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Assembly Source File | 1989-04-18 | 26.0 KB | 1,122 lines

page ,132 comment ! * server extension version of c-tree server * terminate/stay resident asm lang support * * This program is the CONFIDENTIAL and PROPRIETARY property * of FairCom(R) Corporation. Any unauthorized use, reproduction or * transfer of this program is strictly prohibited. * * Copyright (c) 1987, 1988, 1989 FairCom Corporation * (Subject to limited distribution and * restricted disclosure only.) * *** ALL RIGHTS RESERVED *** * * 4006 West Broadway * Columbia, MO 65203 * * * c-tree(R) Version 4.3 * Release C * February 7, 1989 17:30 * ! include asm.inc ;-------------------------------------------------------------------- ;configuration control ;-------------------------------------------------------------------- ;note: the same source module can be used for any C memory module ;(with appropiate 'far' modifiers). however it is recommended to ;assemble with a define (/D on the masm line) of one of the ;following: SMALL or COMPACT or MEDIUM or LARGE ;example: masm ctstsr /ml /DCOMPACT; ;-------------------------------------------------------------------- ;comment out next to use dos default of 20 file max FID_TABLE_SZ = 255 ;up to 255 files open ;-------------------------------------------------------------------- ; SMB (Server Message Block) ;-------------------------------------------------------------------- ; sm_res is the field used to hold the server extension name (8 chars) ; this verifies that the SMB is actually for this extension ; the values above are recommended. To include data in the packet: ; starting at sm_vwv: ; dw len_of_data + 3 ; length of byte area ; db 5 ; gen purpose byte data follows ; dw len_of_data ; len of gen purpose byte data ; db len_of_data dup (?) ; the actual data ; ; that last area contains params used by srvx process. This includes ; command code etc. Srvx will put its result here, subject to ; maximum len restriction (srvx_smbmax) Srvx should also put a ; 0 in smb_err and smb_errclass. Any real errors should be in a field ; inside the gen purpose byte data. If a user sends request to server ; where srvx is not installed, server will return smb_errclass = 0xff. ;-------------------------------------------------------------------- SMB struc sm_id db 0ffh,'SMB' ; 00 verification string sm_cmd db 0ffh ; 04 command code sm_errclass db 0 ; 05 error class (DOS, Server, Hardware) sm_err24type db 0ffh ; 06 int 24 AH code sm_err dw 0 ; 07 error code sm_reb db 0 ; 09 nu sm_res dw 7 dup (?) ; 0a nu (*** SEE NOTE) sm_tid dw 0 ; 18 tree ID sm_pid dw 0 ;(or psp) ; 1a process ID (psp) sm_uid dw 0 ; 1c user ID sm_mid dw 0 ; 1e mux ID sm_wct db 0 ; 20 word parameter count sm_vwv dw ? ;see note ; 21 1st word param or begin of byte area SMB ends ;-------------------------------------------------------------------- ; program segment prefix ;-------------------------------------------------------------------- ;-------------------------------------------------------------------- PSP struc pp_int20 dw ? ;+00 exit instruction pp_mtop dw ? ; 02 paragraph past end of mem pp_4 db ? ; 04 pp_cpmcall db ? ; 05 long call opcode pp_cpmmtop dw ? ; 06 long call oprand adj to look like mtop pp_cpmcallseg dw ? ; 08 rest of long call pp_i22term dd ? ; 0a exit to parent addr pp_i23ctlcp dd ? ; 0e ctl-c trap of parent pp_i24cerrp dd ? ; 12 critical err trap of parent pp_parent dw ? ; 16 psp of parent pp_fidtbl db 20 dup (?) ; 18 file id table pp_envseg dw ? ; 2c seg of environment pp_spsave dw ? ; 2e sp save while in dos or execing child pp_sssave dw ? ; 30 ss save " pp_fidtbllen dw ? ; 32 length of fidtbl pp_fidtblptr dd ? ; 34 ptr to fidtbl pp_shr0 dw ? ; 38 set to ffff (used by share.exe) pp_shr1 dw ? ; 3a set to ffff (used by share.exe) db 14h dup (?) ; 3c pp_call50 dw ? ; 50 old convention dos entry pp_call50ret db ? ; 52 db 09h dup (?) ; 53 pp_fcb0 db 16 dup (?) ; 5c pp_fcb1 db 16 dup (?) ; 6c db 4 dup (?) ; 7c pp_cmdtail db 128 dup (?) ; 80 PSP ends ;-------------------------------------------------------------------- ;DOSSTATE structure ;-------------------------------------------------------------------- ; msdos 3.x user context area - everything except current directorys ; the address of this table is obtained with DOS 5d06h call: ; in: ax = 5d06h ; out: ds:si = addr of context data ; dx = len of context data when in_dos flag clear ; cx = len of context data when in_dos flag set ; (struc of this small context is shown below) ;-------------------------------------------------------------------- DOSSTATE struc dst_in_i24 db ? ;00 dos is in int 24 counting flag dst_in_dos db ? ;01 dos is in use counting flag dst_wpe_drv db ? ;02 drive number of write prot error dst_errloc db ? ;03 extended error locus dst_err dw ? ;04 extended error dst_erract db ? ;06 extended error suggested action dst_errclass db ? ;07 extended error class dst_errvol dd ? ;08 extended error volume label ptr dst_dta dd ? ;0c data transfer address dst_psp dw ? ;10 program segment prefix dst_i23_sp dw ? ;12 sp save during int 23 dst_retcode dw ? ;14 dos return code dst_defdrv db ? ;16 default drive dst_breakon db ? ;17 check for ctl-break on/off flag ;18h sizeof dosstate DOSSTATE ends ;--------------------------------------------------------------------- ; DATA ;--------------------------------------------------------------------- ; DSEG extrn __aintdiv:dword ;dos's div exception vector ptr that ;was saved by c-runtime init code MAXSEG = 20 ;size of _abrktb extrn __abrktb:word ;crt (c runtime) table of blocks ;alloc'd from dos extrn __asegds:word ;crt heaprec for malloc in DGROUP extrn __asizds:word ;crt size of DGROUP extrn __psp:word ;crt addr of program seg prefix SXEVinit = 1 SXEVlusmb = 2 SXEVrusmb = 3 SXEVludis = 4 SXEVrudis = 5 public _srvx_smb, _srvx_ncb, _srvx_ses, _srvx_smbmax public _srvx_eventcode even _srvx_smb dd ? ;ptr to smb, ref'd by main code _srvx_ncb dd ? ;ptr to ncb _srvx_ses dw ? ;session number (0 if local user) _srvx_smbmax dw ? ;max len of response smb _srvx_eventcode dw SXEVinit CSEG assume ds:nothing ; NOTE: all data beyond this point is in code segment ;this is the layout of context data saved for both the user and the ;srvx programs. CONTEXT struc cx_i1b dd ? ;int 1b vector (kbd break) cx_i23 dd ? ;int 23 vector (dos ^C) cx_i24 dd ? ;int 24 vector (dos critical error) cx_dost db (size DOSSTATE) dup (?) ;dos variables cx_spare db 20 dup (?) ; CONTEXT ends ifdef DEBUG public u_ctxt, x_ctxt endif even u_ctxt CONTEXT <> ;save area for user context even x_ctxt CONTEXT <> ; for our context ;the program name is set in srvx_init(). It is compared against ;signature in SMB blocks. ifdef DEBUG public srvx_name endif srvx_name db 8 dup (' ') ;name of srvx process ;fixed up user's stack for first call to srvx_wait() ;this will go to code that does an int 21 with ax = term, stay resident ifdef DEBUG public init_ustk, task_memsize endif even dw 64 dup (?) ;slack init_ustk dw 0 ;bx dw 0 ;cx task_memsize dw ? ;dx dw 0 ;si dw 0 ;di dw 0 ;bp dw seg _TEXT ;ds dw seg _TEXT ;es dw OTX go_tsr ;ret ;end of stack ;original vectors for interrupts we patch ifdef DEBUG public i2f_passon, upost_passon, i21_passon endif even i2f_passon dd ? ;continue for mux int intercept upost_passon dd ? ;server extension intercept i21_passon dd ? ;continue for int 21 intercept ;sp saves for context switches ifdef DEBUG public u_sp,u_ss,x_sp,x_ss;for debug endif even u_sp dw OTX init_ustk ;user sp save when in srvx context u_ss dw seg _TEXT x_sp dw ? ;sp save when in user context x_ss dw ? ifdef DEBUG public srvx_waiting, srvx_lock, srvx_mid, srvx_killed endif srvx_waiting db 0 ;flags blocked thread pending srvx_lock db 0 ;0-not in srvx, 1-in srvx, called by ; server, 2-in srvx, called by local ; user (via int 2f) srvx_mid db 0 ;mux id (int 2f, ah value noticed by us) srvx_killed db 0 ;set if server terminates ifdef DEBUG public dos_state, dctx_szsmall, dctx_szlarge endif even dos_state dd ? ;pointer to dos variables dctx_szsmall dw ? ;size of dos variables for context sw. dctx_szlarge dw ? ;size of dos variables for context sw. ; typically some 2k bytes (not used) ; ;replacement file-id so dos can open more than 20 files ; ifdef FID_TABLE_SZ ifdef DEBUG public fid_table endif even fid_table db FID_TABLE_SZ dup (0ffh) endif ;debug vars ifdef DEBUG public blocked blocked dw 0 ; endif ;-------------------------------------------------------------------- ;int 21 trap ;-------------------------------------------------------------------- ;trap is in effect only during srvx context: ; trapped to (1) force error on mem alloc's (2) clean up if task ; terminates ;-------------------------------------------------------------------- ifdef DEBUG public i21_trap endif i21_trap: push ax ;check for user interrupted our thread mov ax,ss cmp ax,DGROUP pop ax jnz dtr2 cmp ah,4ch ;terminate? jz killtask cmp ah,48h ;alloc? jz dtr1 cmp ah,4ah ;mod alloc? jnz dtr2 dtr1: mov ax,8 ;no mem dos err xor bx,bx stc sti retf 2 dtr2: jmp cs:i21_passon ;-------------------------------------------------------------------- ;killtask ;-------------------------------------------------------------------- ;entered from i21_trap if server task issued dos terminate call ;unhook from traps, release all memory disappear ; ;NOTE: if this is to be used with other tsr's, then they should ;be removed first if they are loaded after this. ;-------------------------------------------------------------------- ifdef DEBUG public killtask, clsall endif killtask: mov ax,DGROUP mov ds,ax assume ds:DGROUP push ds assume ds:nothing ;unlink int traps les bx,cs:upost_passon mov ax,0b804h int 2fh lds dx,cs:i2f_passon DOS 252fh pop ds assume ds:DGROUP ;close all open files mov es,__psp push ds lds si,es:[0].pp_fidtblptr mov cx,es:[0].pp_fidtbllen xor bx,bx clsall: cmp BY [si+bx],0ffh jz cla1 DOS 3eh cla1: inc bx loop clsall pop ds ;free all memory associated with task mov es,__psp mov ax,es:[0].pp_envseg ;env ptr mov es,ax or ax,ax jz kt1 DOS 49h ;free env kt1: lea si,__abrktb+4 ;free all far segs mov cx,MAXSEG-1 kt2: mov ax,[si+2] or ax,ax jz kt3 mov es,ax DOS 49h add si,4 loop kt2 kt3: mov es,__psp ;free the main seg DOS 49h ;flag killed mov cs:srvx_killed,1 ;return to interrupted thread call far ptr _srvx_wait ;won't return assume ds:nothing ;-------------------------------------------------------------------- ; srvx_trap ;-------------------------------------------------------------------- ; ;This is the linkage to the resident file server. ;When the server receives a message from a workstation, we get to ;take a look at it and process it if we want to. ; ;The linkage was set up with int 2f, ax=b803 (get current post address) ;and int 2f, ax=b804 (set new post address). ; ;On entry: ; if ax == 0010h then ; /* smb request from user */ ; ds:di points to the SMB message ; cx has max length for response smb. ; es:bx ptr to NCB ; dx has net bios session number ; if ax == 0106h then ; /* user has 'called' via netbios */ ; es:bx ptr to NCB ; dx has net bios session number ; if ax == 0105h then ; /* user has 'hung-up' via netbios */ ; es:bx ptr to NCB ; dx has net bios session number ; ; ;On exit: if we processed the message, iret with ax = 0 (actually jmps ;to got_request to resume our main code). If we don't process the ;message, then jmp to the next server extension (via address obtained ;on int 2f, ax=b803) ; ;No registers other than ax are changed. If we process SMB, then ;ax is set to 0. ;-------------------------------------------------------------------- ifdef DEBUG public srvx_trap endif srvx_trap: cmp ax,105h ;disconnect code? jnz sxt2 push ax mov ax,SXEVrudis call got_req pop ax jmp short sxt3 sxt2: cmp ax,10h ;is it SMB type? jz sxt4 ;keep checking if so sxt3: jmp cs:upost_passon ;pass to next extension sxt4: cmp [di].sm_cmd,0ffh ;is SMB command code an 'escape' jnz sxt3 ;if not, pass to next cld ; push es ;save regs needed for signature push ds ; compare push cx push di push si mov si,di ;ds:si -> smb add si,sm_res ;-> smb signature field push cs pop es mov di,OTX srvx_name ;name of our server extension mov cx,8/2 repz cmpsw ;will match if user made this SMB pop si ; with us in mind pop di pop cx pop ds pop es jnz sxt3 ;jmp if not for us mov ax,0 push ax ;ax = 0 to indicate msg processed mov ax,SXEVrusmb call got_req ;get back to waiting main program pop ax jnc sxt1 ;if not killed while in prog mov ax,10h jmp sxt3 sxt1: iret ;-------------------------------------------------------------------- ; i2f_trap ;-------------------------------------------------------------------- ; ;Monitors int 2f for our multiplex ID assigned at startup time. ; int 2f, ah=id, al=0 is used for an install check. ; int 2f, ah=id, al!=1 is mechanism for local user (foreground process) ; to issue a request to us. In this case, user ; passes an SMB-like data structure in ds:di to us ; and cx has smb max len ; ;only AX is changed ;-------------------------------------------------------------------- ifdef DEBUG public i2f_trap endif i2f_trap: cmp ah,cs:srvx_mid ;make sure our mux ID jz muxus jmp cs:i2f_passon ;pass to next int 2f handler muxus: or al,al jnz mux1 ;jmp if not install check inc al ;return 'is installed' mux0: iret mux1: cld ;alway fwd dir cmp al,1 jz mux2 mov ax,0 push ax mov ax,SXEVludis jmp short mux3 mux2: mov ax,0 push ax mov ax,SXEVlusmb ;flag that request is from local proc mux3: call got_req ;get to waiting main program pop ax jnc mux4 ;if not killed while in prog mov al,1 ;flag killed to user mux4: iret ;-------------------------------------------------------------------- ; far srvx_wait(); ;-------------------------------------------------------------------- ; ;Main code calls this to wait on next user request. At the same time, ;the reply for the just-completed request is returned to the user (except ;the first time). ; ;The first time called, we will end up doing a DOS 'terminate stay resident'. ;The saved stack info was set up in init to cause a return to the TSR code. ; ;input: none ;output: (SMB far *) srvx_smb is pointer to the SMB associated with request ; We build response in this smb also. ; (unsigned) srvx_smbmax specifies maximum size of smb for response. ; returns 1 if request came from user via server, else 2 if request ; was via int 2f (local user) ;-------------------------------------------------------------------- public _srvx_wait _srvx_wait proc far _srvx_wait endp PUSHM <bp,di,si,ds> mov cs:x_sp,sp ;save our sp mov cs:x_ss,ss mov di,OTX x_ctxt ;save our context call save_context ;remove the int 21 trap lds dx,cs:i21_passon DOS 2521h mov si,OTX u_ctxt ;restore user's context call restore_context cli mov ss,cs:u_ss ;user's sp restored mov sp,cs:u_sp sti POPM <bx,cx,dx,si,di,bp,ds,es> mov al,0 cli xchg al,cs:srvx_lock cmp al,SXEVlusmb jnz sxw1 cmp cs:srvx_waiting,0 jz sxw1 sti mov ah,84h int 2ah sxw1: xor ax,ax ;cf clear to indicate not killed ret ;return to (1) server or (2) local ;user that did an int 2f ;-------------------------------------------------------------------- ; got_req ;-------------------------------------------------------------------- ; ;This can be viewed as a continuation of respond_wait. Gets control when ;there is another (SMB) request to be processed ; ;in: al = 1 if from server, 2 if from local user ; ;It is possible for server and local user to make requests asynchronously. ;However, mutual exclusion lock is done here so that higher level has ;to worry about only 1 request at a time. Undoc'd DOS 3.x int 2a, ah=84 ;function is used to sleep when it is found that other thread is using ;our code. ;-------------------------------------------------------------------- ifdef DEBUG public got_req endif got_req: gr1: cli ;ints off for lock'd test cmp cs:srvx_lock,0 jz gr2 ;jmp if not locked mov cs:srvx_waiting,al sti ifdef DEBUG inc cs:blocked endif push ax mov ah,84h ;sleep till tick or other event int 2ah pop ax jmp gr1 gr2: mov cs:srvx_waiting,0 cmp cs:srvx_killed,0 jz gr3 stc ret gr3: mov cs:cs:srvx_lock,al ;no locked so lock for us sti PUSHM <es,ds,bp,di,si,dx,cx,bx> push ds push ax mov ax,seg DGROUP mov ds,ax assume ds:DGROUP pop _srvx_eventcode ;what caused wakeup pop WO _srvx_smb+2 mov WO _srvx_smb,di ;save smb ptr in global var mov _srvx_smbmax,cx ;save smb max len in global mov WO _srvx_ncb,bx mov WO _srvx_ncb+2,es mov _srvx_ses,dx assume ds:nothing mov u_sp,sp ;save user sp mov u_ss,ss cli mov ss,x_ss ;restore srvx's stack mov sp,x_sp sti mov di,OTX u_ctxt ;save user's context call save_context mov si,OTX x_ctxt ;restore srvx's context call restore_context ;set up a trap on server's int 21 functions DOS 3521h mov WO cs:i21_passon,bx mov WO cs:i21_passon+2,es mov dx,OTX i21_trap mov ax,cs mov ds,ax DOS 2521h POPM <ds,si,di,bp> ;restore C regs retf ;-------------------------------------------------------------------- ;save_context ;-------------------------------------------------------------------- ;utility used to save current context ;in: ; cs:di = save area ;out: ; ax,di,si,ds,es destroyed ; ;-------------------------------------------------------------------- ifdef DEBUG public save_context endif save_context: cld mov cx,cs mov es,cx ;es:di -> save xor cx,cx mov ds,cx mov si,1bh*4 ;get int 1b vect cld movsw movsw mov si,23h*4 ;get ints 23,24 vects movsw movsw movsw movsw lds si,cs:dos_state mov cx,cs:dctx_szsmall shr cx,1 rep movsw jnc sst1 movsb sst1: ret ;-------------------------------------------------------------------- ;restore_context ;-------------------------------------------------------------------- ;utility used to save current context ;in: ; cs:si = save area ;out: ; cx,di,si,es,ds destroyed ; ;-------------------------------------------------------------------- ifdef DEBUG public restore_context endif restore_context: cld mov ax,cs mov ds,ax ;ds:si -> save area xor ax,ax mov es,cx mov di,1bh*4 ;set int 1b vect cli movsw movsw mov di,23h*4 ;get ints 23,24 vects movsw movsw movsw movsw sti les di,cs:dos_state mov cx,cs:dctx_szsmall shr cx,1 rep movsw jnc rst1 movsb rst1: ret ;-------------------------------------------------------------------- ;misc dos traps ;-------------------------------------------------------------------- ;these are set during task (server) context ;i24 (critical err) just causes dos call to fail ;i23 (ctl-brk dos) don't let user trap get control ;i1b (ctl-brk bios) " " " " " " ; ;note: during heavy server activity ctl-brks may get lost. ;-------------------------------------------------------------------- ;misc default traps for task context ifdef DEBUG public i24_trap,i1b_trap,i23_trap endif i24_trap: mov al,3 ;fail the call i1b_trap: i23_trap: iret ;-------------------------------------------------------------------- ; srvx_init ;-------------------------------------------------------------------- ; ;srvx_init(name, mid) ; char far *name; /* name of srvx process, 8 chars long */ ; int mid; /* our ID on mux (int 2fh) chain ; ; ;assumes srvx_preinit() has been called to verify system ready ;called from ctsmsg to divide the system into two processes -- the ;user and the server task. When it returns, the server task is ;running and the user is suspended. When the server suspends, the ;user will resume at a go term/stay resident instruction, which will ;return to the shell, leaving the server in memory (the user has its ;own little stack for this exit process) ; ;for the C small and medium models, this cuts off the heap at its ;first free space. for other models, the thing to do is link ;with /CP:1 as noted in MS C users guide ; ;the dos internal handle table is moved to a bigger area so more ;files can be opened by the server task. ;-------------------------------------------------------------------- ;this routine gets control on first call to srvx_wait(). It ;sets up this code as a resident program. ifdef DEBUG public got_req endif go_tsr: cli DOS 3100h __name = 6 __mid = 10 public _srvx_init _srvx_init proc far push bp mov bp,sp push di push si assume ds:DGROUP ;cut off mem alloc call fxalloc push ds ifdef FID_TABLE_SZ ; set bigger file id table for dos mov es,__psp lds si,es:[0].pp_fidtblptr assume ds:nothing mov cx,es:[0].pp_fidtbllen cmp cx,FID_TABLE_SZ jae iti2 mov di,OTX fid_table mov WO es:[0].pp_fidtblptr,di mov WO es:[0].pp_fidtblptr+2,cs mov es:[0].pp_fidtbllen,FID_TABLE_SZ push cs pop es rep movsb ;copy already open file ids iti2: endif assume ds:nothing ;copy name to static buffer push cs pop es mov di,OTX srvx_name lds si,DWO [bp+__name] cld mov cx,8/2 rep movsw ; copy current context to user context save ; (the first "user" is us, going tsr on first call to srvx_wait()) mov di,OTX u_ctxt call save_context push cs pop ds ; turn off break checking mov dl,0 DOS 3301h ;set up error traps mov dx,OTX i1b_trap DOS 251bh mov dx,OTX i23_trap DOS 2523h mov dx,OTX i24_trap DOS 2524h ;set up a trap on server's int 21 functions DOS 3521h mov WO cs:i21_passon,bx mov WO cs:i21_passon+2,es mov dx,OTX i21_trap mov ax,cs mov ds,ax DOS 2521h ; set mux int trap mov ax,[bp+__mid] mov cs:srvx_mid,al DOS 352fh mov WO cs:i2f_passon,bx mov WO cs:i2f_passon+2,es mov dx,OTX i2f_trap DOS 252fh ; set server extension trap mov ax,0b803h int 2fh mov WO cs:upost_passon,bx mov WO cs:upost_passon+2,es push cs pop es mov bx,OTX srvx_trap mov ax,0b804h int 2fh ; restore dos's div by 0 trap mov ax,seg DGROUP mov ds,ax assume ds:DGROUP lds dx,__aintdiv assume ds:nothing DOS 2500h xor ax,ax pop ds assume ds:nothing itxit: pop si pop di pop bp ret _srvx_init endp ;-------------------------------------------------------------------- ;UCOUNT srvx_preinit(muxid) ;-------------------------------------------------------------------- ;-------------------------------------------------------------------- __midi = 6 public _srvx_preinit _srvx_preinit proc far push bp mov bp,sp push di push si ; check dos version DOS 30h cmp al,3 jz tpi1 mov ax,1 ;return 1 for bad dos ver jmp tpi2 tpi1: mov ax,0b800h ;test for server installed int 2fh or al,al mov ax,2 jz tpi2 ;ret 2 if not installed test bx,40h mov ax,3 jz tpi2 ;ret 3 if not server mov ax,[bp+__midi] mov ah,al mov al,0 int 2fh or al,al mov ax,4 jnz tpi2 ;ret 4 if srvx already installed ;get addr and size of DOS data for context sw push ds DOS 5d06h ;see notes in struc section mov ax,ds pop ds mov WO cs:dos_state,si mov WO cs:dos_state+2,ax mov cs:dctx_szsmall,dx mov cs:dctx_szlarge,cx ;(this not used) xor ax,ax ;ret 0 if all ok tpi2: pop si pop di pop bp ret _srvx_preinit endp ;-------------------------------------------------------------------- ;fxalloc ;-------------------------------------------------------------------- ;if no _fmallocs have been done, this cuts off the main data seg ;just past last used heap space. This works for MSC 3 and 4, and ;probably for 5 too. ; ;the size of the main segment (psp to end of data seg) is saved ;for the TSR parameter ;-------------------------------------------------------------------- ifdef DEBUG public fxalloc endif assume ds:DGROUP fxalloc: cmp __abrktb+6,0 ;_abrktb[1].sg jnz fx6 mov si,__asegds+0 ;_asegds.bottom or si,si jnz fx1 mov di,__abrktb ;__abrktb[0].sz jmp fx5a ;make di end of dseg fx1: mov __asegds+2,si ;_asegds.roveroff xor di,di fx2: mov ax,[si] cmp ax,0fffeh jz fx4 test ax,1 jnz fx3 mov di,si ;last alloc'd block found fx3: and ax,not 1 add si,ax add si,2 jmp fx2 fx4: or di,di jnz fx5 mov di,__abrktb mov WO [di],1 ;dummy free block fx5: mov ax,[di] and ax,not 1 add di,ax add di,2 mov WO [di],0fffeh add di,2 mov __asegds+6,di ;_asegds.top mov __abrktb,di ;_abrktb[0].sz fx5a: mov __asizds,di mov ax,di add ax,15 rcr ax,1 mov cl,3 shr ax,cl mov es,__psp mov bx,ds add ax,bx mov es:[0].pp_mtop,ax DOS 4ah fx6: mov bx,__psp mov es,bx mov ax,es:[0].pp_mtop ;get main seg size sub ax,bx mov cs:task_memsize,ax ret assume ds:nothing ;-------------------------------------------------------------------- ;farcpybuf(far *dest, far * src, count) ;-------------------------------------------------------------------- ;so that c code can be any model ;-------------------------------------------------------------------- public _farcpybuf _farcpybuf proc far push bp mov bp,sp PUSHM <si,di,ds> les di,DWO [bp+6] lds si,DWO [bp+10] mov cx,[bp+14] shr cx,1 jz fcp1 rep movsw fcp1: jnc fcp2 movsb fcp2: POPM <ds,di,si> pop bp ret _farcpybuf endp END_MOD end