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TITLE HANDLE - Handle Table Manager
include kernel.inc
; This code assumes the following conditions;errnz <lhe_address>
DataBegin
;externW <pGlobalHeap,hGlobalHeap>
DataEnd
sBegin CODEassumes CS,CODE
; These are all of the internal subroutines defined in this source file.;; PUBLIC halloc, lhdref, henum
;-----------------------------------------------------------------------;; halloc ;; ;; Allocates a local handle for a block. ;; ;; Arguments: ;; AX = block that needs a handle ;; DS:DI = address of local arena infomation structure ;; ;; Returns: ;; AX,BX,CX = handle for that block ;; DX preserved ;; ;; Error Returns: ;; AX = 0 if no handles available ;; DX = original AX ;; ;; Registers Preserved: ;; DI,SI,DS,ES ;; ;; Registers Destroyed: ;; ;; Calls: ;; nothing ;; ;; History: ;; ;; Wed Oct 01, 1986 05:44:44p -by- David N. Weise [davidw] ;; Added this nifty comment block. ;;-----------------------------------------------------------------------;
cProc halloc,<PUBLIC,NEAR>cBegin nogen mov bx,[di].hi_hfree or bx,bx jnz have_a_handle push ax push dx mov cx,[di].hi_hdelta jcxz hafail push si push es call [di].hi_hexpand pop es pop si jcxz hafail mov bx,ax pop dx pop axhave_a_handle: xor cx,cx errnz <lhe_flags - he_flags> mov word ptr [bx].lhe_flags,cx ; Zero lock count and flags errnz <lhe_count-lhe_flags-1> errnz <lhe_link - he_link> xchg [bx].lhe_link,ax ; Remove handle from head of chain errnz <lhe_address-lhe_link> ; and store true address of object mov [di].hi_hfree,ax ; Update head of handle free list mov ax,bx ; Return handle to caller mov cx,ax ret
hafail: xor ax,ax pop dx ; Flush stack pop dx ; Return original AX in DX ret ; return errorcEnd nogen
;-----------------------------------------------------------------------;; lhfree ;; ;; Frees the given local handle and returns a handle to the freelist. ;; ;; Arguments: ;; SI = handle to free ;; ;; Returns: ;; AX = 0 if valid handle ;; ;; Error Returns: ;; AX = -1 if handle already free ;; ;; Registers Preserved: ;; ;; Registers Destroyed: ;; ;; Calls: ;; nothing ;; ;; History: ;; ;; Tue Oct 14, 1986 04:14:25p -by- David N. Weise [davidw] ;; Added this nifty comment block. ;;-----------------------------------------------------------------------;
cProc lhfree,<PUBLIC,NEAR>cBegin nogen or si,si ; Ignore zero handles jz hf1 mov ax,HE_FREEHANDLE ; Mark handle as free xchg word ptr [si].lhe_flags,ax errnz <2-lhe_flags> inc ax ; Already free? jz hf2 ; Yes, return error errnz <1+HE_FREEHANDLE> mov ax,si ; Push handle on head of freelist xchg [di].hi_hfree,ax mov [si].lhe_link,axhf1: xor ax,ax ; Return zero rethf2: dec ax retcEnd nogen
;-----------------------------------------------------------------------;; lhdref ;; ;; Dereferences a local handle. ;; ;; Arguments: ;; SI = handle ;; ;; Returns: ;; AX = address of client data or zero for discarded objects ;; CH = lock count ;; CL = zero or LHE_DISCARDED flag ;; ZF = 1 AX = 0 and CL != 0 ;; ;; Error Returns: ;; ;; Registers Preserved: ;; ;; Registers Destroyed: ;; ;; Calls: ;; nothing ;; ;; History: ;; ;; Tue Oct 14, 1986 04:16:49p -by- David N. Weise [davidw] ;; Added this nifty comment block. ;;-----------------------------------------------------------------------;
cProc lhdref,<PUBLIC,NEAR>cBegin nogen xor ax,ax mov cx,word ptr [si].lhe_flags errnz <2-lhe_flags> errnz <3-lhe_count> inc cx jz lhdref1 errnz <1+LHE_FREEHANDLE> dec cx and cl,LHE_DISCARDED jnz lhdref1 mov ax,[si].lhe_addresslhdref1: or ax,ax retcEnd nogen
;-----------------------------------------------------------------------;; henum ;; ;; Enumerates the allocated handles in the local handle table with the ;; specified discard level. ;; ;; Arguments: ;; SI = zero first time called. Otherwise contains a pointer ;; to the last handle returned. ;; CX = #handles remaining. Zero first time called. ;; DI = address of local arena information structure. ;; ;; Returns: ;; SI = address of handle table entry ;; CX = #handles remaining, including the one returned. ;; ZF = 1 if SI = 0 and no more handle table entries. ;; ;; Error Returns: ;; ;; Registers Preserved: ;; ;; Registers Destroyed: ;; AX ;; ;; Calls: ;; nothing ;; ;; History: ;; ;; Tue Oct 14, 1986 04:19:15p -by- David N. Weise [davidw] ;; Added this nifty comment block. ;;-----------------------------------------------------------------------;
cProc henum,<PUBLIC,NEAR>cBegin nogen or si,si ; Beginning of enumeration? jnz lcdhenext ; No, return next handle mov ax,[di].hi_htable ; Yes, start with last handle table block
lcdhtloop: mov si,ax ; SI = address of handle table block or si,si ; Any more handle table blocks? jz lcdheall ; No, return zero lodsw ; Get # handles in this block errnz ht_count mov cx,ax ; into CXlcdheloop: ; Loop to process each handle table entry mov ax,word ptr [si].lhe_flags errnz <lhe_flags - he_flags> errnz <2-lhe_flags> errnz <3-lhe_count>
inc ax ; Free handle? jz lcdhenext ; Yes, skip this handle errnz <1+LHE_FREEHANDLE> errnz <LHE_FREEHANDLE - HE_FREEHANDLE > dec ax
cmp [di].hi_dislevel,0 ; Enumerating all allocated handles? je lcdheall ; Yes, return this handle
test al,LHE_DISCARDED ; No, handle already discarded? jnz lcdhenext ; Yes, skip this handle
and al,LHE_DISCARDABLE ; Test if DISCARDABLE cmp [di].hi_dislevel,al ; at the current discard level jne lcdhenext ; No, skip this handle
or ah,ah ; Is handle locked? jnz lcdhenext ; Yes, skip this handle
lcdheall: or si,si ; No, then return handle to caller ret ; with Z flag clear
lcdhenext: lea si,[si].SIZE LocalHandleEntry ; Point to next handle table entry errnz <LocalHandleEntry - HandleEntry> loop lcdheloop ; Process next handle table entry lodsw ; end of this block, go to next jmp lcdhtloopcEnd nogen
sEnd CODE
end
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