Programmer 7500/MAX_PROGRAMMERS.iso/INFO/ASMUTL/ASM002.ZIP/LIST80.ASM

Assembly Source File | 1985-05-11 | 10.4 KB | 399 lines

     PAGE     60,132
     TITLE     LIST --- Replace TYPE and MORE commands
;==============================================================================
; Name:     LIST, display contents of an ASCII file.
; Syntax:
;        LIST  <[d:][path]filename[.ext]>
; Input:
;        An ASCII file of any size may be listed, however only the
;        first 80 bytes of each record is displayed.
;
;        After the 'More?' prompt, enter a CR to continue, or
;        any other character to terminate.
; Output:
;        Logical records (ending in LF and/or CR) are placed into
;        the screen buffer.
; Notes:
;        Written for the IBM PC by Vernon Buerg, November 1983,
;        and is supplied for public domain use.
;
; Revised:  Robert S. Russell, Bootstrap Creations, Walnut Creek, Calif.
;        December 3, 1983 to allow enough space in buffer for filename
;        so that a path may also be specified.  Also removed a bug which
;        caused the system to lock if a carriage return is entered in
;        response to the filename prompt.
;
;==============================================================================
;
STACK     SEGMENT PARA STACK 'STACK'
     DB     128 DUP (0)
STACK     ENDS
;
DATA     SEGMENT PUBLIC PARA 'DATA'
ASKFILE  DB     13,10,'Enter [d:][path]filename[.ext]:$'             ;RSR
CLEAR     DB     27,'[2J$'
PROMPT     DB     27,'[25;1H','More?$'
EOFMSG     DB     27,'[25;1HEnd-of-file$'
CODE2     DB     13,10,'File not found$'                              ;RSR
CODE4     DB     13,10,'Too many open files$'                         ;RSR
KEYIN     DB     0          ;keyboard buffer size
KEYOUT     DB     0          ;keyboard length read
FILENAME DB     45 DUP (0)   ;drive:\path\filename.ext           ;RSR
HANDLE     DW     0          ;file handle from open
COL     DW     1          ;current display column
ROW     DW     2          ;current display row
INDEX     DW     0          ;offset in buffer to record
;
OPENMSG  DB     13,10,'Open code: '                                  ;RSR
OPENCODE DW     '00'
     DB     '  $'
RECLEN     DW     0          ;length of current record
RECADDR  DW     0          ;addr of i/o buffer
;
SWITCH1  DB     0
EOR     EQU     1          ;end-of-record
SWITCH2  DB     0
NODATA     EQU     2          ;null record
NUMLF     DB     0          ;line feed count
NUMCR     DB     0          ;C/R count
WORK     DB     256 DUP (?)  ;current logical record
DATA     ENDS
;
ZBUFFER  SEGMENT PARA PUBLIC 'BUFFER'
RECORDS  DB     65535 DUP (?)
ZBUFFER  ENDS
;
BIOS     SEGMENT AT 40H       ;set up labels to determine
     ORG     10H          ;color or monochrome card
EQFLAG     LABEL     WORD
     ORG     4AH          ;40 or 80 column display
NCLMS     LABEL     WORD
     ORG     63H
A6845     LABEL     WORD          ;points to video card ports
BIOS     ENDS
;
     PAGE
CSEG     SEGMENT PARA PUBLIC 'CODE'
     ASSUME  CS:CSEG,DS:DATA,SS:STACK,ES:ZBUFFER
LIST     PROC     FAR
     PUSH     DS          ;save for linkage
     XOR     AX,AX          ;clear for return
     PUSH     AX          ;put in stack
;
     MOV     AX,DATA      ;Addr of work areas
     MOV     DS,AX          ;Set data segment reg
;
     PUSH     DS          ;Save DS
     XOR     CX,CX          ;clear hi-byte
     MOV     CL,BYTE PTR ES:[80H]  ;Length of command parm
     DEC     CL          ;For ending CR
     CMP     CL,0          ;Any parm string?
     JLE     GETNAME      ;No, ask for it
;
     MOV     SI,82H       ;Offset to command parm string
     MOV     DI,OFFSET FILENAME
     MOV     AX,DS          ;Swap DS/ES
     MOV     BX,ES
     MOV     DS,BX          ;Copy command string
     MOV     ES,AX
     REP     MOVSB
     POP     DS          ;Restore DS
     JMP     OPEN
     PAGE
;  No filename supplied with command
;
GETNAME: POP     DS
RETRYNAME:                                ;RSR
     MOV     DX,OFFSET ASKFILE    ;Prompt for file name
     MOV     AH,9
     INT     21H
     MOV     AH,0AH       ;Buffered kybd input DOS req
     MOV     DX,OFFSET KEYIN
     MOV     KEYIN,44     ;Size of buffer                ;RSR
     INT     21H
;
     XOR     BX,BX
     MOV     BL,KEYOUT    ;Number of chars read
     CMP     BL,0
     JE     RETRYNAME                        ;RSR
     MOV     FILENAME[BX],0 ;overlay CR
     PAGE
;
OPEN:     MOV     DX,OFFSET FILENAME     ;file to open
     MOV     AX,0          ;for read only                ;RSR
     MOV     AH,3DH       ;open a file
     INT     21H
     MOV     HANDLE,AX    ;save file handle
;
     JNC     INIT          ;if OPEN okay
     MOV     DX,OFFSET CODE2
     CMP     AL,2          ;is it 'file not found'?
     JE     ERROR
     MOV     DX,OFFSET CODE4                    ;RSR
     CMP     AL,4          ;is it 'too many open files'?             ;RSR
     JE     ERROR
;
     AAM
     XCHG     AL,AH
     OR     OPENCODE,AX
     MOV     DX,OFFSET OPENMSG
ERROR:     MOV     AH,9
     INT     21H          ;say OPEN FAILED
     RET
     PAGE
;
; Initialize buffer to EOF stoppers
;
INIT:     MOV     BX,ZBUFFER   ;addr of I/O area
     MOV     RECADDR,BX   ;save it
     MOV     DX,OFFSET CLEAR
     MOV     AH,9
     INT     21H          ;to clear screen
;
READAGN: MOV     CX,65535     ;number of bytes to clear
     MOV     ES,RECADDR
;
STOPPER: MOV     DI,CX
     MOV     ES:BYTE PTR[DI],1AH    ;fill with stoppers
     LOOP     STOPPER
     PAGE
;
; Read a block    (64K)
;
     MOV     BX,HANDLE     ;get file handle from open
     MOV     DX,RECADDR     ;offset to record buffer
     PUSH     DS
     MOV     DS,DX         ;set data segment ptr
     SUB     DX,DX         ; with zero offset
     MOV     CX,65534     ;number of bytes to read
     MOV     AH,3FH      ;read from a file
     INT     21H
;
     POP     DS
;     MOV     BX,AX         ;Save length read
     MOV     SWITCH1,0     ;reset EOR flag
     MOV     INDEX,0     ;offset into buffer
     CMP     AX,0         ;Any bytes read?
     JNE     READ         ;Yes, list the buffer
     JMP     CLOSE         ;No, all done
;
; Set next row and column for next display line
;
READ:     MOV     CX,RECLEN     ;set column and row
     INC     CX         ; for next record
     MOV     AX,ROW
     DEC     AX
     CMP     NUMLF,0     ;record ended in LF?
     JE     SET         ;no, have col/row
     INC     AX         ;yes, row stays where it is
     MOV     CX,1         ; and in column 1
;
SET:     MOV     ROW,AX      ;set row
     MOV     COL,CX      ;set column
;
; Extract next logical record from display
;
GETNEXT: CALL     SCAN_BUF     ;Scan for logical record
     MOV     CX,RECLEN     ;Record size
     SUB     CL,NUMLF     ;for LF
     SUB     CL,NUMCR     ;for CR
     MOV     RECLEN,CX
     CMP     CX,0         ;blank line?
     JE     GETROW      ;yes, increment row only
;
     LEA     SI,WORK     ;addr of record
     MOV     AX,ROW      ;destination row
     CALL     PRINT         ;put into screen buffer
;
GETROW:  MOV     AX,ROW      ;get row again
     INC     AX         ;bump to next row
     MOV     ROW,AX      ;save row number
     CMP     AL,25         ;exceeded screen?
     JNE     TESTEOR     ;no, read next record
;
     MOV     DX,OFFSET PROMPT
     MOV     AH,9
     INT     21h         ;say 'More?'
;
; Wait for keyboard input
;
     MOV     AH,12         ;clear console
     MOV     AL,7         ;and get a char
     INT     21H         ;pause for enter
     CMP     AL,0DH      ;want to quit?
     JNE     CLOSE         ;yes, clean up
;
     MOV     ROW,2         ;no, reset to first row
     MOV     AX,ROW
;
     MOV     DX,OFFSET CLEAR
     MOV     AH,9
     INT     21H         ;to clear screen
;
     LEA     SI,WORK     ;addr of record
     MOV     AX,1         ;put last line on top
     MOV     CX,RECLEN
     CALL     PRINT         ;put into screen buffer
;
TESTEOR: TEST     SWITCH1,EOR     ;end-of-records?
     JZ     READ
     JMP     READAGN     ;yes, read next block
;
CLOSE:     MOV     BX,HANDLE     ;file handle from open
     MOV     AH,3EH      ;close a file handle
     INT     21H
;
     MOV     DX,OFFSET EOFMSG
     MOV     AH,9
     INT     21H         ;to say done
;
     RET
     PAGE
SCAN_BUF PROC     NEAR
;
; Function: Scan the buffer for special characters and copy wanted
;     data to field WORK. A logical record ends in an LF and/or CR.
;
; Input: ZBUFFER (RECORDS) contains a block of data from the file
;     INDEX is the current offset to a logical record
; Output:
;     WORK contains a logical record
;     NUMLF contains number of line feeds (ignored)
;     NUMCR contains number of carriage returns (ignored)
;     RECLEN contains length of logical record
; Notes: Tabs are replaced by blanks;
;     lines beginning with hex-F are ignored
;
     PUSH     ES
     PUSH     CX
     PUSH     SI
     PUSH     DI
     TEST     SWITCH1,EOR
     JZ     SCAN1
     JMP     SCAN_END
;
SCAN1:     XOR     CX,CX
     XOR     DI,DI
     AND     SWITCH2,0FFH-NODATA
     MOV     NUMLF,0     ;reset LF indicator
     MOV     NUMCR,0     ;zero CR counter
     MOV     AX,ZBUFFER
     MOV     ES,AX         ;set addr of I/O buffer segment
;
SCAN2:     MOV     SI,INDEX
     MOV     AL,RECORDS[SI]  ;Get a byte
     CMP     AL,1AH      ;End of buffer?
     JNE     SCAN3
     MOV     RECLEN,CX
     OR     SWITCH1,EOR     ;Indicate end-of-records
     JMP     SCAN_END
;
SCAN3:     CMP     AL,9H         ;Is it TAB?
     JNE     SCAN4
     MOV     AL,' '          ;Yes, replace with blank
;
SCAN4:     MOV     WORK[DI],AL     ;Store character
     INC     DI         ;Increment pointer
     INC     CX         ;Increment counter
     INC     INDEX         ;Increment counter
;
     CMP     AL,0DH      ;Is it a CR?
     JNE     SCAN5
     INC     NUMCR         ;Yes, increment counter
SCAN5:     CMP     AL,' '
     JE     SCAN7
     CMP     AL,0AH      ;Is it line feed?
     JNE     SCAN6
     INC     NUMLF
     JMP     SCAN8
SCAN6:     OR     SWITCH2,NODATA  ;Non-space found
;
SCAN7:     CMP     CX,255      ;Record too big?
     JE     SCAN8         ;Chop record at 255 bytes
     JMP     SCAN2
;
SCAN8:     MOV     RECLEN,CX
     CMP     WORK,0FH     ;If record begins with "sun"
     JNE     SCAN9         ; symbol, skip it
     JMP     SCAN1
;
SCAN9:     TEST     SWITCH2,NODATA  ;If nothing but spaces found,
     JNZ     SCAN_END     ; read another record
     JMP     SCAN1
;
SCAN_END:
     POP     DI
     POP     SI
     POP     CX
     POP     ES
     RET
;
SCAN_BUF ENDP
;
     PAGE
     ASSUME  CS:CSEG,DS:DATA,ES:NOTHING
PRINT     PROC     NEAR
     PUSH     ES
     PUSH     DI
     PUSH     DX
     PUSH     SI
;
     MOV     DI,COL      ;set column
     DEC     DI         ;adjust for zero offset
     DEC     AX         ;adjust row too
     CMP     CL,0         ;null string?
     JE     EXIT         ;if so,do nothing, Else,
;
     MOV     BX,BIOS     ;get ready to determine card type
     MOV     ES,BX         ;and number of columns
     MUL     ES:NCLMS     ;AX = column * words per line
     ADD     DI,AX         ;DI = words from start of screen
     SHL     DI,1         ;adjust for attribute bytes
;
     MOV     DX,ES:A6845     ;point to 6845 base port
     ADD     DX,6         ;point to status port
;
;CX has the count of characters to write,
;SI points to the string data,
;DI points to a screen position
;
     MOV     AX,0B800H     ;default to color card
     MOV     BX,ES:EQFLAG
     AND     BX,30H
     CMP     BX,30H      ;is it monochrome?
     JNE     CARDOK      ;no, go
     MOV     AX,0B000H     ;yes, set for monochrome
CARDOK:  MOV     ES,AX         ;points ES to video
;
;  DS:SI => first character of string
;  ES:DI => screen memory to display it
;  CX     => number of characters to display
;  DX     => status port of video card
;
;-------- Wait for horzontal retrace
TESTLO:  IN     AL,DX         ;get status
     TEST     AL,1         ;is it low?
     JNZ     TESTLO      ;no, keep checking
     CLI             ;turn off interrupts
TESTHI:  IN     AL,DX         ;get status
     TEST     AL,1         ;is it high?
     JZ     TESTHI      ;no, keep checking
;-------- Okay to write to screen now (no 'hash')
     MOVSB             ;[DS:DI]->[ES:DI],DI++,SI++,CX--
     INC     DI         ;skip the attribute byte
     LOOP     TESTLO      ;do till end of string
     STI             ;turn interrupts back on
;
EXIT:     POP     SI
     POP     DX
     POP     DI
     POP     ES
     RET
;
PRINT     ENDP
;
LIST     ENDP
CSEG     ENDS
;
     END     LIST