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TITLE GLRU - Primitives for LRU management
.xlistinclude kernel.incinclude newexe.incinclude tdb.incinclude protect.inc.list
DataBegin
;externB EMSSwapDepthexternB Kernel_InDOSexternB Kernel_flags;externW curTDBexternW loadTDBexternW pGlobalHeap;externW hExeSweep
DataEnd
sBegin CODEassumes CS,CODE
externW gdtdscexternNP GetAccessWordexternNP DPMIProc
;-----------------------------------------------------------------------;; lrusweep ;; ;; Searches all of the exe headers in the system for segments that have ;; been accessed since the last time through. For each segment found ;; its referenced byte is reset and that segment is moved to the top ;; of the lru chain. This routine is called (default) every 4 timer ;; ticks from the int 8 handler. ;; ;; Arguments: ;; none ;; ;; Returns: ;; nothing ;; ;; Error Returns: ;; ;; Registers Preserved: ;; DX,DI,SI,DS ;; ;; Registers Destroyed: ;; AX,BX,CX,ES ;; ;; Calls: ;; glrutop ;; ;; History: ;; ;; Tue Apr 21, 1987 06:22:41p -by- David N. Weise [davidw] ;; Added the check for discarded segments. ;; ;; Wed Apr 08, 1987 11:00:59a -by- David N. Weise [davidw] ;; Made it clear only the curTask's private handle table. ;; ;; Wed Feb 18, 1987 08:13:35p -by- David N. Weise [davidw] ;; Added the sweeping of the private handle tables. ;; ;; Tue Feb 10, 1987 02:11:40a -by- David N. Weise [davidw] ;; Added this nifty comment block. ;;-----------------------------------------------------------------------;
cProc lrusweep,<PUBLIC,FAR>cBegin nogen
push dx push di push si push ds xor di,di SetKernelDS cmp kernel_InDOS,0 ; SMARTDrive and EMS may be present jnz dont_do_it ; => disk buffers over the code segs cmp di,loadTDB ; Ignore interrupt if loading task jnz dont_do_it mov ds,pGlobalHeap UnSetKernelDS cmp di,ds:[di].gi_lrulock ; Ignore interrupt if inside memory jz do_it ; managerdont_do_it: jmps sweepdonedo_it:
mov cx, ds:[di].gi_lrucount jcxz stuff_it mov si, ds:[di].gi_lruchain
push bx push ds
;; For WOW dpmi will update the ACCESSED bits from the real LDT in NT on timer ticks;; So it will not be totally accurate but will be accurate enough. mattfe apr16 92
mov ds, gdtdsc ; Go grab it out of the LDTsweep_loop: mov es, si mov si, es:[di].ga_lrunext mov bx, es:[di].ga_handle
sel_check bl
if KDEBUG test ds:[bx].dsc_hlimit, DSC_DISCARDABLE jnz sweep_ok INT3_WARNsweep_ok:endif test ds:[bx].dsc_access, DSC_ACCESSED ; Segment accessed? jz sweep_nextifdef WOW push cx xor cx,cx mov cl, ds:[bx].dsc_access and cx, not DSC_ACCESSED DPMICALL 0009h pop cx jnc @f INT3_WARN@@:else and ds:[bx].dsc_access, not DSC_ACCESSEDendif ; WOW
pop ds call glrutop push ds mov ds, gdtdscsweep_next: loop sweep_loop pop ds pop bx
stuff_it:
sweepdone: pop ds pop si pop di pop dx retcEnd nogen
;; Entry:; DI == 0; DS:SI.gi_lruchain -> head of list; ES:0 -> arena header of object to insert; DX = 0 => insert at head of list; !=0 => insert at tail of list;; Exit:; BX,DX destroyed;cProc LRUInsert,<PUBLIC,NEAR>cBegin nogen inc ds:[si].gi_lrucount ; Increment count of LRU entries mov bx,ds:[si].gi_lruchain ; BX = head of list or dx,dx ; Inserting at head of chain? jnz lruins0 ; No, tail so dont update head mov ds:[si].gi_lruchain,es ; Yes, make new one the new headlruins0: or bx,bx ; List empty? jnz lruins1 mov es:[di].ga_lruprev,es ; Yes, make circular mov es:[di].ga_lrunext,es mov ds:[si].gi_lruchain,es retlruins1: push es ; Save ES push bx ; ES = insertion point mov bx,es ; BX = new mov dx,es ; DX = new pop es xchg es:[di].ga_lruprev,bx mov es,bx xchg es:[di].ga_lrunext,dx pop es mov es:[di].ga_lruprev,bx mov es:[di].ga_lrunext,dx retcEnd nogen
;; Entry:; DI == 0; DS:SI.gi_lruchain -> head of list; ES:0 -> arena header of object to insert;; Exit:; BX,DX destroyed;;cProc LRUDelete,<PUBLIC,NEAR>cBegin nogen
;; This is basically a consistency check, in case we don't fix; GlobalRealloc() for 3.1.; push ax mov ax,es:[di].ga_lrunext or ax,es:[di].ga_lruprev pop ax
jz lrudel_ret
dec ds:[si].gi_lrucount ; Decrement count of LRU entries jnz lrudel0 mov ds:[si].gi_lruchain,di ; List empty, zero LRU chain. mov es:[di].ga_lruprev,di ; Zero pointers in deleted object mov es:[di].ga_lrunext,di retlrudel0: mov dx,es cmp ds:[si].gi_lruchain,dx ; Are we deleting the head? jne lrudel1 mov dx,es:[di].ga_lrunext mov ds:[si].gi_lruchain,dx ; Yes, make it point to the next onelrudel1: xor bx,bx ; Zero pointers in deleted object xchg es:[di].ga_lrunext,bx
xor dx,dx xchg es:[di].ga_lruprev,dx push es mov es,dx mov es:[di].ga_lrunext,bx mov es,bx mov es:[di].ga_lruprev,dx pop eslrudel_ret: retcEnd nogen
;; glruSetup;; INPUT: ES -> arena header; DI = 0;; OUTPUT: ZF set: block is not on LRU list; ZF clear:; SI = 0; ;cProc glruSetup,<PUBLIC,NEAR>cBegin nogen mov bx,es:[di].ga_handle or bx,bx jz gsdone push ax cCall GetAccessWord,<bx> test ah, DSC_DISCARDABLE pop ax jz gsdone ; not a discardable object xor si,si or sp,spgsdone: retcEnd nogen
;-----------------------------------------------------------------------;; glrutop ;; ;; Moves a discardable object to the head of the LRU chain. ;; ;; Arguments: ;; DS:DI = address of global heap info ;; ES:DI = global arena of moveable object ;; ;; Returns: ;; Updated LRU chain ;; ;; Error Returns: ;; ;; Registers Preserved: ;; CX,DX,SI,DS,ES ;; ;; Registers Destroyed: ;; ;; Calls: ;; ;; History: ;; ;; Wed Feb 18, 1987 08:30:45p -by- David N. Weise [davidw] ;; Added support for EMS. ;; ;; Mon Oct 27, 1986 04:20:10p -by- David N. Weise [davidw] ;; Rewrote it to eliminate the handle table as intermediary. ;;-----------------------------------------------------------------------;
cProc glrutop,<PUBLIC,NEAR>cBegin nogen push bx push dx push si call glruSetup jz glrutop1
call LRUDelete xor dx,dx ; DX == 0 means insert at head call LRUInsertglrutop1: pop si pop dx pop bxif KDEBUG call check_lru_listendif retcEnd nogen
;-----------------------------------------------------------------------;; glrubot ;; ;; Moves a discardable object to the tail of the LRU chain. ;; ;; Arguments: ;; DS:DI = address of global heap info ;; ES:DI = global arena of moveable object ;; ;; Returns: ;; Updated LRU chain ;; ;; Error Returns: ;; ;; Registers Preserved: ;; CX,DX,SI,DS,ES ;; ;; Registers Destroyed: ;; ;; Calls: ;; ;; History: ;; ;; Wed Feb 18, 1987 08:30:45p -by- David N. Weise [davidw] ;; Added support for EMS. ;; ;; Mon Oct 27, 1986 04:20:10p -by- David N. Weise [davidw] ;; Rewrote it to eliminate the handle table as intermediary. ;;-----------------------------------------------------------------------;
cProc glrubot,<PUBLIC,NEAR>cBegin nogen push bx push dx push si call glruSetup jz glrubot1
call LRUDelete mov dx,sp ; DX != 0 means insert at tail call LRUInsertglrubot1: pop si pop dx pop bxif KDEBUG call check_lru_listendif retcEnd nogen
;-----------------------------------------------------------------------;; glruadd ;; ;; Adds a discardable object to the head of the LRU chain. ;; ;; Arguments: ;; DS:DI = address of global heap info ;; ES:DI = arena header of object ;; ;; Returns: ;; Updated LRU chain ;; ;; Error Returns: ;; ;; Registers Preserved: ;; AX,BX,CX,DX,DI,SI,DS ;; ;; Registers Destroyed: ;; none ;; ;; Calls: ;; nothing ;; ;; History: ;; ;; Wed Feb 18, 1987 08:30:45p -by- David N. Weise [davidw] ;; Added support for EMS. ;; ;; Mon Oct 27, 1986 04:23:35p -by- David N. Weise [davidw] ;; Rewrote it to eliminate the handle table as intermediary. ;;-----------------------------------------------------------------------;
cProc glruadd,<PUBLIC,NEAR>cBegin nogen push bx push dx push si
call glruSetup jz glruadd1
xor dx,dx ; DX == 0 means insert at head call LRUInsertglruadd1: pop si pop dx pop bxif KDEBUG call check_lru_listendif retcEnd nogen
;-----------------------------------------------------------------------;; glrudel ;; ;; Removes a discardable object from the LRU chain. ;; ;; Arguments: ;; ES:DI = arena header of object ;; DS:DI = address of global heap info ;; ;; Returns: ;; Nothing. ;; ;; Error Returns: ;; ;; Registers Preserved: ;; All ;; ;; Registers Destroyed: ;; ;; Calls: ;; ;; History: ;; ;; Wed Feb 18, 1987 08:30:45p -by- David N. Weise [davidw] ;; Added support for EMS. ;; ;; Mon Oct 27, 1986 04:36:49p -by- David N. Weise [davidw] ;; Rewrote it to eliminate the handle table as intermediary. ;;-----------------------------------------------------------------------;
cProc glrudel,<PUBLIC,NEAR>cBegin nogen push bx push dx push si
call glruSetup jz glrudel1
call LRUDeleteglrudel1: pop si pop dx pop bxif KDEBUG call check_lru_listendif retcEnd nogen
if KDEBUG
;-----------------------------------------------------------------------;; check_lru_list ;; ;; Checks the glru list for consistency. ;; ;; Arguments: ;; nothing ;; ;; Returns: ;; ;; Error Returns: ;; ;; Registers Preserved: ;; All ;; ;; Registers Destroyed: ;; ;; Calls: ;; nothing ;; ;; History: ;; ;; Wed Feb 18, 1987 08:30:45p -by- David N. Weise [davidw] ;; Added support for EMS. ;; ;; Wed Oct 29, 1986 10:13:42a -by- David N. Weise [davidw] ;; Wrote it. ;;-----------------------------------------------------------------------;
cProc check_lru_list,<PUBLIC,NEAR>
cBegin nogen
push ds SetKernelDS test Kernel_flags,kf_check_free jnz check_lru_too jmps cll_retcheck_lru_too: push ax push bx push cx push dx push es mov ds,pGlobalHeap UnSetKernelDS xor bx,bxdo_it_again: mov ax,[bx].gi_lruchain mov cx,[bx].gi_lrucount ; without ems gi_alt_count is 0 or cx,cx jnz short_relative_jumps jmps all_doneshort_relative_jumps: push ds push bx mov es,axcheck_chain_loop: mov ds,es:[di].ga_lruprev mov es,es:[di].ga_lrunext cmp ds:[di].ga_lrunext,ax jz prev_okay mov bx, ax kerror 0FFh,<lru: prev bad>,ds,bx mov ax, bxprev_okay: cmp es:[di].ga_lruprev,ax jz next_okay mov bx, ax kerror 0FFh,<lru: next bad>,bx,esnext_okay: mov ax,es loop check_chain_loop pop bx pop ds cmp [bx].gi_lruchain,ax jz all_done mov cx, ax kerror 0FFh,<lru: count bad>,cx,[bx].gi_lrucountall_done: or bx,bx jnz really_done mov bx,gi_alt_lruchain - gi_lruchain jmp do_it_againreally_done: pop es pop dx pop cx pop bx pop axcll_ret: pop ds ret
cEnd nogen
endif
sEnd CODE
end
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