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Assembly Source File | 1991-11-15 | 25.5 KB | 645 lines

name dump page 55,132 title DUMP --- Display File Contents .286c ; ; DUMP.ASM --- a OS/2 utility to display the contents of a ; file on the standard output in hex and ASCII format. ; ; Copyright (C) 1987 Ray Duncan ; ; Usage: C>DUMP path\filename.ext [ >device ] ; ; This program has been intentionally complicated ; to demonstrate the use of multiple threads and semaphores ; in a MASM application. For a roadmap to what is going ; on in this program, see its counterpart DUMP.C. ; cr equ 0dh ; ASCII carriage return lf equ 0ah ; ASCII line feed blank equ 20h ; ASCII space code tab equ 09h ; ASCII tab code recsize equ 16 ; size of input file records stksize equ 2048 ; size of stack for threads stdout equ 1 ; handle of standard output device stderr equ 2 ; handle of standard error device extrn DOSOPEN:far ; references to OS/2 services extrn DOSREAD:far extrn DOSWRITE:far extrn DOSCLOSE:far extrn DOSEXIT:far extrn DOSSEMCLEAR:far extrn DOSSEMSET:far extrn DOSSEMWAIT:far extrn DOSALLOCSEG:far extrn DOSCREATETHREAD:far extrn DOSSUSPENDTHREAD:far extrn DOSENTERCRITSEC:far extrn DOSEXITCRITSEC:far extrn DOSGETENV:far DGROUP group _DATA _DATA segment word public 'DATA' ExitSem dd 0 ; storage for RAM semaphores Buf1FullSem dd 0 Buf1EmptySem dd 0 Buf2FullSem dd 0 Buf2EmptySem dd 0 DisplayThrID dw 0 ; Display thread ID DiskThrID dw 0 ; Disk I/O thread ID Buf1 db recsize dup (0) ; disk I/O buffer #1 Buf1Len dw 0 ; length of buffer #1 data Buf2 db recsize dup (0) ; disk I/O buffer #2 Buf2Len dw 0 ; length of buffer #2 data fname db 64 dup (0) ; ASCIIZ name of input file fhandle dw 0 ; handle for input file filptr dw 0 ; relative address in file status dw 0 ; receives status of DOSOPEN selector dw 0 ; receives segment selector ; from DOSALLOCSEG ; formatting area for output output db 'nnnn',blank,blank outputa db 16 dup ('nn',blank) db blank outputb db 16 dup (blank),cr,lf output_len equ $-output heading db cr,lf ; heading for each 128 bytes db 7 dup (blank) db '0 1 2 3 4 5 6 7 ' db '8 9 A B C D E F',cr,lf heading_len equ $-heading msg1 db cr,lf db 'dump: file not found' db cr,lf msg1_len equ $-msg1 msg2 db cr,lf db 'dump: missing file name' db cr,lf msg2_len equ $-msg2 msg3 db cr,lf db 'dump: memory allocation error' db cr,lf msg3_len equ $-msg3 msg4 db cr,lf db 'dump: create thread failed' db cr,lf msg4_len equ $-msg4 _DATA ends _TEXT segment word public 'CODE' assume cs:_TEXT,ds:DGROUP dump proc far ; entry point from OS/2 call argc ; is filename present? cmp ax,2 je dump1 ; yes, proceed mov dx,offset msg2 ; missing or illegal filespec, mov cx,msg2_len jmp dump9 ; print error message and exit. dump1: ; copy filename to local buffer mov ax,1 ; get ES:BX = filename call argv mov cx,ax ; set CX = length mov di,offset fname ; DS:DI = local buffer dump15: mov al,es:[bx] ; copy it byte by byte mov [di],al inc bx inc di loop dump15 push ds ; set ES = DS pop es dump2: ; now try to open file... push ds ; ASCIIZ file name push offset DGROUP:fname push ds ; receives handle push offset DGROUP:fhandle push ds ; receives handle push offset DGROUP:status push 0 ; file size (ignored) push 0 push 0 ; file attribute = normal push 1 ; OpenFlag = fail if doesn't exist push 40h ; OpenMode = deny none,read only push 0 ; DWORD reserved push 0 call DOSOPEN ; transfer to OS/2 or ax,ax ; test status jz dump3 ; jump if open succeeded mov dx,offset msg1 ; open of input file failed, mov cx,msg1_len jmp dump9 ; print error msg and exit. dump3: ; initialize semaphores push ds push offset DGROUP:ExitSem call DOSSEMSET push ds push offset DGROUP:Buf1FullSem call DOSSEMSET push ds push offset DGROUP:Buf2FullSem call DOSSEMSET ; allocate Disk Thread stack push stksize ; size of stack push ds ; receives selector for push offset DGROUP:selector ; allocated block push 0 ; 0 = segment not shareable call DOSALLOCSEG ; transfer to OS/2 or ax,ax ; test status jz dump5 ; jump if allocation succeeded dump4: mov dx,offset DGROUP:msg3 ; display message mov cx,msg3_len ; 'memory allocation error' jmp dump9 ; and exit dump5: ; create Disk Thread push cs ; thread's entry point push offset _TEXT:DiskThread push ds ; receives thread ID push offset DGROUP:DiskThrID push selector ; thread's stack base push stksize call DOSCREATETHREAD ; transfer to OS/2 or ax,ax ; test status jz dump7 ; jump if create succeeded dump6: mov dx,offset DGROUP:msg4 ; create of thread failed, mov cx,msg4_len ; display error message jmp dump9 ; and exit dump7: ; allocate Display Thread stack push stksize ; size of stack push ds ; receives selector for push offset DGROUP:selector ; allocated block push 0 ; 0 = segment not shareable call DOSALLOCSEG ; transfer to OS/2 or ax,ax ; test status jnz dump4 ; jump if allocation failed ; create Display Thread push cs ; thread's entry point push offset _TEXT:DisplayThread push ds ; receives thread ID push offset DGROUP:DisplayThrID push selector ; thread's stack base push stksize call DOSCREATETHREAD ; transfer to OS/2 or ax,ax ; test status jnz dump6 ; jump if create failed push ds ; now wait on exit semaphore push offset DGROUP:ExitSem ; (it will be triggered push -1 ; by routine DumpRec when push -1 ; end of file is reached) call DOSSEMWAIT ; transfer to OS/2 push DiskThrID ; suspend Disk Thread call DOSSUSPENDTHREAD ; transfer to OS/2 push DisplayThrID ; suspend Display Thread call DOSSUSPENDTHREAD ; transfer to OS/2 push fhandle ; close the input file call DOSCLOSE ; transfer to OS/2 push 1 ; terminate all threads push 0 ; return code 0 for success call DOSEXIT ; final exit to OS/2 dump9: ; print error message... push stderr ; standard error device handle push ds ; address of message push dx push cx ; length of message push ds ; receives bytes written push offset DGROUP:status call DOSWRITE ; transfer to OS/2 push 1 ; terminate all threads push 1 ; return code <>0 for error call DOSEXIT ; final exit to OS/2 dump endp DiskThread proc far ; this thread performs ; the file I/O, alternating ; between the two buffers ; fill buffer #1 push fhandle ; handle for input file push ds ; address of buffer #1 push offset DGROUP:Buf1 push recsize ; record length requested push ds ; receives bytes read push offset DGROUP: Buf1Len call DOSREAD ; signal buffer 1 has data mov si,offset DGROUP:Buf1EmptySem mov di,offset DGROUP:Buf1FullSem call SemFlip push ds ; wait until buffer 2 empty push offset DGROUP:Buf2EmptySem push -1 push -1 call DOSSEMWAIT ; fill buffer #2 push fhandle ; handle for input file push ds ; address of buffer #1 push offset DGROUP:Buf2 push recsize ; record length requested push ds ; receives bytes read push offset DGROUP:Buf2Len call DOSREAD ; signal buffer 2 has data mov si,offset DGROUP:Buf2EmptySem mov di,offset DGROUP:Buf2FullSem call SemFlip push ds ; wait until buffer 1 empty push offset DGROUP:Buf1EmptySem push -1 push -1 call DOSSEMWAIT jmp DiskThread ; do it again... DiskThread endp DisplayThread proc far ; formats and displays disk ; data, alternating between ; the two disk buffers push ds ; wait until buffer #1 full push offset DGROUP:Buf1FullSem push -1 push -1 call DOSSEMWAIT mov si,offset DGROUP:Buf1 ; display buffer 1 mov cx,Buf1Len call DumpRec ; signal buffer #1 is emptied mov si,offset DGROUP:Buf1FullSem mov di,offset DGROUP:Buf1EmptySem call SemFlip push ds ; wait until buffer #2 full push offset DGROUP:Buf2FullSem push -1 push -1 call DOSSEMWAIT mov si,offset DGROUP:Buf2 ; display buffer 2 mov cx,Buf2Len call DumpRec ; signal buffer #2 is emptied mov si,offset DGROUP:Buf2FullSem mov di,offset DGROUP:Buf2EmptySem call SemFlip jmp DisplayThread ; do it again... DisplayThread endp SemFlip proc near ; Flip status of two ; semaphores atomically call DOSENTERCRITSEC ; protect this code sequence push ds ; set semaphore #1 push si call DOSSEMSET push ds ; clear semaphore #2 push di call DOSSEMCLEAR call DOSEXITCRITSEC ; let other threads run again ret SemFlip endp DumpRec proc near ; formats and displays ; contents of buffer ; DS:SI = buffer, CX = length or cx,cx ; anything to format? jnz DumpRec1 ; yes, continue push ds ; no, clear exit semaphore push offset DGROUP:ExitSem ; (releasing wait condition call DOSSEMCLEAR ; for main thread) push 0 ; and terminate this thread push 0 call DOSEXIT DumpRec1: ; time for a heading? test filptr,07fh ; if 128 byte boundary jnz DumpRec2 ; no,jump push stdout ; standard output device handle push ds ; address of heading text push offset DGROUP:heading push heading_len ; length of heading push ds ; receives bytes written push offset DGROUP:status call DOSWRITE DumpRec2: ; format record data... push cx ; save record length mov di,offset output ; first clear output area mov cx,output_len-2 mov al,blank rep stosb mov di,offset output ; convert current file offset mov ax,filptr ; to ASCII for output call w2hex pop cx ; get back record length mov bx,0 ; initialize record pointer DumpRec3: ; fetch next byte from buffer mov al,[si+bx] ; store ASCII version of character mov di,offset outputb ; calculate output string address mov byte ptr [di+bx],'.' ; if not alphanumeric cmp al,blank ; just print a dot. jb DumpRec4 ; jump, not alphanumeric. cmp al,7eh ja DumpRec4 ; jump, not alphanumeric. mov [di+bx],al ; else store ASCII character. DumpRec4: ; now convert binary byte ; to hex ASCII equivalent mov di,offset outputa ; calc. position in output string add di,bx ; base addr + (offset*3) add di,bx add di,bx ; convert data in AL to hex call b2hex ; ASCII and store into output inc bx ; bump data pointer and loop loop DumpRec3 ; until entire record converted ; now display formatted data push stdout ; standard output device handle push ds ; address of text push offset DGROUP:output push output_len ; length of text push ds push offset DGROUP:status ; receives bytes written call DOSWRITE add word ptr filptr,recsize ; update file pointer ret ; return to caller DumpRec endp argc proc near ; count command line arguments ; returns count in AX enter 4,0 ; make room for local variables ; and give them names... envseg equ [bp-2] ; environment segment cmdoffs equ [bp-4] ; command line offset push es ; save original ES,BX, and CX push bx push cx push ss ; get selector for environment lea ax,envseg ; and offset of command line push ax push ss lea ax,cmdoffs push ax call DOSGETENV ; transfer to OS/2 or ax,ax ; check operation status mov ax,1 ; force argc >= 1 jnz argc3 ; inexplicable failure mov es,envseg ; set ES:BX = command line mov bx,cmdoffs argc0: inc bx ; ignore useless first field cmp byte ptr es:[bx],0 jne argc0 argc1: mov cx,-1 ; set flag = outside argument argc2: inc bx ; point to next character cmp byte ptr es:[bx],0 je argc3 ; exit if null byte cmp byte ptr es:[bx],blank je argc1 ; outside argument if ASCII blank cmp byte ptr es:[bx],tab je argc1 ; outside argument if ASCII tab ; otherwise not blank or tab, jcxz argc2 ; jump if already inside argument inc ax ; else found argument, count it not cx ; set flag = inside argument jmp argc2 ; and look at next character argc3: pop cx ; restore original BX, CX, ES pop bx pop es leave ; discard local variables ret ; return AX = argument count argc endp argv proc near ; get address and length ; of command line arguments ; call with AX = arg. no. ; return ES:BX = address of ; argument string, CX = length enter 4,0 ; make room for local variables push cx ; save original CX and DI push di push ax ; save argument number push ss ; get selector for environment lea ax,envseg ; and offset of command line push ax push ss lea ax,cmdoffs push ax call DOSGETENV ; transfer to OS/2 or ax,ax ; test operation status pop ax ; restore argument number jnz argv7 ; jump if DOSGETENV failed mov es,envseg ; set ES:BX = command line mov bx,cmdoffs or ax,ax ; is requested argument=0? jz argv8 ; yes, jump to get program name argv0: inc bx ; scan off first field cmp byte ptr es:[bx],0 jne argv0 xor ah,ah ; initialize argument counter argv1: mov cx,-1 ; set flag = outside argument argv2: inc bx ; point to next character cmp byte ptr es:[bx],0 je argv7 ; exit if null byte cmp byte ptr es:[bx],blank je argv1 ; outside argument if ASCII blank cmp byte ptr es:[bx],tab je argv1 ; outside argument if ASCII tab ; if not blank or tab... jcxz argv2 ; jump if already inside argument inc ah ; else count arguments found cmp ah,al ; is this the one we need? je argv4 ; yes, go find its length not cx ; no, set flag = inside argument jmp argv2 ; and look at next character argv4: ; found desired argument, now ; determine its length... mov ax,bx ; save param. starting address argv5: inc bx ; point to next character cmp byte ptr es:[bx],0 je argv6 ; found end if null byte cmp byte ptr es:[bx],blank je argv6 ; found end if ASCII blank cmp byte ptr es:[bx],tab jne argv5 ; found end if ASCII tab argv6: xchg bx,ax ; set ES:BX = argument address sub ax,bx ; and AX = argument length jmp argvx ; return to caller argv7: xor ax,ax ; set AX = 0, argument not found jmp argvx ; return to caller argv8: ; special handling for argv=0 xor di,di ; find the program name by xor al,al ; first skipping over all the mov cx,-1 ; environment variables... cld argv9: repne scasb ; scan for double null (can't use scasb ; (SCASW since might be odd addr.) jne argv9 ; loop if it was a single null mov bx,di ; save program name address mov cx,-1 ; now find its length... repne scasb ; scan for another null byte not cx ; convert CX to length dec cx mov ax,cx ; return length in AX argvx: ; common exit point pop di ; restore original CX and DI pop cx leave ; discard stack frame ret ; return to caller argv endp w2hex proc near ; convert word to hex ASCII ; call with AX=binary value ; DI=addr to store string ; returns AX, DI destroyed push ax mov al,ah call b2hex ; convert upper byte pop ax call b2hex ; convert lower byte ret ; back to caller w2hex endp b2hex proc near ; convert byte to hex ASCII ; call with AL=binary value ; DI=addr to store string ; returns AX, DI destroyed push cx ; save CX for later sub ah,ah ; clear upper byte mov cl,16 div cl ; divide binary data by 16 call ascii ; the quotient becomes the first stosb ; ASCII character mov al,ah call ascii ; the remainder becomes the stosb ; second ASCII character pop cx ; restore contents of CX ret b2hex endp ascii proc near ; convert value 0-0FH in AL ; into a "hex ASCII" character add al,'0' cmp al,'9' jle ascii2 ; jump if in range 0-9, add al,'A'-'9'-1 ; offset it to range A-F, ascii2: ret ; return ASCII char. in AL. ascii endp _TEXT ends end dump