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Assembly Source File | 1986-05-11 | 11.4 KB | 386 lines

COMMENT ~ FILES.ASM -- File manipulation Procedures From `BLUEBOOK of ASSEMBLY ROUTINES for the IBM PC & XT' by Christopher L. Morgan Copyright (C) 1984 by The Waite Group, Inc. Contents: --------- CBUF_CLR -- Clear the circular buffer CBUF_IN -- Input to circular buffer CBUF_INIT -- Initialize a circular buffer CBUF_OUT -- Output to a circular buffer CBUF_PUT -- Put a byte into a circular buffer CLOS_FIL -- Close a file EMSG_OUT -- Exception message output FILT_CR* -- Filter for carriage return/linefeed MAKE_FIL -- Create a file READ_FIL -- Read bytes from a file SAVE -- Save a file from communications line to disk WRIT_FIL -- Write bytes to a file >>>>> See FILES.DOC for complete descriptions of these routines. <<<<< ------------------------------------------------------------------------------ It is better to put this data in the source code calling these routines, and then comment out this section. ~ DATAS SEGMENT PUBLIC CR EQU 0DH ;ASCII code for carriage return LF EQU 0AH ;ASCII code for linefeed CTRL_Z EQU 1AH ;ASCII code for ^Z BLK_SIZ = 0 ;K=block size CBUF_SIZ DW 256 ;K=CBUF max capacity CBUF DB 1 ;K=base address of CBUF LBUF DB 256 DUP('LBUF') NAME_BUF DB 64 DUP('NAME') ; ;Following table used by EMSG_OUT EMSG DW EMSG1 DW EMSG2 DW EMSG3 DW EMSG4 DW EMSG5 DW EMSG6 DW EMSG7 DW EMSG8 DW EMSG9 DW EMSG10 DW EMSG11 DW EMSG12 DW EMSG13 DW EMSG14 DW EMSG15 DW EMSG16 DW EMSG17 DW EMSG18 EMSG1 DB CR,LF,'Invalid function number',CR,LF,0 EMSG2 DB CR,LF,'File not found',CR,LF,0 EMSG3 DB CR,LF,'Path not found',CR,LF,0 EMSG4 DB CR,LF,'Too many open files',CR,LF,0 EMSG5 DB CR,LF,'Access denied',CR,LF,0 EMSG6 DB CR,LF,'Invalid handle',CR,LF,0 EMSG7 DB CR,LF,'Memory control blocks destroyed',CR,LF,0 EMSG8 DB CR,LF,'Insufficient memory',CR,LF,0 EMSG9 DB CR,LF,'Invalid memory block address',CR,LF,0 EMSG10 DB CR,LF,'Invalid environment',CR,LF,0 EMSG11 DB CR,LF,'Invalid format',CR,LF,0 EMSG12 DB CR,LF,'Invalid access code',CR,LF,0 EMSG13 DB CR,LF,'Invalid data',CR,LF,0 EMSG14 DB CR,LF,'Message not in use',CR,LF,0 EMSG15 DB CR,LF,'Invalid drive was specified',CR,LF,0 EMSG16 DB CR,LF,'Attempted to remove the current directory',CR,LF,0 EMSG17 DB CR,LF,'Not same device',CR,LF,0 EMSG18 DB CR,LF,'No more files',CR,LF,0 DATAS ENDS ;------------------------------------------------------------------------------ ;It is better to include this data in the source code calling these routines, ; and then comment out this section. STACKS SEGMENT STACK DB 20 DUP(' STACKS ') STACKS ENDS ;------------------------------------------------------------------------------ CODES SEGMENT ;The following variables/constants must be defined in the source code calling ; these routines. See FILES.DOC. EXTRN COM_INCK:FAR,COM_INIT:FAR,COM_ON:FAR,COM_OFF:FAR,MSG_OUT:FAR EXTRN DTA:DWORD,LAST:BYTE,GAUGE:WORD,NEARFULL:WORD,NEAREMPTY:BYTE PUBLIC EMSG_OUT,GET_SPEC,MAKE_FIL,CLOS_FIL,WRIT_FIL,READ_FIL PUBLIC CBUF_INIT,CBUF_PUT,CBUF_IN,CBUF_CLR,CBUF_OUT,SAVE ASSUME CS:CODES,DS:DATAS ;----------------------------I/O ROUTINES-------------------------------------- ;Routine to send out exception messages EMSG_OUT PROC FAR PUSH SI ;Save registers PUSH AX ADD AX,AX ;Double to index through table MOV SI,AX ;SI points into table MOV SI,EMSG[SI] ;Look up address of message CALL MSG_OUT ;Send the message POP AX ;Restore registers POP SI RET EMSG_OUT ENDP ;------------------------------------------------------------------------------ ;Routine to get a file specifier ; GET_SPEC PROC FAR PUSH DS ;Save registers PUSH ES PUSH SI PUSH DI PUSH CX ; ;Set up pointer to DTA to get parameters LDS SI,DTA ;Point to DTA for parameters MOV CL,[SI] ;Get length of string MOV CH,0 ;Make 16-bit INC SI ;Skip the length byte MOV AL,' ' ;Scan past the spaces GET_SPEC1: CMP [SI],AL ;Check for space JNE GET_SPEC2 ;Exit loop if nonspace INC SI ;Else point to next byte LOOP GET_SPEC1 ;Loop back for more JCXZ GET_SPEC3 ;No file specifier? ; ;Move the rest into place GET_SPEC2: MOV DI,DX ;Index points to destination CLD ;Forward direction REP MOVSB ;Make the transfer CLC ;No error, so no carry JMP GET_SPEC_XIT ; and return GET_SPEC3: MOV AX,20 ;No file specified STC ;Set carry for error JMP GET_SPEC_XIT ; and exit GET_SPEC_XIT: POP CX ;Restore registers POP DI POP SI POP ES POP DS RET GET_SPEC ENDP ;------------------------------------------------------------------------------ ;Routine to create a file ; MAKE_FIL PROC FAR PUSH CX ;Save register MOV CX,0 ;Attribute 0 INT 21H ;DOS call POP CX ;Restore register RET MAKE_FIL ENDP ;------------------------------------------------------------------------------ ;Routine to close a file ; CLOS_FIL PROC FAR MOV AH,3EH ;Close a file INT 21H ;DOS call RET CLOS_FIL ENDP ;------------------------------------------------------------------------------ ;Routine to write bytes to a file ; WRIT_FIL PROC FAR MOV AH,40H ;Write to a file INT 21H ;DOS call CMP AX,CX ;Was it all written? JE WRIT_FIL_XIT ;Skip if yes MOV AX,21 ;Not all bytes were transferred STC ;Set carry for error WRIT_FIL_XIT: RET WRIT_FIL ENDP ;------------------------------------------------------------------------------ ;Routine to read bytes from a file ; READ_FIL PROC FAR MOV AH,3FH ;Read from a file INT 21H ;DOS call CMP AX,CX ;Everything back? JE READFIL_XIT ;Skip if yes MOV AX,22 ;Not all read STC ;Set carry for error READFIL_XIT: RET READ_FIL ENDP ;------------------------------------------------------------------------------ ;Routine to handle input for a circular buffer ; CBUF_INIT PROC FAR MOV SI,0 ;Initialize SI MOV DI,0 ;Initialize DI MOV GAUGE,0 ; and # of bytes in buffer MOV LAST,0 ; and last byte buffer RET CBUF_INIT ENDP ;------------------------------------------------------------------------------ ;Routine to one byte into a circular buffer ; CBUF_PUT PROC FAR PUSH DX ;Save register MOV DX,GAUGE ;Put V Guage in DX MOV CBUF[DI],AL ;Put the byte into the buffer INC DI ;Adjust pointer to next char CMP DI,CBUF_SIZ ;Wrap it around? JNE CBUF_PUT1 ;Skip if no wrap MOV DI,0 ;Wraps back to zero CBUF_PUT1: INC DX ;Count the character CMP DX,NEARFULL ;Too many characters? JNE CBUF_PUT_XIT ;Skip if not CALL COM_OFF ;Request to stop flow CBUF_PUT_XIT: POP DX ;Restore register RET CBUF_PUT ENDP ;------------------------------------------------------------------------------ ;Routine to handle input to a circular buffer ; CBUF_IN PROC FAR CALL COM_INCK ;Check for a character JZ CBUF_IN_XIT ;Good exit if none AND AL,7FH ;Strip off parity bit CMP AL,10 ;Check for <LF> (ASCII 10) JNE CBUF_IN1 ;Skip if not <LF> CMP LAST,13 ;Check for <CR> (ASCI 13) JE CBUF_IN2 ;Skip if CR/LF CBUF_IN1: CALL CBUF_PUT ;Put byte into buffer MOV LAST,AL ;Update last byte CBUF_IN2: CMP AL,13 ;Check for <CR> JNE CBUF_IN3 ;Skip if not ; ;Insert LF if character was <CR> PUSH AX ;Save the current character MOV AL,10 ;<LF> CALL CBUF_PUT ; goes into buffer POP AX ;Restore current character ; ;Check for end of file CBUF_IN3: CMP AL,CTRL_Z ;Check for ^-Z (1AH) JE CBUF_IN5 ;EOF is an exception ; ;Check for overflow PUSH DX ;Save register MOV DX,GAUGE CMP DX,NEARFULL ;Overflow of characters? JL CBUF_IN4 ;Skip if not CALL COM_OFF ;Stop flow request JMP CBUF_IN_XIT ;Good exit CBUF_IN4: ;No overflow CALL COM_ON ;Make sure flow is on JMP CBUF_IN_XIT ;Good exit CBUF_IN5: ;EOF exception handling MOV AX,19 ;EOF exception code STC ;Set carry for exception JMP CBUF_IN_RET ;Return with exception CBUF_IN_XIT: POP DX CLC ;Clear carry -- no exception CBUF_IN_RET: RET CBUF_IN ENDP ;------------------------------------------------------------------------------ ;Routine to flush a circular buffer ; CBUF_CLR PROC FAR PUSH DI ;Save registers PUSH DX PUSH CX ; ;Get the bytes from the buffer MOV CX,GAUGE ;Get the count JCXZ CBUF_CLR_XIT ;Check for empty MOV DI,0 ;Initialize destination ; ;Loop to get all the bytes CBUF_CLR1: MOV AL,CBUF[SI] ;Get the character INC SI ;Increment the pointer CMP SI,CBUF_SIZ ;Wrap it? JNE CBUF_CLR2 ;Skip if no wrap MOV SI,0 ;Wrap the buffer pointer CBUF_CLR2: MOV LBUF[DI],AL ;Put the byte in linear buffer INC DI LOOP CBUF_CLR1 ;Loop until all bytes in LBUF ; ;Send the linear buffer to the disk MOV CX,GAUGE ;This is the number of bytes LEA DX,LBUF ;Here is where they are CALL WRIT_FIL ;Send them out MOV GAUGE,0 ;Set circular buffer empty CBUF_CLR_XIT: POP CX ;Restore registers POP DX POP DI RET CBUF_CLR ENDP ;------------------------------------------------------------------------------ ;Routine to handle output from a circular buffer ; CBUF_OUT PROC FAR CMP GAUGE,BLK_SIZ ;Any characters? JL CBUF_OUT_XIT ;If no, go ; ;Empty the buffer CALL COM_OFF ;Hold the com line CALL CBUF_CLR ;Clear the buffer JC CBUF_OUT_RET ;Error? CBUF_OUT_XIT: CLC ;Clear carry -- no exception CBUF_OUT_RET: RET CBUF_OUT ENDP ;------------------------------------------------------------------------------ ;Routine to save a file from a communications line to disk ; SAVE PROC FAR ; ;Set up return PUSH DS ;Save for proper return MOV AX,0 ;Point to beginning of segment PUSH AX ; for the offset ; ;Set up segments MOV DX,DS ;PSP was data segment MOV AX,DATAS ;New data segment MOV DS,AX ;Put in DS MOV ES,AX ; and in ES MOV WORD PTR DTA+2,DX ;Set the segment of the data ; ;Set up the file LEA DX,NAME_BUF ;Point to the ASCIIZ buffer CALL GET_SPEC ;Get file specifications JC EXCEPTION ;Error? LEA DX,NAME_BUF ;ASCIIZ buff had file specs CALL MAKE_FIL ;Set up the file JC EXCEPTION ;Error? MOV BX,AX ;Get the file handle ; ;Set up the communications line MOV DX,1 ;For COM1: MOV AL,0BBH ;2400,E,8,1 CALL COM_INIT ;Initialize it CALL COM_ON ; & turn it on CALL CBUF_INIT ;Initialize the circular buffer MOV DX,1 ;COM_2: ; ;Main loop for pulling in bytes SAV_LOOP: CALL CBUF_IN ;Check for input JC EXCEPTION ;Error or EOF? CALL CBUF_OUT ;Check to send it out JC EXCEPTION ;Error? JMP SAV_LOOP EXCEPTION: ;Error/Exception handler CMP AX,19 ;EOF? JE SAV_1 ;If so, close it up & return CALL EMSG_OUT ;Else report exception JMP SAV_XIT ; and return SAV_1: ;Normal return CALL COM_OFF ;Com line off CALL CBUF_CLR ;Clear the circular buffer JC EXCEPTION ;Error? CALL CLOS_FIL ;Close the file JC EXCEPTION ;Error? JMP SAV_XIT ;Exit SAV_XIT: CALL COM_ON ;Turn on com line RET SAVE ENDP ;------------------------------------------------------------------------------ CODES ENDS ; END ;_____________________________________________________________________________ ;>>>>> Physical EOF FILES.ASM <<<<<