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fhchn.asm
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上传日期：2013-04-11
资源大小：19621k
文件大小：9k
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操作系统开发
开发平台：
Visual C++
- TITLE FHCHN - Far Heap CHAIN & SHELL Support
- PAGE 56,132
- ;***
- ;FHCHN.ASM - Far Heap CHAIN & SHELL for the BASIC 3 Common Runtime
- ;
- ; Copyright (C) Microsoft Corp. 1988.
- ;
- ;*****************************************************************************
- SUBTTL INCLUDES AND DEFINITIONS FOLLOWS
- INCLUDE switch.inc
- INCLUDE rmacros.inc
- USESEG <INIT_CODE> ;Initialization
- USESEG <BR_DATA>
- USESEG <_DATA>
- USESEG <_BSS>
- USESEG <NH_TEXT>
- USESEG <RT_TEXT>
- USESEG <FH_TEXT>
- USESEG <DV_TEXT>
- USESEG <XIB>
- USESEG <XI>
- USESEG <XIE>
- USESEG <BC_SAB>
- USESEG <BC_SA>
- INCLUDE seg.inc
- INCLUDE idmac.inc
- INCLUDE compvect.inc
- INCLUDE messages.inc
- INCLUDE array.inc
- INCLUDE smchain.inc
- INCLUDE oscalls.inc
- INCLUDE addr.inc
- INCLUDE baslibma.inc
- INCLUDE string.inc
- INCLUDE stack2.inc
- externNP B$ERR_FHC ;bad memory block address
- INITIALIZER B$xFHCHNINI ;put B$xFHCHNINI in initializer list
- SUBTTL DATA DEFINITIONS
- sBegin BR_DATA
- externW __acmdseg ;C startup __psp
- sEnd BR_DATA
- sBegin _DATA
- externW b$shli_disp ;Shell initialization dispatch table
- externW b$shlt_disp ;Shell termination dispatch table
- sEnd _DATA
- sBegin _BSS
- externW b$FHDStart ;starting FHD for list
- externB b$FHDULNearData
- externB b$FHDULFarData
- externW b$FHDEnd ;ending FHD for list
- staticW ShellRestore,,1 ;FH growth on shell restoration
- externW b$NH_first ;NHINIT - starting offset of near heap
- externW b$NH_last ;NHINIT - ending offset of near heap
- sEnd _BSS
- sBegin DV_TEXT
- externNP B$NearRet ;for disp vectors in compvect.inc
- sEnd DV_TEXT
- sBegin NH_TEXT
- externNP B$NHMOV ;move near heap
- sEnd NH_TEXT
- sBegin FH_TEXT
- externNP B$FHSelect
- externNP B$FHMemDosCall
- externNP B$FHCompact
- externNP B$FHLowerTop
- externNP B$FHRaiseTop
- externNP B$FHLowerBottom
- externNP B$FHRaiseBottom
- sEnd FH_TEXT
- PAGE
- SUBTTL Far Heap Initialization
- assumes CS,INIT_CODE
- sBegin INIT_CODE
- ;***
- ;B$xFHCHNINI - Far Heap initializer for chain/shell module
- ;PLM B$xFHCHNINI()
- ;
- ;Purpose:
- ; Added with revision [1].
- ; Initializer for chain/shell module of the Far Heap component.
- ; This routine is called by the Crt0 startup before _main is
- ; called. It will update the indirect dispatch tables for the
- ; far heap routines needed by chain/shell. This insures that
- ; the only time these routines are accessed is when this module
- ; is linked into the user program.
- ;
- ;Entry:
- ; None.
- ;
- ;Exit:
- ; Appropriate dispatch vectors filled.
- ;
- ;Uses:
- ; None.
- ;
- ;Exceptions:
- ; None.
- ;****************************************************************************
- cProc B$xFHCHNINI,<FAR>
- cBegin
- ; update SHELL time initialization dispatch address to FHShlIni
- MOV WORD PTR [b$shli_disp].FH_SIVEC,FH_TEXTOFFSET FHShlIni
- ; update SHELL time termination dispatch address to B$FHShlTerm
- MOV WORD PTR [b$shlt_disp].FH_STVEC,FH_TEXTOFFSET B$FHShlTerm
- cEnd
- sEnd INIT_CODE
- sBegin FH_TEXT
- ASSUMES CS, FH_TEXT
- PAGE
- SUBTTL Far Heap CHAIN Support
- ;***
- ; B$FHShlTerm - Pre SHELL "termination" (DOS 3)
- ;
- ;Purpose:
- ; In preparation for the SHELL statement, compress both the
- ; far and near heaps to the lowest memory possible. Note the
- ; shrinkage amount for restoration after the SHELL executes.
- ;Entry:
- ; None
- ;Exit:
- ; ShellRestore - contains amount released.
- ;Uses:
- ; None.
- ;Exceptions:
- ; Fatal error due to far heap inconsistency.
- ;******************************************************************************
- cProc B$FHShlTerm,<PUBLIC,NEAR> ; PUBLIC used to drag in file /O
- cBegin
- MOV AX,0FFFFH ;attempt maximum compression of FH
- CALL B$FHLowerTop ;compress - AX returns amount done
- MOV ShellRestore,AX ;save amount for shell restoration
- cEnd
- ;***
- ; FHShlIni - Post SHELL memory recovery (DOS 3)
- ;
- ;Purpose:
- ; After the SHELL statement has executed, grow the far heap to
- ; its previous size. Grow the near heap to its maximum amount.
- ;Entry:
- ; ShellRestore - contains amout of memory to try to recover
- ;Exit:
- ; None.
- ;Uses:
- ; None.
- ;Exceptions:
- ; Fatal error due to far heap inconsistency.
- ;******************************************************************************
- cProc FHShlIni,<NEAR>
- cBegin
- MOV AX,ShellRestore ;recall amount of compression before SHELL
- CALL B$FHRaiseTop ;raise the size of FH to preSHELL level
- CALL B$FHRaiseBottom ;raise the near heap to its maximum level
- cEnd
- ;***
- ; B$FHClean - Far heap clean for CHAIN statement (DOS 3 & 5 RTM)
- ;
- ;Purpose:
- ; Far heap setup for CHAIN statement. Cleans FH of entries
- ; whose descriptors are not in COMMON.
- ;Entry:
- ; None.
- ;Exit:
- ; None.
- ;Uses:
- ; None.
- ;Exceptions:
- ; None.
- ;******************************************************************************
- ;***
- ; FHClean - Clean FH of Non-COMMON entries (DOS 3 & 5 RTM)
- ;
- ;Purpose:
- ; Clean far heap of entries whose descriptors are not
- ; within COMMON.
- ; If QBI, don't deallocate b$FHDULNearData and b$FHDULFarData. These
- ; two contain clean images of the user-lib preinited data (if UL loaded)
- ; that are used to reinitialize the UL Data after CHAIN or RUN.
- ;
- ;Entry:
- ; SI - ptr to FH descriptor to check
- ;Exit:
- ; AX - 0 means don't deallocate entry
- ;Uses:
- ; None.
- ;Exceptions:
- ; None.
- ;******************************************************************************
- ;***
- ; B$FHPostChain - Far heap recovery for CHAIN statement (DOS 3 RTM)
- ;
- ;Purpose:
- ; Finish DGROUP reconstruction after new program has been
- ; chained. The far and near heap have been recleaned if
- ; COMMON truncation occurred.
- ;Entry:
- ; BX = new starting offset of near heap.
- ; CX = DGROUP saved area segment.
- ; DS = ES = new program DGROUP segment.
- ;Exit:
- ; None.
- ;Uses:
- ; None.
- ;Exceptions:
- ; Error if near heap or far heap inconsistency.
- ;******************************************************************************
- ;***
- ;B$FHAdjPreChain - Adjust FH selectors and Give to Child process (DOS 5 RTM)
- ;
- ;Purpose:
- ; This routine is used for DOS 5 CHAIN. It will give all far
- ; heap segments to the child process and adjust the descriptor chain.
- ;Entry:
- ; CX = Child process ID
- ;Exit:
- ; AX = DGROUP pointer to first FH descriptor in descriptor chain.
- ;Uses:
- ; None.
- ;Exceptions:
- ; None.
- ;*****************************************************************************
- ;***
- ;FHGiveSeg - give FH segment to child process (DOS 5 RTM)
- ;
- ;Purpose:
- ; This routine is called once for each descriptor in the far heap
- ; descriptor chain. It will give the selector contained in the
- ; descriptor to the chained process and update the selector in
- ; the FH descriptor.
- ;Entry:
- ; CX = Child process ID
- ; SI = DGROUP offset of FH descriptor
- ;Exit:
- ; AX = flag specifing whether or not to deallocate this entry
- ; 0 - means don't deallocate
- ;Uses:
- ; Per Convention.
- ;Preserves:
- ; CX,
- ;Exceptions:
- ; None.
- ;******************************************************************************
- ;***
- ;B$FHAdjPostChain - Adjust FH selectors after CHAIN (DOS 5 RTM)
- ;
- ;Purpose:
- ; This routine is used for DOS 5 CHAIN. It will adjust all far
- ; heap descriptors in the descriptor chain, deallocing any entries
- ; truncated by the new COMMON bounds.
- ;Entry:
- ; AX = Shared memory handle
- ;Exit:
- ; None.
- ;Uses:
- ; Per Convention.
- ;Exceptions:
- ; None.
- ;*****************************************************************************
- assumes ES,DGROUP
- ;***
- ;FHClean5 - Clean truncated COMMON FH entries (DOS 5 RTM)
- ;
- ;Purpose:
- ; This routine is used for DOS 5 CHAIN. It deallocates any far
- ; entries with descriptors that are truncated by the new COMMON
- ; boundaries. The descriptors for these entries are removed
- ; from the descriptor chain.
- ;Entry:
- ; BX - size of new COMMON
- ; DS - shared memory segment
- ; ES - DGROUP
- ; SI - Descriptor to check for cleaning
- ;Exit:
- ; AX - 0 means don't deallocate entry
- ;Uses:
- ; Per Convention.
- ;Preserves:
- ; BX,CX
- ;Exceptions:
- ; None.
- ;******************************************************************************
- ;***
- ; B$FHPreChain - Prepare far heap (and DGROUP) for CHAIN (DOS 3 RTM)
- ;
- ;Purpose:
- ; Prepare the DGROUP for chaining. This routine is entered
- ; with both near and far heaps cleaned (nonCOMMON entries
- ; removed) and the new stack defined. The data segment is
- ; truncated to RTM data, COMMON statics, a 200H-byte stack,
- ; and compressed near and far heaps. This data is placed in
- ; high memory and the DS is adjusted.
- ;Entry:
- ; AX - new DGROUP offset of near heap.
- ;Exit:
- ; DS - new high data segment location.
- ;Uses:
- ; AX, BX, CX, DX, SI, DI.
- ;Exceptions:
- ; Errors due to near or far heap inconsistency.
- ;******************************************************************************
- sEnd FH_TEXT
- END
