es,ax ; Point to new head of chain
|
|
mov selBlkNext,cx ; Link it to old head
|
|
mov selBlkPrev,0 ; NULL back pointer
|
|
mov selBlkHdr,ax ; Block header points to itself
|
|
mov selHeapStart,ax ; Store new head of chain
|
|
clc ; Flag no error
|
|
astcFail:
|
|
pop cx ; Restore Users regs
|
|
pop bx ;
|
|
pop ax ;
|
|
ret ; AddSelectorToChain
|
|
|
|
|
|
; -------------------------------------------------------
|
|
; AllocateXmem32 -- This function will return a 32-bit address and
|
|
; handle of a block of memory allocated in extended
|
|
; memory.
|
|
;
|
|
; Input: BX:CX - Size of block desired
|
|
; DX - Owner of block
|
|
; Output: BX:CX - Address of memory
|
|
; SI:DI - handle of memory
|
|
; Errors: Carry flag set on error
|
|
; Uses:
|
|
; -------------------------------------------------------
|
|
|
|
public AllocateXmem32
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
AllocateXmem32 proc near
|
|
|
|
FBOP BOP_DPMI, AllocXmem, FastBop
|
|
ret
|
|
|
|
AllocateXmem32 endp
|
|
|
|
|
|
; -------------------------------------------------------
|
|
; FreeXmem32 -- This function will free a block of extended memory
|
|
; allocated by AllocateXmem.
|
|
;
|
|
; Input: SI:DI - Handle of memory
|
|
; Errors: Carry flag set on error
|
|
; Uses:
|
|
; -------------------------------------------------------
|
|
|
|
public FreeXmem32
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
FreeXmem32 proc near
|
|
|
|
FBOP BOP_DPMI, FreeXmem, FastBop
|
|
ret
|
|
|
|
FreeXmem32 endp
|
|
|
|
|
|
DXPMCODE ends
|
|
|
|
DXCODE segment
|
|
assume cs:DXCODE
|
|
|
|
; -------------------------------------------------------
|
|
; ReleaseLowHeap -- This routine will release the
|
|
; special low memory heap. After this function is
|
|
; called, InitLowHeap must be called again before
|
|
; any other low heap functions can be used.
|
|
;
|
|
; Currently this routine doesn't bother to release
|
|
; selectors used by the blocks in the low heap (like
|
|
; ReleaseXmemHeap does) under the assumption that
|
|
; the DOS extender is about to terminate. If you are
|
|
; really going reinitialize the low heap with InitLowHeap,
|
|
; then you should do more clean up here.
|
|
;
|
|
; Input: none
|
|
; Output: none
|
|
; Errors:
|
|
; Uses: All preserved
|
|
;
|
|
; Note: This routine must be called in real mode!
|
|
|
|
assume ds:DGROUP,es:DGROUP,ss:NOTHING
|
|
public ReleaseLowHeap
|
|
|
|
ReleaseLowHeap proc near
|
|
|
|
push ax
|
|
push es
|
|
|
|
mov ax,segLowHeap ;make sure there really is a low heap
|
|
or ax,ax
|
|
jz rlh90
|
|
|
|
mov es,ax ;now use DOS to get rid of it
|
|
mov ah,49h
|
|
pushf
|
|
sub sp,8 ; make room for stack frame
|
|
push bp
|
|
mov bp,sp
|
|
push es
|
|
push ax
|
|
|
|
xor ax,ax
|
|
mov es,ax
|
|
mov [bp + 8],cs
|
|
mov [bp + 6],word ptr (offset rlh10)
|
|
mov ax,es:[21h*4]
|
|
mov [bp + 2],ax
|
|
mov ax,es:[21h*4 + 2]
|
|
mov [bp + 4],ax
|
|
pop ax
|
|
pop es
|
|
pop bp
|
|
retf
|
|
|
|
rlh10: xor ax,ax ;just to be tidy
|
|
mov segLowHeap,ax
|
|
mov selLowHeapStart,ax
|
|
|
|
rlh90:
|
|
pop es
|
|
pop ax
|
|
ret
|
|
|
|
ReleaseLowHeap endp
|
|
|
|
|
|
; -------------------------------------------------------
|
|
; ReleaseXmemHeap -- This routine will release memory
|
|
; used by the extended memory heap. After this function
|
|
; is called, no extended memory manager routines can
|
|
; be called except InitXmemHeap.
|
|
;
|
|
; Input:
|
|
; Output:
|
|
; Errors:
|
|
; Uses:
|
|
;
|
|
; Note: Do NOT enable interrupts while in protected mode!
|
|
|
|
assume ds:DGROUP,es:DGROUP,ss:NOTHING
|
|
public ReleaseXmemHeap
|
|
|
|
ReleaseXmemHeap:
|
|
push ax
|
|
push bx
|
|
push cx
|
|
push dx
|
|
push ds
|
|
push es
|
|
|
|
SwitchToProtectedMode ; Needed for selector juggling
|
|
|
|
ifdef MD
|
|
call CheckXmemHeap
|
|
endif
|
|
mov bx,selHeapStart ; Point to the start of the block chain
|
|
mov es,bx ;
|
|
assume es:MEMHDR ;
|
|
;
|
|
; This is the start of a loop on all blocks. ES and BX both contain the
|
|
; selector for the current block, or zero if at the end of the chain.
|
|
rxh100:
|
|
or bx,bx ; End of chain?
|
|
jz rxhEnd ; Yes - Jump
|
|
mov cl,cselBlkData ; Load number of data segments
|
|
xor ch,ch ;
|
|
jcxz rxh200 ; Jump if nothing to do
|
|
mov ax,selBlkData ; Load first data segment
|
|
and ax,SELECTOR_INDEX ; Treat like GDT entry for FreeSelector
|
|
rxh110:
|
|
push ax ; Since it is destroyed by FreeSelector
|
|
call FreeSelector ; Free each of the data selectors
|
|
pop ax ;
|
|
add ax,8 ; Point to the next data descriptor
|
|
loop rxh110 ;
|
|
;
|
|
; All data descriptors for this block now free (if there ever were any)
|
|
rxh200:
|
|
push selBlkNext ; Push pointer to the next block in the chain
|
|
push es ; Push the pointer to this one
|
|
cmp selBlkOwner,0FFFFh ; Is this an end sentinel ?
|
|
jne rxh300 ; No - jump
|
|
;
|
|
; Time to free a HIMEM allocated memory blcok
|
|
rxh210:
|
|
mov dx,hBlockHandle ;
|
|
push dx ; Since the data may move after the unlock
|
|
ASSUME es:NOTHING ;
|
|
pmxmssvc 0Dh,disable ;unlock the memory block containing the heap
|
|
pop dx ;
|
|
pmxmssvc 0Ah,disable ;free the block
|
|
;
|
|
; Time to free the header selector.
|
|
rxh300:
|
|
pop ax ; Retrieve the selector for the current header
|
|
pop bx ; Retrieve the selector for the next one
|
|
mov es,bx ;
|
|
call FreeSelector ; Free the selector for the current header
|
|
jmp rxh100 ; Loop for the next block
|
|
;
|
|
; All done
|
|
rxhEnd:
|
|
mov selHeapStart,0 ; Point to the start of the block chain
|
|
ifdef MD
|
|
call CheckXmemHeap
|
|
endif
|
|
SwitchToRealMode ; Restore callers environment
|
|
sti ;
|
|
pop es
|
|
pop ds
|
|
pop dx
|
|
pop cx
|
|
pop bx
|
|
pop ax
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
|
|
DXCODE ends
|
|
|
|
; -------------------------------------------------------
|
|
subttl Main Routines
|
|
page
|
|
; -------------------------------------------------------
|
|
|
|
DXPMCODE segment
|
|
assume cs:DXPMCODE
|
|
|
|
; -------------------------------------------------------
|
|
; MAIN MEMORY MANAGEMENT ROUTINES
|
|
; -------------------------------------------------------
|
|
;
|
|
; AllocateLowBlock -- This function will allocate a block
|
|
; of memory from the special low memory heap.
|
|
; If the requested block is larger than 64k, multiple segment
|
|
; descriptors will be allocated, one for each full 64k and one
|
|
; for whatever is left over. When multiple segment descriptors
|
|
; are created, the selectors will differ by 8 for each segment.
|
|
; (i.e. the returned selector accesses the first 64k, add 8 to
|
|
; get to the next 64k, etc.)
|
|
;
|
|
; Input: CX - low word of requested block size
|
|
; DX - high word of requested block size
|
|
; Output: AX - initial selector for the memory block
|
|
; Errors: returns CY set and size of largest free memory block in CX,DX.
|
|
; This can occur either because there isn't a large enough
|
|
; free block in the memory pool, or there isn't a contiguous
|
|
; range of free segment descriptors that is large enough.
|
|
; Uses: AX, all else preserved. Modifies the segment descriptors
|
|
; for the SEL_SCR0 and SEL_SCR1 segments
|
|
;
|
|
; Note: This routine is _very_ similar to AllocateXmemBlock,
|
|
; but just different enough that it's a separate routine.
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public AllocateLowBlock
|
|
|
|
AllocateLowBlock proc near
|
|
|
|
push bp
|
|
mov bp,sp
|
|
sub sp,14
|
|
push es
|
|
push si
|
|
push bx
|
|
push cx
|
|
push dx
|
|
|
|
Segm equ word ptr [bp - 2]
|
|
StartSel equ word ptr [bp - 4]
|
|
Largest equ word ptr [bp - 6]
|
|
MemSize equ [bp - 10]
|
|
cSelector equ word ptr [bp - 12]
|
|
selHeader equ word ptr [bp - 14]
|
|
|
|
mov word ptr MemSize,cx
|
|
mov word ptr MemSize + 2,dx
|
|
|
|
;
|
|
; See if we need to use wow kernel to manage low memory
|
|
;
|
|
mov ax,word ptr [LowMemAllocFn]
|
|
or ax,word ptr [LowMemAllocFn + 2]
|
|
je alm3
|
|
jmp alm130
|
|
;
|
|
; Round up to the next paragraph
|
|
;
|
|
alm3: add cx,15
|
|
adc dx,0
|
|
and cx,0FFF0h
|
|
|
|
;
|
|
; Form a paragraph count
|
|
;
|
|
mov bx,cx
|
|
shr bx,4
|
|
shl dx,12
|
|
or bx,dx
|
|
|
|
;
|
|
; Add one to make room for the heap header
|
|
;
|
|
cmp bx,0ffffh
|
|
je alm5 ; won't succed, but get size
|
|
|
|
inc bx
|
|
alm5:
|
|
;
|
|
; Switch to real mode and allocate the memory
|
|
;
|
|
SwitchToRealMode
|
|
|
|
mov ax,4800h
|
|
int 21h ; call dos
|
|
|
|
jnc alm10
|
|
|
|
mov Segm,ax
|
|
mov Largest,bx
|
|
mov cx,0
|
|
jmp alm20
|
|
;
|
|
; Remember the values returned
|
|
;
|
|
|
|
alm10: mov Segm,ax
|
|
mov cx,1
|
|
|
|
alm20: SwitchToProtectedMode
|
|
cmp cx,0
|
|
jne alm40
|
|
|
|
;
|
|
; return an error
|
|
;
|
|
|
|
alm30: mov cx,bx
|
|
mov dx,bx
|
|
shr dx,12
|
|
shl cx,4 ; form bytes available
|
|
mov ax,Segm ; actually error code for fail
|
|
add sp,4 ; skip cx,dx
|
|
stc
|
|
jmp alm110
|
|
|
|
alm40: mov ax,word ptr MemSize + 2
|
|
mov bx,word ptr MemSize
|
|
|
|
or bx, bx
|
|
jnz short alm44
|
|
or ax, ax
|
|
jz short alm45 ; if zero then don't adjust
|
|
|
|
alm44:
|
|
sub bx,1
|
|
sbb ax,0 ; go from size to limit
|
|
alm45:
|
|
mov word ptr MemSize + 2,ax
|
|
mov word ptr MemSize,bx
|
|
inc ax ; we always want 2 more
|
|
inc ax
|
|
mov cSelector,ax
|
|
xor cx, cx ;allocate from lower range
|
|
call AllocateSelectorBlock
|
|
jnc alm50
|
|
|
|
mov ax,8 ; insufficient memory
|
|
mov bx,Largest
|
|
jmp alm30
|
|
|
|
alm50: or ax,STD_RING
|
|
mov si,ax
|
|
mov StartSel,ax
|
|
mov ax,word ptr MemSize + 2
|
|
mov bx,word ptr MemSize ; ax:bx - block size
|
|
mov cx,Segm
|
|
mov dx,cx
|
|
shr cx,12
|
|
shl dx,4 ; cx:dx - block base
|
|
;
|
|
; Set up the first one to have the entire limit
|
|
;
|
|
cCall NSetSegmentDscr,<si,cx,dx,ax,bx,STD_DATA>
|
|
|
|
;
|
|
; Set up the rest to have 64K limits
|
|
;
|
|
|
|
dec ax ; already set one
|
|
cmp ax,0FFFFh
|
|
je alm80
|
|
|
|
cmp ax,0
|
|
je alm70
|
|
|
|
mov di,0FFFFh
|
|
alm60: add si,8
|
|
inc cx ; add 64K to base
|
|
|
|
cCall NSetSegmentDscr,<si,cx,dx,0,di,STD_DATA>
|
|
|
|
dec ax
|
|
cmp ax,0
|
|
jne alm60
|
|
|
|
;
|
|
; Just one selector left, so set the correct limit
|
|
;
|
|
|
|
alm70: add si,8
|
|
inc cx
|
|
cCall NSetSegmentDscr,<si,cx,dx,0,bx,STD_DATA>
|
|
|
|
;
|
|
; Set up header
|
|
;
|
|
|
|
alm80: mov ax,Segm
|
|
mov bx,ax
|
|
shr ax,12
|
|
shl bx,4 ; ax:bx = base of header
|
|
add bx,word ptr MemSize
|
|
adc ax,word ptr MemSize + 2
|
|
add si,8
|
|
cCall NSetSegmentDscr,<si,ax,bx,0,CB_MEMHDR,STD_DATA>
|
|
|
|
;
|
|
; Set up values in header and add to chain
|
|
;
|
|
mov es,si
|
|
mov selHeader,si
|
|
assume es:MEMHDR
|
|
mov [selBlkHdr],si
|
|
mov ax,StartSel
|
|
mov [selBlkData],ax
|
|
mov ax,cSelector
|
|
mov [cselBlkData],al
|
|
mov ax,selPSPChild
|
|
mov [selBlkOwner],ax
|
|
mov ax,Segm
|
|
mov [hBlockHandle],ax
|
|
mov ax,selLowHeapStart
|
|
mov [selBlkNext],ax
|
|
mov bx,0
|
|
mov [selBlkPrev],bx
|
|
or ax,ax
|
|
jz alm100
|
|
|
|
mov bx,es
|
|
mov es,ax
|
|
mov [selBlkPrev],bx
|
|
|
|
;
|
|
; set up return values
|
|
;
|
|
alm100: mov ax,selHeader
|
|
mov selLowHeapStart,ax
|
|
mov ax,StartSel
|
|
clc
|
|
alm105: pop dx
|
|
pop cx
|
|
alm110: pop bx
|
|
pop si
|
|
pop es
|
|
mov sp,bp
|
|
pop bp
|
|
ret
|
|
|
|
alm130: push dx
|
|
push cx
|
|
call [LowMemAllocFn]
|
|
or ax,ax
|
|
jz alm140
|
|
clc
|
|
jmp alm105
|
|
|
|
alm140: xor cx,cx
|
|
stc
|
|
add sp,4
|
|
jmp alm110
|
|
|
|
AllocateLowBlock endp
|
|
|
|
|
|
; -------------------------------------------------------
|
|
; FreeLowBlock -- This function will free the low heap
|
|
; memory block specified by the given selector. It
|
|
; will return the memory block to the free memory pool,
|
|
; and release all selectors used by this block.
|
|
;
|
|
; Input: AX - selector of the data block to free
|
|
; Output: none
|
|
; Errors: returns CY set if invalid selector
|
|
; Uses: AX, all other registers preserved
|
|
; Modifies the descriptor for segment SEL_SCR0
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public FreeLowBlock
|
|
|
|
FreeLowBlock proc near
|
|
push bp
|
|
mov bp,sp
|
|
sub sp,4
|
|
Segm equ word ptr [bp - 2]
|
|
HeaderSel equ word ptr [bp - 4]
|
|
push es
|
|
push bx
|
|
push cx
|
|
|
|
;
|
|
; See if we need to use the wow kernel to manage memory
|
|
;
|
|
mov bx,word ptr [LowMemFreeFn]
|
|
or bx,word ptr [LowMemFreeFn + 2]
|
|
jz flm5
|
|
jmp flm130
|
|
|
|
;
|
|
; search for the block to free
|
|
;
|
|
flm5: mov bx,selLowHeapStart
|
|
flm10: or bx,bx ; any low blocks?
|
|
jz flm100
|
|
|
|
mov es,bx
|
|
assume es:MEMHDR
|
|
|
|
cmp [selBlkData],ax
|
|
je flm30 ; found the correct block
|
|
|
|
mov bx,[selBlkNext]
|
|
jmp flm10
|
|
|
|
;
|
|
; Unlink the block from the list
|
|
;
|
|
flm30: mov ax,es
|
|
mov HeaderSel,ax
|
|
|
|
mov ax,[selBlkPrev]
|
|
mov bx,[selBlkNext]
|
|
cmp ax,0
|
|
je flm40
|
|
|
|
mov es,ax
|
|
mov [selBlkNext],bx
|
|
jmp flm50
|
|
|
|
flm40: mov SelLowHeapStart,bx
|
|
flm50: cmp bx,0
|
|
je flm60
|
|
|
|
mov es,bx
|
|
mov [selBlkPrev],ax
|
|
|
|
flm60: mov ax,HeaderSel
|
|
mov es,ax
|
|
mov ax,[hBlockHandle]
|
|
mov Segm,ax
|
|
|
|
mov ax,[selBlkData]
|
|
xor cx,cx
|
|
mov cl,[cselBlkData]
|
|
push 0
|
|
pop es
|
|
call FreeSelectorBlock
|
|
|
|
SwitchToRealMode
|
|
mov ax,Segm
|
|
mov es,ax
|
|
mov ax,4900h
|
|
int 21h ; free the memory
|
|
|
|
push ax ; save return code
|
|
jnc flm70
|
|
|
|
mov cx,0 ; error
|
|
jmp flm80
|
|
|
|
flm70: mov cx,1 ; no error
|
|
flm80: SwitchToProtectedMode
|
|
pop ax
|
|
cmp cx,0
|
|
je flm100 ; error path
|
|
|
|
flm85: clc
|
|
flm90: pop cx
|
|
pop bx
|
|
pop es
|
|
mov sp,bp
|
|
pop bp
|
|
ret
|
|
|
|
flm100: stc
|
|
jmp flm90
|
|
|
|
flm130: push ax
|
|
call [LowMemFreeFn]
|
|
or ax,ax
|
|
jz flm85
|
|
|
|
mov ax,9
|
|
stc
|
|
jmp flm90
|
|
|
|
FreeLowBlock endp
|
|
|
|
; -------------------------------------------------------
|
|
;
|
|
; AllocateXmemBlock -- This function will allocate a block
|
|
; of extended memory and return selectors for accessing it.
|
|
; If the requested block is larger than 64k, multiple segment
|
|
; descriptors will be allocated, one for each full 64k and one
|
|
; for whatever is left over. When multiple segment descriptors
|
|
; are created, the selectors will differ by 8 for each segment.
|
|
; (i.e. the returned selector accesses the first 64k, add 8 to
|
|
; get to the next 64k, etc.)
|
|
;
|
|
; Input: BL - flag controlling allocation of selectors,
|
|
; if 0 - a selector will be allocated for each 64k
|
|
; if != 0 - only one selector will be allocated to
|
|
; the block.
|
|
; CX - low word of requested block size
|
|
; DX - high word of requested block size
|
|
; Output: AX - initial selector for the memory block
|
|
; Errors: returns CY set and size of largest free memory block in CX,DX.
|
|
; This can occur either because there isn't a large enough
|
|
; free block in the memory pool, or there isn't a contiguous
|
|
; range of free segment descriptors that is large enough.
|
|
; Uses: AX, all else preserved. Modifies the segment descriptors
|
|
; for the SEL_SCR0 and SEL_SCR1 segments
|
|
;
|
|
; Notes: Hard coding an int 3 in this routine is fatal. This routine
|
|
; is used to allocate the stack used for exception handling.
|
|
;
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public AllocateXmemBlock
|
|
|
|
AllocateXmemBlock proc near
|
|
|
|
axb1: push bp
|
|
mov bp,sp
|
|
sub sp,20
|
|
push es
|
|
push bx
|
|
push si
|
|
push di
|
|
push cx
|
|
push dx
|
|
|
|
AllocFlag equ byte ptr [bp - 2]
|
|
cSelector equ word ptr [bp - 4]
|
|
MemHandle equ [bp - 8]
|
|
MemSize equ [bp - 12]
|
|
MemAddr equ [bp - 16]
|
|
StartSel equ word ptr [bp - 18]
|
|
HeaderSel equ word ptr [bp - 20]
|
|
|
|
mov AllocFlag,bl
|
|
mov word ptr MemSize,cx
|
|
mov word ptr MemSize + 2,dx
|
|
mov word ptr MemHandle,0
|
|
mov word ptr MemHandle + 2,0
|
|
|
|
;
|
|
; Save room for header
|
|
;
|
|
add cx,16
|
|
adc dx,0
|
|
|
|
mov bx,dx
|
|
mov dx, selPSPChild
|
|
|
|
call AllocateXmem32
|
|
|
|
jnc axb40
|
|
jmp axb130
|
|
|
|
axb40: mov word ptr MemAddr,cx
|
|
mov word ptr MemAddr + 2,bx
|
|
mov word ptr MemHandle,di
|
|
mov word ptr MemHandle + 2,si
|
|
;
|
|
; Change size to limit
|
|
;
|
|
mov ax,word ptr MemSize + 2
|
|
mov bx,word ptr MemSize
|
|
sub bx,1
|
|
sbb ax,0 ; size -> limit
|
|
mov word ptr MemSize,bx
|
|
mov word ptr MemSize + 2,ax
|
|
|
|
;
|
|
; Figure out how many selectors to allocate
|
|
;
|
|
cmp AllocFlag,0
|
|
jne axb50
|
|
|
|
inc ax
|
|
jmp axb60
|
|
|
|
axb50: mov ax,1
|
|
|
|
;
|
|
; Add one additional for the header block
|
|
;
|
|
axb60: inc ax
|
|
mov cSelector,ax
|
|
|
|
;
|
|
; Allocate the selectors
|
|
;
|
|
xor cx,cx ; allocate from lower range
|
|
call AllocateSelectorBlock
|
|
jnc axb65
|
|
|
|
jmp axb120
|
|
|
|
axb65: or ax,STD_RING
|
|
mov StartSel,ax
|
|
|
|
;
|
|
; Set up the first selector to have the entire limit
|
|
;
|
|
mov di,cSelector
|
|
mov si,ax
|
|
mov ax,word ptr MemSize + 2
|
|
mov bx,word ptr MemSize
|
|
mov cx,word ptr MemAddr + 2
|
|
mov dx,word ptr MemAddr
|
|
add dx,16 ; room for header
|
|
adc cx,0
|
|
cCall NSetSegmentDscr,<si,cx,dx,ax,bx,STD_DATA>
|
|
dec di
|
|
dec ax
|
|
add si,8
|
|
|
|
cmp di,1
|
|
je axb90
|
|
|
|
;
|
|
; Set up the rest with 64K limits
|
|
;
|
|
axb70: cmp ax,0
|
|
je axb80
|
|
|
|
inc cx
|
|
cCall NSetSegmentDscr,<si,cx,dx,0,0FFFFh,STD_DATA>
|
|
dec ax
|
|
add si,8
|
|
jmp axb70
|
|
|
|
;
|
|
; Set up the last one with the remaining limit
|
|
;
|
|
axb80: inc cx
|
|
cCall NSetSegmentDscr,<si,cx,dx,0,bx,STD_DATA>
|
|
add si,8
|
|
|
|
;
|
|
; Set up Header selector
|
|
;
|
|
axb90: mov ax,word ptr MemAddr + 2
|
|
mov bx,word ptr MemAddr
|
|
cCall NSetSegmentDscr,<si,ax,bx,0,CB_MEMHDR,STD_DATA>
|
|
mov HeaderSel,si
|
|
|
|
;
|
|
; Set up header
|
|
;
|
|
mov es,si
|
|
assume es:MEMHDR
|
|
mov [selBlkHdr],si
|
|
mov ax,StartSel
|
|
mov [selBlkData],ax
|
|
mov ax,cSelector
|
|
mov [cselBlkData],al
|
|
mov ax,selPSPChild
|
|
mov [selBlkOwner],ax
|
|
mov ax,MemHandle
|
|
mov [hBlockHandle],ax
|
|
mov ax,word ptr MemHandle + 2
|
|
mov [dsegBlock],ax ; use for high half handle
|
|
mov ax,selHiHeapStart
|
|
mov [selBlkNext],ax
|
|
mov bx,0
|
|
mov [selBlkPrev],bx
|
|
or ax,ax
|
|
jz axb100
|
|
|
|
mov bx,es
|
|
mov es,ax
|
|
mov [selBlkPrev],bx
|
|
axb100: mov ax,HeaderSel
|
|
mov selHiHeapStart,ax
|
|
|
|
;
|
|
; return information to the caller
|
|
;
|
|
clc
|
|
mov ax,StartSel
|
|
pop dx
|
|
pop cx
|
|
axb110: pop di
|
|
pop si
|
|
pop bx
|
|
pop es
|
|
mov sp,bp
|
|
pop bp
|
|
ret
|
|
|
|
;
|
|
; Error
|
|
;
|
|
|
|
axb120: mov dx,word ptr MemHandle
|
|
or dx,word ptr MemHandle + 2
|
|
jz axb130
|
|
|
|
mov di,word ptr MemHandle
|
|
mov si,word ptr MemHandle + 2
|
|
|
|
FBOP BOP_DPMI, FreeXmem, FastBop
|
|
;
|
|
; Get largest free block
|
|
;
|
|
axb130: pmxmssvc 08h
|
|
mov dx,ax
|
|
mov cx,ax
|
|
shl cx,10
|
|
shr dx,6
|
|
add sp,4 ; skip cx,dx on stack
|
|
stc
|
|
jmp axb110
|
|
|
|
AllocateXmemBlock endp
|
|
|
|
; -------------------------------------------------------
|
|
; FreeXmemBlock -- This function will free the extended
|
|
; memory block specified by the given selector. It
|
|
; will return the memory block to the free memory pool,
|
|
; and release all selectors used by this block.
|
|
;
|
|
; Input: AX - selector of the data block to free
|
|
; Output: none
|
|
; Errors: returns CY set if invalid selector
|
|
; Uses: AX, all other registers preserved
|
|
; Modifies the descriptor for segment SEL_SCR0
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public FreeXmemBlock
|
|
|
|
|
|
FreeXmemBlock:
|
|
|
|
fxb1: push bp
|
|
mov bp,sp
|
|
sub sp,6
|
|
HeaderSel equ word ptr [bp - 2]
|
|
MemHandle equ [bp - 6]
|
|
push es
|
|
push bx
|
|
push si
|
|
push di
|
|
push dx
|
|
push cx
|
|
|
|
;
|
|
; search for the block to free
|
|
;
|
|
mov bx,selHiHeapStart
|
|
fxb10: or bx,bx ; any hi blocks?
|
|
jnz fxb20
|
|
jmp fxb100
|
|
|
|
fxb20: mov es,bx
|
|
assume es:MEMHDR
|
|
|
|
cmp [selBlkData],ax
|
|
je fxb30 ; found the correct block
|
|
|
|
mov bx,[selBlkNext]
|
|
jmp fxb10
|
|
|
|
;
|
|
; Unlink the block from the list
|
|
;
|
|
fxb30: mov ax,es
|
|
mov HeaderSel,ax
|
|
|
|
mov ax,[selBlkPrev]
|
|
mov bx,[selBlkNext]
|
|
cmp ax,0
|
|
je fxb40
|
|
|
|
mov es,ax
|
|
mov [selBlkNext],bx
|
|
jmp fxb50
|
|
|
|
fxb40: mov SelHiHeapStart,bx
|
|
fxb50: cmp bx,0
|
|
je fxb60
|
|
|
|
mov es,bx
|
|
mov [selBlkPrev],ax
|
|
|
|
fxb60: mov ax,HeaderSel
|
|
|
|
mov es,ax
|
|
mov dx,[dsegBlock] ; high half handle
|
|
mov word ptr MemHandle + 2,dx
|
|
mov dx,[hBlockHandle]
|
|
mov word ptr MemHandle,dx
|
|
|
|
;
|
|
; Free the selectors
|
|
;
|
|
mov ax,[selBlkData]
|
|
xor cx,cx
|
|
mov cl,[cselBlkData]
|
|
push 0
|
|
pop es
|
|
assume es:nothing
|
|
call FreeSelectorBlock
|
|
|
|
mov si,word ptr MemHandle + 2
|
|
mov di,word ptr MemHandle
|
|
|
|
call FreeXmem32
|
|
clc
|
|
|
|
fxb90: pop cx
|
|
pop dx
|
|
pop di
|
|
pop si
|
|
pop bx
|
|
pop es
|
|
mov sp,bp
|
|
pop bp
|
|
ret
|
|
|
|
fxb100: stc
|
|
jmp fxb90
|
|
|
|
; -------------------------------------------------------
|
|
; ModifyXmemBlock -- This function will modify the size
|
|
; of the specified extended memory block to the new
|
|
; size specified by CX,DX. If the block is being
|
|
; shrunk, the new size must be at least CB_HDRSIZ bytes
|
|
; smaller than the old size, or nothing is done.If the
|
|
; block grows beyond the next 64k boundary,
|
|
; it may be necessary to allocate another segment
|
|
; descriptor for it. If this is not possible, the grow
|
|
; will fail.
|
|
;
|
|
; Input: AX - segment selector for the data block to modify
|
|
; BL - flag controlling allocation of selectors to block,
|
|
; if 0 - selectors will be allocated for each 64k
|
|
; if != 0 - only one selector is allocated to block
|
|
; CX - low word of new desired size
|
|
; DX - high word of new desired size
|
|
; Output: none
|
|
; Errors: CY set if unable to accomplish the request.
|
|
; returns error code in AX.
|
|
; CX,DX will be set to the largest possible size that the
|
|
; block could be modified to have
|
|
; Uses: AX,CX,DX,Flags
|
|
|
|
assume ds:DGROUP,es:NOTHING
|
|
public ModifyXmemBlock
|
|
|
|
ModifyXmemBlock proc near
|
|
mxb1: push bp
|
|
mov bp,sp
|
|
sub sp,20
|
|
HeaderSel equ word ptr [bp - 2]
|
|
AllocFlags equ byte ptr [bp - 4]
|
|
MemSize equ [bp - 8]
|
|
MemAddr equ [bp - 12]
|
|
Success equ word ptr [bp - 14]
|
|
cSelector equ word ptr [bp - 16]
|
|
BlockHandle equ word ptr [bp - 20]
|
|
push es
|
|
push bx
|
|
push cx
|
|
push dx
|
|
|
|
mov word ptr MemSize + 2,dx
|
|
mov word ptr MemSize,cx
|
|
mov AllocFlags,bl
|
|
mov Success,1
|
|
|
|
;
|
|
; Search for the block to resize
|
|
;
|
|
mov bx,selHiHeapStart
|
|
mxb10: or bx,bx ; any hi blocks?
|
|
jnz mxb15
|
|
jmp mxb140
|
|
|
|
mxb15: mov es,bx
|
|
assume es:MEMHDR
|
|
|
|
cmp [selBlkData],ax
|
|
je mxb30 ; found the correct block
|
|
|
|
mov bx,[selBlkNext]
|
|
jmp mxb10
|
|
|
|
;
|
|
; Calculate the number of selectors needed
|
|
;
|
|
mxb30: mov HeaderSel,es
|
|
test AllocFlags,1
|
|
jne mxb40
|
|
|
|
sub cx, 1 ; size -> limit
|
|
sbb dx,0
|
|
inc dl
|
|
jmp mxb50
|
|
|
|
mxb40: mov dl,1
|
|
mxb50: inc dl ; always need 1 more
|
|
|
|
;
|
|
; See if we have enough selectors
|
|
;
|
|
cmp dl,[cselBlkData]
|
|
jna mxb55
|
|
jmp mxb120
|
|
|
|
mxb55: and dl,0ffh
|
|
mov cSelector,dx
|
|
mov dx,[dsegBlock]
|
|
mov word ptr BlockHandle + 2,dx
|
|
mov dx,[hBlockHandle]
|
|
mov word ptr BlockHandle,dx
|
|
|
|
mov bx,word ptr MemSize + 2
|
|
mov cx,word ptr MemSize
|
|
add cx,010h
|
|
adc bx,0
|
|
mov si,word ptr BlockHandle + 2
|
|
mov di,word ptr BlockHandle
|
|
|
|
FBOP BOP_DPMI, ReallocXmem, FastBop
|
|
jnc mxb60
|
|
|
|
mov Success,0
|
|
|
|
mxb60: mov word ptr MemAddr,cx
|
|
mov word ptr MemAddr + 2,bx
|
|
mov word ptr BlockHandle,di
|
|
mov word ptr BlockHandle + 2,si
|
|
;
|
|
; Fix the base of the Header selector
|
|
;
|
|
mov bx,word ptr MemAddr + 2
|
|
mov dx,word ptr MemAddr
|
|
mov ax,HeaderSel
|
|
call SetSegmentAddress
|
|
mov es,ax
|
|
|
|
;
|
|
; Fix the handle (may have changed
|
|
;
|
|
mov dx,word ptr BlockHandle
|
|
mov [hBlockHandle],dx
|
|
mov dx,word ptr BlockHandle + 2
|
|
mov [dsegBlock],dx
|
|
|
|
;
|
|
; Change size to limit
|
|
;
|
|
mov ax,word ptr MemSize + 2
|
|
mov bx,word ptr MemSize
|
|
sub bx,1
|
|
sbb ax,0 ; size -> limit
|
|
mov word ptr MemSize,bx
|
|
mov word ptr MemSize + 2,ax
|
|
|
|
;
|
|
; Set up the first selector to have the entire limit
|
|
;
|
|
mov di,cSelector
|
|
mov si,[selBlkData]
|
|
mov ax,word ptr MemSize + 2
|
|
mov bx,word ptr MemSize
|
|
mov cx,word ptr MemAddr + 2
|
|
mov dx,word ptr MemAddr
|
|
add dx,16 ; room for header
|
|
adc cx,0
|
|
cCall NSetSegmentDscr,<si,cx,dx,ax,bx,STD_DATA>
|
|
dec di
|
|
dec ax
|
|
add si,8
|
|
|
|
cmp di,1
|
|
je mxb100
|
|
|
|
;
|
|
; Set up the rest with 64K limits
|
|
;
|
|
mxb80: cmp ax,0
|
|
je mxb90
|
|
|
|
inc cx
|
|
cCall NSetSegmentDscr,<si,cx,dx,0,0FFFFh,STD_DATA>
|
|
dec ax
|
|
add si,8
|
|
jmp mxb80
|
|
|
|
;
|
|
; Set up the last one with the remaining limit
|
|
;
|
|
mxb90: inc cx
|
|
cCall NSetSegmentDscr,<si,cx,dx,0,bx,STD_DATA>
|
|
add si,8
|
|
|
|
;
|
|
; Were we successfull?
|
|
;
|
|
mxb100: cmp Success,1
|
|
jne mxb130
|
|
|
|
clc
|
|
pop dx
|
|
pop cx
|
|
mxb110: pop bx
|
|
pop es
|
|
mov sp,bp
|
|
pop bp
|
|
ret
|
|
|
|
;
|
|
; We had an error, not enough selectors. Figure out how large
|
|
; it could have been
|
|
;
|
|
mxb120: xor dx,dx
|
|
xor cx,cx
|
|
mov dl,[cselBlkData]
|
|
dec dl ; don't count header sel
|
|
mov ax,8
|
|
add sp,4 ; pop cx,dx
|
|
stc
|
|
jmp mxb110
|
|
|
|
;
|
|
; We had an error calling xms. Get the largest block
|
|
;
|
|
mxb130: pmxmssvc 08h
|
|
mov cx,ax ; convert to bytes
|
|
mov dx,ax
|
|
shl cx,10
|
|
shr dx,6
|
|
mov ax,8
|
|
add sp,4
|
|
stc
|
|
jmp mxb110
|
|
|
|
;
|
|
; We had an error, invalid selector
|
|
;
|
|
mxb140: mov ax,9
|
|
add sp,4
|
|
stc
|
|
jmp mxb110
|
|
|
|
ModifyXmemBlock endp
|
|
ret
|
|
|
|
|
|
;
|
|
; -------------------------------------------------------
|
|
subttl Utility Routines
|
|
page
|
|
; -------------------------------------------------------
|
|
; UTIITY ROUTINES
|
|
; -------------------------------------------------------
|
|
|
|
; -------------------------------------------------------
|
|
; CalculateMaximumSegmentSpace -- This function will see if there
|
|
; are enough free segments available
|
|
; to expand a block of memory.
|
|
; If not it returns with carry set
|
|
; and the maximum space available.
|
|
;
|
|
; Input; ES - segment selector for the data block to modify
|
|
; CX - low word of new desired size
|
|
; DX - high word of new desired size
|
|
;
|
|
; Output CX - / If CY set: The maximum available
|
|
; DX - \ If CY not set: Unchanged
|
|
; Errors: CY set if unable to accomplish the request.
|
|
; CX,DX will be set to the largest possible size that the
|
|
; block could be modified to have
|
|
; Uses: AX,CX,DX,Flags
|
|
|
|
assume ds:DGROUP,es:MEMHDR
|
|
public CalculateMaximumSegmentSpace
|
|
|
|
CalculateMaximumSegmentSpace:
|
|
push bx
|
|
push es
|
|
xor bx,bx
|
|
mov bl,cselBlkData ; Allocated selector count
|
|
shl bx,3 ; Convert to byte offset
|
|
add bx,selBlkData ; Add starting data selector offset
|
|
and bx,SELECTOR_INDEX ; Treat it as a GDT selector
|
|
mov es,selGDT ; Base the global descriptor table
|
|
assume es:NOTHING ;
|
|
|
|
; Count through the immediately following selectors
|
|
|
|
cmssLoop:
|
|
cmp bx,word ptr bpgdt ; Off the end of the GDT ?
|
|
ja cmssOutOfSelectors ; Yes - Jump
|
|
cmp word ptr es:[bx].arbSegAccess,0 ; Is the next selector free ?
|
|
jne cmssOutOfSelectors ; No - jump
|
|
|
|
; Point to the next selector
|
|
|
|
add bx,8 ; Increment to next selector
|
|
jnc cmssLoop ; Try the next one
|
|
|
|
; BX points to the first following selector which is not free
|
|
|
|
cmssOutOfSelectors:
|
|
pop es ; Recover block header segment
|
|
assume es:MEMHDR
|
|
push dx ; Subtract base selector address
|
|
mov dx,selBlkData
|
|
and dx,SELECTOR_INDEX
|
|
sub bx,dx
|
|
pop dx
|
|
shr bx,3 ; Number of contiguous selectors available
|
|
cmp bx,dx ; Is it enough ?
|
|
jb cmssNotEnough ; No - jump
|
|
jne cmssOK ; Yes - jump
|
|
or cx,cx ; Don't know - Look at less significant part
|
|
jnz cmssNotEnough ; Yes it will fit after all - jump
|
|
|
|
; Not enough free selectors
|
|
|
|
cmssNotEnough:
|
|
mov dx,bx ; Put max available in CX&DX
|
|
xor cx,cx ;
|
|
stc ; Flag error
|
|
jmp short cmssExit ; Leave
|
|
;
|
|
; There are enough selectors to satisfy the request
|
|
cmssOK:
|
|
clc ; Reset the error flag
|
|
;
|
|
; All Done
|
|
cmssExit:
|
|
pop bx ; Restore registers
|
|
ret ; CalculateMaximumSegmentSpace
|
|
|
|
; -------------------------------------------------------
|
|
; CalculateMaximumSpace -- This function will see if there
|
|
; is room to expand a block of memory.
|
|
; If not it returns with carry set
|
|
; and the maximum space available.
|
|
;
|
|
; Input: AL - check selectors yes/no flag - 0 = yes, !0 = no
|
|
; ES - segment selector for the data block to modify
|
|
; CX - low word of new desired size
|
|
; DX - high word of new desired size
|
|
; Output: AX - Strategy used: 0 = expand into same block
|
|
; 1 = expand into next block
|
|
; 2 = expand into next and previous blocks
|
|
; 3 = allocate a new block and transfer data
|
|
; 4 = move lower and higher blocks
|
|
; CX - / If CY set: The maximum available
|
|
; DX - \ If CY not set: Unchanged
|
|
; Errors: CY set if unable to accomplish the request.
|
|
; CX,DX will be set to the largest possible size that the
|
|
; block could be modified to have
|
|
; Uses: AX,CX,DX,Flags
|
|
|
|
assume ds:DGROUP,es:MEMHDR
|
|
public CalculateMaximumSpace
|
|
|
|
CalculateMaximumSpace proc near
|
|
|
|
push bp
|
|
mov bp,sp
|
|
push es
|
|
push cx ; Save required length
|
|
push dx
|
|
push ax ; Save segment/selector flag
|
|
|
|
mov cx,word ptr [cbBlkLen] ; Load present length
|
|
mov dx,word ptr [cbBlkLen+2] ;
|
|
mov ax,0 ; Load strategy code
|
|
cmp dx,word ptr [bp - 6] ; Compare available with needed
|
|
jb cms90 ; Jump if it doesn't fit
|
|
ja cmsOKa ; Jump if it fits
|
|
cmp cx,word ptr [bp - 4] ;
|
|
jb cms90 ;
|
|
cmsOKa:
|
|
jmp cmsOK
|
|
|
|
; There is not enough room in the current block. See if the following
|
|
; one is free
|
|
|
|
cms90:
|
|
mov es,[selBlkNext] ; Point to the following block
|
|
cmp [selBlkOwner],0 ; Is it in use?
|
|
jnz cmsFail ; Yes - cannot use it
|
|
add cx,CB_MEMHDR ; Add the header of next block
|
|
adc dx,0
|
|
add cx,word ptr [cbBlkLen] ; Add the body of the next block
|
|
adc dx,word ptr [cbBlkLen+2];
|
|
mov ax,1 ; Load strategy code
|
|
cmp dx,word ptr [bp - 6] ; Compare available with needed
|
|
ja cmsOK ; Jump if it fits
|
|
cmp cx,word ptr [bp - 4] ;
|
|
jae cmsOK ;
|
|
|
|
; Cannot expand. The max available is in CX&DX
|
|
|
|
cmsFail:
|
|
add sp,6 ; Throw away requested size, and strat
|
|
pop es ; Point to original header
|
|
|
|
cmp byte ptr [bp-8],0 ; Should we check the # of
|
|
jz @f ; available selectors?
|
|
stc
|
|
jmp short cmsExit
|
|
@@:
|
|
call CalculateMaximumSegmentSpace ;Check for enough selectors
|
|
stc ;Flag error
|
|
jmp short cmsExit
|
|
|
|
; Expand will succeed. Strategy number is in ax
|
|
|
|
cmsOK:
|
|
add sp,2 ; discard strategy
|
|
pop dx ; Restore requested size
|
|
pop cx ;
|
|
cms900:
|
|
pop es ; Point to original header
|
|
|
|
cmp byte ptr [bp-8],0 ; Should we check the # of
|
|
jz @f ; available selectors?
|
|
clc
|
|
jmp short cmsExit
|
|
@@:
|
|
call CalculateMaximumSegmentSpace ;Check for enough selectors
|
|
|
|
cmsExit:
|
|
pop bp
|
|
ret
|
|
|
|
CalculateMaximumSpace endp
|
|
|
|
|
|
; -------------------------------------------------------
|
|
;
|
|
;
|
|
; CombineFreeBlocks -- This routine is used when freeing
|
|
; an extended memory block. It will examine the previous
|
|
; and following blocks to see if they are free also, and
|
|
; combine them into a single larger block if so.
|
|
;
|
|
; Input: AX - selector of segment descriptor for the block
|
|
; Output: AX - selector for new free memory block
|
|
; Errors: none
|
|
; Uses: AX, ES modified, all other registers preserved
|
|
;
|
|
; NOTE: This routine may free the segment descriptor for the
|
|
; entry block as part of the process of combining blocks.
|
|
; The original entry value may no longer be used after
|
|
; calling this routine. If access to the block header
|
|
; for the free segment is still needed, you must use
|
|
; the value returned in AX to access it.
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public CombineFreeBlocks
|
|
|
|
CombineFreeBlocks:
|
|
push bx
|
|
push dx
|
|
;
|
|
mov bx,ax ;save entry value in BX
|
|
;
|
|
; Look at the previous block and see if it is free.
|
|
mov es,bx ;look at block header of entry block
|
|
assume es:MEMHDR
|
|
mov es,[selBlkPrev] ;look at block header of previous block
|
|
cmp [selBlkOwner],0 ;is it in use?
|
|
jnz cfrb30 ;if so, continue on
|
|
;
|
|
; The previous memory block is free. We need to combine it with the
|
|
; current one.
|
|
mov ax,bx
|
|
call SpliceBlocks
|
|
mov bx,es
|
|
;
|
|
; Look at the following block and see if it is free.
|
|
cfrb30: mov es,bx ;look at the current lower free block
|
|
assume es:MEMHDR
|
|
mov es,[selBlkNext] ;look at the following block
|
|
cmp [selBlkOwner],0 ;is it in use?
|
|
jnz cfrb90
|
|
;
|
|
; The following memory block is free. We need to combine it with the
|
|
; current one.
|
|
mov ax,es
|
|
mov es,bx
|
|
call SpliceBlocks
|
|
;
|
|
; All done
|
|
cfrb90: mov ax,bx
|
|
pop dx
|
|
pop bx
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
; SpliceBlocks -- This routine is used by CombineFreeBlocks
|
|
; to perform the actual combination of two adjacent free
|
|
; blocks. The space occupied by the upper block is assigned
|
|
; to the lower block, and the upper block is then eliminated.
|
|
;
|
|
; Input: AX - selector to the upper block
|
|
; ES - selector to the lower block
|
|
; Output: none
|
|
; Errors: none
|
|
; Uses: AX, DX modified
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
|
|
SpliceBlocks:
|
|
push ds
|
|
mov ds,ax
|
|
assume ds:NOTHING ;DS points at upper block
|
|
;ES points at lower block
|
|
push ax
|
|
;
|
|
mov dx,word ptr ds:[cbBlkLen]
|
|
mov ax,word ptr ds:[cbBlkLen+2]
|
|
add dx,CB_MEMHDR
|
|
adc ax,0
|
|
add word ptr es:[cbBlkLen],dx
|
|
adc word ptr es:[cbBlkLen+2],ax
|
|
mov ax,ds:[selBlkNext]
|
|
mov es:[selBlkNext],ax
|
|
mov ds,ax ;DS points at block following entry block
|
|
mov ds:[selBlkPrev],es
|
|
;
|
|
pop ax
|
|
pop ds
|
|
|
|
call FreeSelector ;release the segment descriptor for the
|
|
; upper block
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
; FindFreeBlock -- This function will search the extended
|
|
; memory heap looking for a free memory block of at
|
|
; least the requested size.
|
|
;
|
|
; Input: CX - low word of requested block size
|
|
; DX - high word or requested block size
|
|
; Output: AX - selector for the block header of the free block
|
|
; cbHeapBlkMax - size of largest free block found
|
|
; cbHeapFreeSpace - total free space seen
|
|
; Errors: Returns CY set if large enough free block not found.
|
|
; If that happens, then cbHeapBlkMax contains the size of the
|
|
; largest free block, and cbHeapFreeSpace contains the total
|
|
; of all free blocks.
|
|
; Uses: AX modified, all other registers preserved.
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public FindFreeBlock
|
|
|
|
FindFreeBlock:
|
|
push cx
|
|
push dx
|
|
push es
|
|
;
|
|
mov word ptr [cbHeapBlkMax],0
|
|
mov word ptr [cbHeapBlkMax+2],0
|
|
mov word ptr [cbHeapFreeSpace],0
|
|
mov word ptr [cbHeapFreeSpace+2],0
|
|
;
|
|
cmp selHeapStart,0 ;
|
|
jz ffrb80 ; No heap - no allocate - jump
|
|
mov es,selHeapStart ; ES points at the beginning of the heap
|
|
assume es:MEMHDR
|
|
;
|
|
; Is the current memory block free?
|
|
ffrb20:
|
|
cmp selBlkOwner,0 ;if the block isn't free, try the next one
|
|
jnz ffrb26
|
|
;
|
|
; Accumulate size into free space count.
|
|
mov ax,word ptr [cbBlkLen]
|
|
add word ptr [cbHeapFreeSpace],ax
|
|
mov ax,word ptr [cbBlkLen+2]
|
|
adc word ptr [cbHeapFreeSpace+2],ax
|
|
;
|
|
; Update our view of what the largest free block is.
|
|
mov ax,word ptr [cbBlkLen+2]
|
|
cmp ax,word ptr [cbHeapBlkMax+2]
|
|
jc ffrb26
|
|
jnz ffrb22
|
|
mov ax,word ptr [cbBlkLen]
|
|
cmp ax,word ptr [cbHeapBlkMax]
|
|
jc ffrb26
|
|
ffrb22: mov ax,word ptr [cbBlkLen+2]
|
|
mov word ptr [cbHeapBlkMax+2],ax
|
|
mov ax,word ptr [cbBlkLen]
|
|
mov word ptr [cbHeapBlkMax],ax
|
|
;
|
|
; Check the size of this memory block to see if it is large enough.
|
|
ffrb24: cmp dx,word ptr [cbBlkLen+2]
|
|
jc ffrb40
|
|
jnz ffrb26
|
|
cmp cx,word ptr [cbBlkLen]
|
|
jna ffrb40
|
|
;
|
|
; Go to the next block in the heap
|
|
ffrb26:
|
|
cmp selBlkNext,0 ; End of chain?
|
|
jz ffrb80 ; Yes - jump
|
|
mov es,[selBlkNext]
|
|
jmp ffrb20
|
|
;
|
|
; Found a free block that is large enough
|
|
ffrb40: mov ax,es
|
|
clc
|
|
jmp short ffrb90
|
|
;
|
|
; Didn't find one, return error.
|
|
ffrb80: stc
|
|
;
|
|
; All done
|
|
ffrb90: pop es
|
|
pop dx
|
|
pop cx
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
; FreeSpace -- This function is used to find out how
|
|
; much free space there is in the heap, plus that
|
|
; which is potentially available from an XMS driver.
|
|
;
|
|
; Input: None
|
|
; Output: AX:DX -- Total free space
|
|
; BX:CX -- Largest free block
|
|
; Errors: none
|
|
; Uses: AX, all else preserved
|
|
;
|
|
; History:10/09/90 -- earleh wrote it.
|
|
;
|
|
cProc FreeSpace,<NEAR,PUBLIC>,
|
|
cBegin
|
|
|
|
;
|
|
; Call xms to get free memory space
|
|
;
|
|
pmxmssvc 08h
|
|
|
|
;
|
|
; convert to bytes
|
|
;
|
|
mov bx,dx
|
|
mov dx,ax
|
|
mov cx,bx
|
|
shl dx,10
|
|
shr ax,6
|
|
shl cx,10
|
|
shr bx,6
|
|
|
|
;
|
|
; account for heap header
|
|
;
|
|
sub dx,CB_MEMHDR
|
|
sbb ax,0
|
|
sub cx,CB_MEMHDR
|
|
sbb bx,0
|
|
|
|
ret
|
|
cEnd
|
|
|
|
; -------------------------------------------------------
|
|
; SplitBlock -- This function will split the specified
|
|
; memory block into two blocks, with the first one
|
|
; being the specified size, and the second one containing
|
|
; the remaining space.
|
|
;
|
|
; Input: AX - selector of block header for memory block to split
|
|
; CX - low word of requested size
|
|
; DX - high word of requested size
|
|
; Output: none
|
|
; Errors: none
|
|
; Uses: AX, all else preserved
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public SplitBlock
|
|
|
|
SplitBlock:
|
|
push bx
|
|
push cx
|
|
push dx
|
|
push si
|
|
push es
|
|
;
|
|
mov es,ax
|
|
assume es:MEMHDR
|
|
;
|
|
; We are going to need a segment descriptor for the remainder block
|
|
; when we do the split. Make sure that we can allocate the selector
|
|
; now, before we change anything.
|
|
call AllocateSelector
|
|
jnc spbl20 ;
|
|
jmp spbl90 ;get out if error
|
|
spbl20: mov si,ax ;save selector in SI for later
|
|
;
|
|
; Adjust the size of the current block and figure the size of the
|
|
; remainder.
|
|
xchg cx,word ptr [cbBlkLen] ;store the new block length
|
|
xchg dx,word ptr [cbBlkLen+2] ; and get the old block length
|
|
push cx ;Save the original size for recovery
|
|
push dx
|
|
sub cx,word ptr [cbBlkLen] ;compute the amount of space
|
|
sbb dx,word ptr [cbBlkLen+2] ; remaining in the block
|
|
sub cx,CB_MEMHDR ;also account for the new block header
|
|
sbb dx,0
|
|
jc spbl25 ;Jump if not enough memory to split
|
|
jnz spbl30 ;if there is some remaining memory, then
|
|
cmp cx,0 ; we have additional work to do
|
|
jnz spbl30
|
|
;
|
|
; There is no remaining memory. Free the selector that we allocated
|
|
; earlier and then get out.
|
|
spbl25: mov ax,si
|
|
pop dx ;Recover old size
|
|
pop cx
|
|
mov word ptr [cbBlkLen],cx ;restore the old block length
|
|
mov word ptr [cbBlkLen+2],dx
|
|
call FreeSelector
|
|
jmp spbl90
|
|
;
|
|
; We need to create a segment descriptor for the new memory block header
|
|
; for the remainder block.
|
|
spbl30: add sp,4 ;Dispose of unneeded recovery data
|
|
push cx ;save memory block length for later
|
|
push dx
|
|
mov ax,es ;selector of current memory header
|
|
call GetSegmentAddress
|
|
mov cx,CB_MEMHDR - 1
|
|
add dx,word ptr [cbBlkLen] ;bump by size of current block
|
|
adc bx,word ptr [cbBlkLen+2]
|
|
add dx,CB_MEMHDR ;plus size of block header
|
|
adc bx,0
|
|
mov ax,si
|
|
cCall NSetSegmentDscr,<ax,bx,dx,0,cx,STD_DATA>
|
|
pop dx
|
|
pop cx
|
|
;
|
|
; Now, we need to build a new memory block header for the remainder of
|
|
; the original block. CX,DX has the size of the new block.
|
|
push ds
|
|
;
|
|
mov ds,si
|
|
assume ds:NOTHING ;DS points at new block header
|
|
assume es:NOTHING ;ES points at old block header
|
|
xor ax,ax
|
|
mov ds:[fBlkStatus],al
|
|
mov ds:[cselBlkData],al
|
|
mov ds:[selBlkData],ax
|
|
mov ds:[selBlkOwner],ax
|
|
mov ds:[selBlkHdr],ds
|
|
mov word ptr ds:[cbBlkLen],cx
|
|
mov word ptr ds:[cbBlkLen+2],dx
|
|
mov ds:[selBlkPrev],es
|
|
mov ax,es:[selBlkNext]
|
|
mov ds:[selBlkNext],ax
|
|
mov es:[selBlkNext],si
|
|
mov ds,ax ;DS points at following block
|
|
mov ds:[selBlkPrev],si
|
|
cmp ds:[selBlkOwner],0 ;is it in use?
|
|
;
|
|
pop ds
|
|
assume ds:DGROUP
|
|
jnz spbl90 ;Jump if the following block is not free
|
|
;
|
|
; The following memory block is free. We need to combine it with the
|
|
; current one.
|
|
mov es,si
|
|
call SpliceBlocks
|
|
;
|
|
; All done
|
|
spbl90: pop es
|
|
pop si
|
|
pop dx
|
|
pop cx
|
|
pop bx
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
; GetBlockHeader -- This function will return the selector
|
|
; for the block header of the specified memory data
|
|
; block.
|
|
;
|
|
; Input: AX - selector of the data block
|
|
; Output: AX - selector of the block header
|
|
; Errors: returns CY set if the entry selector doesn't point
|
|
; to a valid data block
|
|
; Uses: AX, all other registers preserved
|
|
; Modifies the descriptor for segment SEL_SCR0
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
|
|
GetBlockHeader:
|
|
push bx
|
|
push cx
|
|
push dx
|
|
push es
|
|
|
|
push ax ;save entry value for later
|
|
mov bx,SEL_SCR0 or STD_TBL_RING
|
|
call DupSegmentDscr ;duplicate input descriptor to scratch
|
|
mov ax,bx
|
|
call GetSegmentAddress
|
|
sub dx,CB_MEMHDR ;backup to supposed header
|
|
sbb bx,0
|
|
mov cx,CB_MEMHDR-1 ; has the proper limit!
|
|
cCall NSetSegmentDscr,<ax,bx,dx,0,cx,STD_DATA>
|
|
|
|
mov es,ax
|
|
assume es:MEMHDR
|
|
|
|
pop cx ;recover data block selector
|
|
cmp cx,[selBlkData] ;does the header point back to the
|
|
jz gtbh50 ; data block.
|
|
|
|
stc ;if not, then what were given wasn't a
|
|
jmp short gtbh90 ; selector to a memory block
|
|
|
|
gtbh50: mov ax,[selBlkHdr] ;get the real selector to the header
|
|
|
|
gtbh90: pop es
|
|
pop dx
|
|
pop cx
|
|
pop bx
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
; DisposeBlock -- This routine will free all segment
|
|
; descriptors associated with the specified memory block,
|
|
; and remove the block header from the heap list.
|
|
;
|
|
; Input: AX - selector of block to dispose
|
|
; Output: none
|
|
; Errors: none
|
|
; Uses: All registers preserved
|
|
;
|
|
; NOTE: This routine frees selectors for the specified memory block.
|
|
; If this selector is already in a segment register when this
|
|
; routine is called a GP fault will occur it that segment
|
|
; register is later saved or restored. Also, any references to
|
|
; memory using that segment register might destroy random data
|
|
; in memory.
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public DisposeBlock
|
|
|
|
DisposeBlock:
|
|
push cx
|
|
push si
|
|
push di
|
|
push es
|
|
;
|
|
; Remove the block header from the heap list.
|
|
mov es,ax ;header selector to ES
|
|
mov si,es:[selBlkNext] ;SI points to following block
|
|
mov di,es:[selBlkPrev] ;DI points to previous block
|
|
mov es,di ;ES points to previous block
|
|
mov es:[selBlkNext],si ;previous block points to following block
|
|
mov es,si ;ES points to following block
|
|
mov es:[selBLkPrev],di ;following block points back to prev. block
|
|
;
|
|
; Free any data block descriptors associated with this memory object.
|
|
mov es,ax
|
|
cmp es:[selBlkOwner],0
|
|
jz dspb40
|
|
xor ch,ch
|
|
mov cl,es:[cselBlkData]
|
|
mov ax,es:[selBlkData]
|
|
and ax,SELECTOR_INDEX ;treat as GDT FreeSelectorBlock
|
|
call FreeSelectorBlock
|
|
;
|
|
; Free the descriptor for the block header.
|
|
dspb40: mov ax,es
|
|
pop es
|
|
call FreeSelector
|
|
;
|
|
; All done
|
|
dspb90: pop di
|
|
pop si
|
|
pop cx
|
|
ret
|
|
|
|
; -------------------------------------------------------
|
|
; SetUpDataDescriptors -- This function will initialize
|
|
; all of the data segment descriptors associated with
|
|
; a block. Those that should point to data will be
|
|
; initialized accordingly. Those corresponding to
|
|
; addresses beyond the allocated data will be initialized
|
|
; as not present. If insufficient data segment
|
|
; descriptors have been allocated, an attempt
|
|
; will be made to allocate them. If this fails an error
|
|
; occurs.
|
|
;
|
|
; Input: AX - Selector of the header segment.
|
|
;
|
|
; Output: None
|
|
;
|
|
; Errors: Returns CY set if not enough data segment descriptors
|
|
; are available.
|
|
;
|
|
; Uses: Segment descriptor table is modified. Possibly the
|
|
; data segment count in the header is modified.
|
|
; No registers affected.
|
|
;
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
|
|
public SetUpDataDescriptors
|
|
|
|
SetUpDataDescriptors:
|
|
push es
|
|
push si
|
|
push bx
|
|
push cx
|
|
push dx
|
|
push ax
|
|
|
|
mov es,ax
|
|
mov si,ax ;save header segment for dup
|
|
assume es:MEMHDR
|
|
mov bx,selBlkData ;Starting data selector index
|
|
and bx,SELECTOR_INDEX
|
|
xor cx,cx
|
|
mov cl,cselBlkData ;Load segment count
|
|
inc cx
|
|
mov dx,word ptr es:[cbBlkLen+2] ;Full data segment count
|
|
mov es,selGDT
|
|
assume es:NOTHING
|
|
sudd30:
|
|
or dx,dx ;is this the last segment?
|
|
jnz sudd35
|
|
pop es ;Get the header segment
|
|
push es
|
|
cmp word ptr es:[cbBlkLen],0 ;Test partial length
|
|
mov es,selGDT ;Rebase the global descriptor table
|
|
jnz sudd35 ;Jump if the partial length is 0
|
|
jmp sudd60
|
|
sudd35: loop short sudd40 ;Out of segments?
|
|
xchg bx,ax
|
|
call RemoveFreeDescriptor ;Attempt to get segment
|
|
xchg bx,ax
|
|
jnc sudd37
|
|
jmp sudd80
|
|
sudd37: inc cx
|
|
sudd40: mov ax,si
|
|
call DupSegmentDscr ; replicate the previous seg (in si)
|
|
mov si,bx
|
|
|
|
; Set the DPL of allocated blocks to user DPL
|
|
|
|
ifndef WOW_x86
|
|
mov es:[si].arbSegAccess,STD_DATA
|
|
else
|
|
push ax
|
|
xor ax,ax
|
|
mov ah,es:[si].cbLimitHi386
|
|
or ax,STD_DATA
|
|
cCall NSetSegmentAccess,<si,ax>
|
|
pop ax
|
|
endif
|
|
|
|
; Increment the segment start address past the previous one
|
|
|
|
cmp es:[si].cbLimit,CB_MEMHDR-1 ; Is this the first block?
|
|
jne sudd41 ; No - jump
|
|
ifndef WOW_x86
|
|
add es:[si].adrBaseLow,CB_MEMHDR ; bump segment start to point
|
|
adc es:[si].adrBaseHigh,0 ;past the block header
|
|
else
|
|
push ax
|
|
push dx
|
|
mov ax,es:[si].adrBaseLow
|
|
mov dl,es:[si].adrBaseHigh
|
|
mov dh,es:[si].adrbBaseHi386
|
|
add ax,CB_MEMHDR
|
|
adc dx,0
|
|
cCall NSetSegmentBase,<si,dx,ax>
|
|
pop dx
|
|
pop ax
|
|
endif
|
|
jmp short sudd42
|
|
ifndef WOW_x86
|
|
sudd41: add es:[si].adrBaseHigh,1 ; bump segment start by 64k
|
|
else
|
|
sudd41: push ax
|
|
push dx
|
|
mov ax, es:[si].adrBaseLow
|
|
mov dl, es:[si].adrBaseHigh
|
|
mov dh, es:[si].adrbBaseHi386
|
|
inc dx
|
|
cCall NSetSegmentBase,<si,dx,ax>
|
|
pop dx
|
|
pop ax
|
|
endif
|
|
|
|
; Set the segment length
|
|
|
|
sudd42: add bx,8 ; Offset of next segment descriptor
|
|
or dx,dx ; Was this a partial segment?
|
|
jnz sudd45 ; jump if not
|
|
;
|
|
; We are at the partial (<64k) chunk at the end.
|
|
pop es ;Get the header segment
|
|
push es
|
|
mov dx,word ptr es:[cbBlkLen] ; Segment length
|
|
dec dx ; Last legal offset
|
|
mov es,selGDT
|
|
mov es:[si].cblimit,dx ; Store in segment descriptor
|
|
ifdef WOW_x86
|
|
cCall NSetSegmentLimit,<si>
|
|
endif
|
|
jmp sudd60 ; All valid data segs now exist
|
|
sudd45:
|
|
mov es:[si].cbLimit,0FFFFh ;set segment limit at 64k
|
|
ifdef WOW_x86
|
|
cCall NSetSegmentLimit,<si>
|
|
endif
|
|
dec dx ; On to the next data segment
|
|
jmp sudd30
|
|
;
|
|
; Invalidate remaining segments
|
|
sudd50: mov ax,si
|
|
call DupSegmentDscr ; replicate the previous one and
|
|
mov si,bx
|
|
mov word ptr es:[si].arbSegAccess,0 ; Invalidate the segment
|
|
add bx,8 ; Offset of next segment descriptor
|
|
sudd60: loop sudd50
|
|
;
|
|
; All done
|
|
clc
|
|
jmp short sudd90
|
|
;
|
|
; Allocate of a segment descriptor failed.
|
|
sudd80: pop ax ;Header Segment
|
|
mov es,ax ;
|
|
mov dx,es:selBlkData ;Calculate # segments
|
|
and dx,SELECTOR_INDEX ; successfully allocated
|
|
sub bx,dx
|
|
shr bx,3 ;Succesfully allocated
|
|
mov es:[cselBlkData],bl ;Store new value
|
|
mov dx,bx ;Return max allocatable space
|
|
mov cx,0 ;
|
|
add sp,4 ;Pop redundant stack data
|
|
stc ;Flag error
|
|
jmp short sudd100 ;Join common exit code
|
|
;
|
|
; Tidy up
|
|
sudd90: pop ax ;Header segment
|
|
mov es,ax
|
|
mov dx,es:selBlkData ;Calculate # segments
|
|
and dx,SELECTOR_INDEX
|
|
sub bx,dx
|
|
shr bx,3
|
|
mov es:[cselBlkData],bl ;Store new value
|
|
pop dx
|
|
pop cx
|
|
sudd100:
|
|
pop bx
|
|
pop si
|
|
pop es
|
|
ret
|
|
;
|
|
ifdef MD
|
|
|
|
; -------------------------------------------------------
|
|
; CheckXmemHeap -- This routine will check the integrity
|
|
; of the chain of block headers.
|
|
;
|
|
; Input: NONE
|
|
; Output: None
|
|
; Errors: INT3 If an error is found
|
|
; Uses: All registers preserved
|
|
;
|
|
; NOTE: This routine must be called in protected mode.
|
|
|
|
assume ds:DGROUP,es:NOTHING,ss:NOTHING
|
|
public CheckXmemHeap
|
|
|
|
CheckXmemHeap:
|
|
push bp
|
|
mov bp,sp
|
|
pushf
|
|
push bx
|
|
push cx
|
|
push dx
|
|
push es
|
|
xor cx,cx
|
|
mov dx,cx
|
|
mov bx,selHeapStart ; Load start of chain
|
|
cxmh100:
|
|
or bx,bx ;
|
|
jnz cxmh101
|
|
jmp cxmh200 ;
|
|
cxmh101:
|
|
mov es,bx ;
|
|
assume es:MEMHDR ;
|
|
cmp selBlkHdr,bx ;
|
|
je cxmh110 ;
|
|
int 3
|
|
jmp cxmh200
|
|
;; Debug_Out "CheckXmemHeap: Block header does not point to block header!"
|
|
cxmh110:
|
|
cmp selBlkPrev,dx ;
|
|
je cxmh120 ;
|
|
int 3
|
|
jmp cxmh200
|
|
;; Debug_Out "CheckXmemHeap: Previous block does not point to previous block!"
|
|
cxmh120:
|
|
mov dx,bx ;
|
|
mov bx,selBlkNext ;
|
|
loop cxmh100 ;
|
|
int 3
|
|
;; Debug_Out "CheckXmemHeap: Can't find end of arena chain!"
|
|
cxmh200:
|
|
pop es
|
|
pop dx
|
|
pop cx
|
|
pop bx
|
|
popf
|
|
pop bp
|
|
ret
|
|
endif
|
|
|
|
; -------------------------------------------------------
|
|
; FreeMemByOwner -- This routine frees all of the mem
|
|
; blocks that belong to the specified owner.
|
|
;
|
|
; Input: bx = owner
|
|
; Output: none
|
|
; Uses: ax
|
|
;
|
|
; Note: We have to start at the beginning of the heap
|
|
; after we free a block, because the free may
|
|
; coalesce the heap, and the selector for the
|
|
; next block may no longer be correct. We know we
|
|
; are done when we have traversed the entire heap,
|
|
; and not found a block to free.
|
|
|
|
assume ds:DGROUP, es:nothing, ss:nothing
|
|
public FreeMemByOwner
|
|
|
|
FreeMemByOwner:
|
|
push es
|
|
push cx
|
|
|
|
cmp bx,0 ; owner is free owner??
|
|
je fbo40
|
|
|
|
; First traverse xmem heap
|
|
push selHeapStart
|
|
mov ax,selHiHeapStart
|
|
mov selHeapStart,ax
|
|
|
|
call FreeHiMemByOwnerW
|
|
call FreeLowMemByOwnerW
|
|
pop selHeapStart
|
|
|
|
|
|
fbo40:
|
|
pop cx
|
|
pop es
|
|
ret
|
|
|
|
FreeHiMemByOwnerW:
|
|
fhbow10: mov ax,selHiHeapStart
|
|
fhbow20: cmp ax,0
|
|
je @f
|
|
lar cx, ax ;is this a valid selector?
|
|
jz fhbow25 ;yes, go ahead
|
|
@@:
|
|
ret
|
|
|
|
fhbow25: mov es,ax
|
|
assume es:MEMHDR
|
|
cmp selBlkOwner,bx
|
|
jne fhbow30
|
|
|
|
mov ax,selBlkDAta
|
|
push 0
|
|
pop es
|
|
call FreeXmemBlock
|
|
jmp fhbow10 ; check again.
|
|
|
|
fhbow30: mov ax,selBlkNext ; check next block
|
|
jmp fhbow20
|
|
|
|
FreeLowMemByOwnerW:
|
|
flbow10: mov ax,selLowHeapStart
|
|
flbow20: cmp ax,0
|
|
je @f
|
|
lar cx, ax ;is this a valid selector?
|
|
jz flbow25 ;yes, go ahead
|
|
@@:
|
|
ret
|
|
|
|
flbow25: mov es,ax
|
|
assume es:MEMHDR
|
|
cmp selBlkOwner,bx
|
|
jne flbow30
|
|
|
|
mov ax,selBlkData
|
|
push 0
|
|
pop es
|
|
call FreeLowBlock
|
|
jmp flbow10 ; check again.
|
|
|
|
flbow30: mov ax,selBlkNext ; check next block
|
|
jmp flbow20
|
|
; -------------------------------------------------------
|
|
; -------------------------------------------------------
|
|
; -------------------------------------------------------
|
|
; -------------------------------------------------------
|
|
; -------------------------------------------------------
|
|
|
|
DXPMCODE ends
|
|
;
|
|
;****************************************************************
|
|
end
|