Simtel MSDOS 1992 June

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/ Simtel MSDOS 1992 June / SIMTEL_0692.cdr / msdos / sysutl / pcmap.arc / PCMAP.ASM next >

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Assembly Source File | 1987-04-30 | 9.2 KB | 301 lines

;---------------------------------------------------------------------- ; PCMAP - Search through memory and print out the program names (for ; DOS 3.x) and the number of bytes assigned to each in memory. ;---------------------------------------------------------------------- CSEG SEGMENT PARA PUBLIC 'CODE' ;Start CODE segment ASSUME CS:CSEG,DS:CSEG,ES:CSEG,SS:CSEG ;Set by DOS Loader ORG 100H ;COM file format CR EQU 0DH ;Common equates LF EQU 0AH TAB EQU 09H ENTPT: JMP PCMAP ;Jump over data ;====================================================================== COPYRIGHT DB "PCMAP 1.0 (c) 1987, Ziff-Davis Publishing Corp." AUTHOR DB CR,LF,LF,'$',1AH,"Robert L. Hummel" HEADING_MSG DB "Segment Paragraphs Program" CR_LF_MSG DB CR,LF,'$' COM_MSG DB "COMMAND.COM" UNK_MSG DB "(Unknown)" FREE_MSG DB "(Free)" SPACE_MSG DB 7 DUP(' '),'$' N_BLK DB 0 ;Count table entries VER3 DB 0 ;=1 if Version 3.x ;====================================================================== PCMAP PROC NEAR MOV DX,OFFSET COPYRIGHT MOV AH,9 ;Display string INT 21H ; Thru DOS MOV AH,30H ;Check DOS version INT 21H ; Thru DOS CMP AL,3 ;If not 3.x JB NOT_3 ; don't turn on flag INC VER3 ; else, indicate NOT_3: ;---------------------------------------------------------------------- ; Find the first MCB by scanning through memory. ; On exit, ES points to the MCB. ; AX=Block Address, BX=ES, CX=Owner, DX=Top of memory. ;---------------------------------------------------------------------- XOR BX,BX ;Zero BX SEARCH_MEM: MOV ES,BX ;Point segment to 0 ASSUME ES:NOTHING ;Tell the assembler CMP BYTE PTR ES:[0],'M' ;Is this a MCB? JE CHECK_MCB ; might be CRAWL: INC BX ;Point to next segment JMP SEARCH_MEM ; continue search CHECK_MCB: MOV AX,BX ;The MCB segment should INC AX ; belong to the next segment MOV CX,WORD PTR ES:[1] ;If owner of this block CMP AX,CX ; is the same as the block JNE CRAWL ; is first legitamate block FOUND_FIRST: MOV DX,WORD PTR DS:[2] ;Top of memory ;---------------------------------------------------------------------- ; If the owner=0, then this block is unallocated (free). ; AX=Mem Address, BX=ES, CX=Owner, DX=Top of memory. ; Look up OWNER in table. ;---------------------------------------------------------------------- WORM_1: CLD ;String moves forward MOV DI,OFFSET TABLE ;Where to look MOV CX,WORD PTR ES:[1] ;Get owner of this block MOV AL,N_BLK ; number to look at SEARCH_TABLE: OR AL,AL ;If no entries are left JZ CREATE_ENTRY ; create a new one DEC AL ;Adjust valid entries OR CX,CX ;If unallocated JZ SKIP_ENTRY ; just skip to end MOV SI,WORD PTR [DI] ;Get PID of owner CMP CX,SI ;If owner matches JE ADD_LEN ; add more length SKIP_ENTRY: ADD DI,17 ;Point to next entry JMP SEARCH_TABLE ;---------------------------------------------------------------------- ; Assume di points to 1st empty spot. ;---------------------------------------------------------------------- CREATE_ENTRY: INC N_BLK ;Adding new entry MOV AX,CX OR CX,CX ;If block is free JNZ NOT_FREE MOV AX,BX ;Put mem address as owner INC AX NOT_FREE: MOV WORD PTR [DI],AX ;Put owner in table MOV WORD PTR [DI][2],0 ;Zero initial length ADD_LEN: MOV SI,WORD PTR ES:[3] ;Block Length INC BX ;Use len to point bx... MOV AX,BX ; (point AX to mem) ADD BX,SI ;...to next MCB ADD WORD PTR [DI][2],SI ;Increase para count MOV SI,OFFSET FREE_MSG ;Memory is free OR CX,CX ; if owner = 0 JNZ HAVE_OWNER MOV CX,6 ;Length of string JMP COPY_NAME ;Copy to TABLE HAVE_OWNER: ;---------------------------------------------------------------------- ; Is this block a primary (program) block? ;---------------------------------------------------------------------- CMP AX,CX ;Is mem = owner JNE FIND_NEXT ;No ;---------------------------------------------------------------------- ; This is a program block. Word at offset 2Ch into the block contains ; environment segment address. (offset from current ES by 1 paragraph) ;---------------------------------------------------------------------- MOV SI,WORD PTR ES:[2Ch+10h] ;Get env segment CMP N_BLK,1 ;If not first block JNE CHECK_ENV ; look for environment MOV SI,OFFSET COM_MSG ;Put name in table MOV CX,11 ;String length COPY_NAME: ADD DI,4 ;String destination PUSH CS ;Point ES to POP ES ; this segment REP MOVSB ;Move the bytes MOV AL,'$' ;DOS string terminator STOSB ;Store it PUSH CS ;Restore DS POP DS JMP SHORT FIND_NEXT ;---------------------------------------------------------------------- ; Is the environment still allocated to the owner? ;---------------------------------------------------------------------- CHECK_ENV: CMP VER3,0 ;If not 3.x JE NO_ENV ; skip this section DEC SI ;Point to env MCB PUSH SI ;Put seg in DS POP DS CMP CX,WORD PTR DS:[1] ;Compare owners JNZ NO_ENV ;Not our property ;---------------------------------------------------------------------- ; Point DS:SI to the environment and scan for the double zero entry. ;---------------------------------------------------------------------- INC SI ;Point SI to environment PUSH SI ; and put in DS POP DS XOR SI,SI ;DS:SI = ENV:0 INC SI SCAN_ENV: DEC SI ;Backup one byte LODSW ;Look at word OR AX,AX ;If not double 0 byte JNZ SCAN_ENV ;Continue to look ;---------------------------------------------------------------------- ; Find the end of the program pathname. ;---------------------------------------------------------------------- LODSW ;Skip a word (# strings) MOV BP,SI ;Point to 1st char DEC BP SCAN_PATH: LODSB ;Read char at SI OR AL,AL ;If 0, end of string JNZ SCAN_PATH ; else continue reading ;---------------------------------------------------------------------- ; SI points past the terminating 0. Scan backwards for the \. ;---------------------------------------------------------------------- DEC SI ;Point SI to 0 MOV CX,SI ;Point CX past last char SCAN_NAME: DEC SI ;Point to char CMP SI,BP ;Is it 1st char? JE STRING_START CMP BYTE PTR [SI],'\' ;It is backslash? JNE SCAN_NAME ; no, continue STRING_START: INC SI ;Point to start of string SUB CX,SI ;Length of string JMP COPY_NAME ;Transfer NO_ENV: PUSH CS ;Restore DS POP DS MOV CX,9 ;Number of chars MOV SI,OFFSET UNK_MSG ;Unknown JMP COPY_NAME ;Transfer ;---------------------------------------------------------------------- ; Point ES to next MCB and continue search. Stop at top of memory. ;---------------------------------------------------------------------- FIND_NEXT: MOV ES,BX ;Set ES to next paragraph CMP BX,DX ;At top of memory? JE NO_MORE ; then done JMP WORM_1 ;else continue NO_MORE: ;---------------------------------------------------------------------- ; Display the resulting table on the screen. ;---------------------------------------------------------------------- MOV DX,OFFSET HEADING_MSG ;Display the heading MOV AH,9 ;Display string INT 21H ; Thru DOS MOV SI,OFFSET TABLE ;Table location MOV CL,N_BLK ;Number of entries XOR CH,CH ; as a word PRINT_TABLE: CALL PRINT_WORD ;Print owner CALL PRINT_WORD ;and size MOV DX,SI ;Name of owner MOV AH,9 ;Display string INT 21H ; Thru DOS ADD SI,13 ;Point to next entry MOV DX,OFFSET CR_LF_MSG ;Newline MOV AH,9 ;Display string INT 21H ; Thru DOS LOOP PRINT_TABLE MOV AH,4CH ;Terminate program INT 21H ;Thru DOS PCMAP ENDP ;====================================================================== PRINT_WORD PROC NEAR LODSW ;Get owner CALL HEX4 ;Write 4 digits MOV DX,OFFSET SPACE_MSG ;space over MOV AH,9 ;Display string INT 21H ; Thru DOS RET PRINT_WORD ENDP ;====================================================================== ; HEX4 - Write AX as 4 hex digits to console ; HEX2 - Write AL as 2 hex digits to console ;----------------------------------------------------------------------------- HEX4 PROC NEAR PUSH AX ;Save register MOV AL,AH ;Show high digits first CALL HEX2 ;Display AL POP AX ;Restore low digits in AL HEX2 PROC NEAR ;Display AL PUSH AX ;Save register PUSH CX ;Save CX during shift MOV CL,4 SHR AL,CL ;Get high 4 bits POP CX ;Restore CX CALL H2C ;Display upper AL digit POP AX ;Restore lower AND AL,0FH ;Mask and display H2C: ADD AL,90H ;Convert AL to ASCII DAA ADC AL,40H DAA PUSH DX ;Save register during call MOV DL,AL ;Character in DL MOV AH,2 ;Display Output Fn INT 21H ; Thru DOS POP DX ;Restore register RET HEX2 ENDP HEX4 ENDP ;====================================================================== ; Format is TABLE DB 20 DUP (0,0, 0,0," ") ;---------------------------------------------------------------------- TABLE LABEL BYTE ;---------------------------------------------------------------------- CSEG ENDS END ENTPT