Power-Programmierung/CD1.mdf/assemblr/library/usoftlib/show.asm

Assembly Source File | 1987-07-31 | 8.7 KB | 326 lines

      PAGE      60,132
      TITLE      SHOW

; Program SHOW.ASM
; Purpose Text file displayer
; Input      File name from command line or prompt
; Output  Display file to screen

      DOSSEG
      .MODEL  small

      INCLUDE dos.inc
      INCLUDE bios.inc

      .STACK  100h

      .DATA

; Status line

      PUBLIC  statline,linenum
statline  DB      " Line:         "
statfile  DB      " File:                "
stathelp  DB      " Quit: ESC    Move:   PGUP PGDN HOME END "
linenum      DW      1

; Variables for    screen handling

      PUBLIC  cell,rows,columns,vidadr,statatr,scrnatr,cga
cell      LABEL      WORD        ; Cell (character and attribute)
char      DB      " "        ; Initialize to    space
attr      DB      ?        ; Attribute

columns      EQU      80        ; Number of columns
rows      DW      24        ; Number of rows - status line takes one more
mode      DB      ?        ; Initial mode
pag      DB      ?        ; Initial display page
newvid      DB      0        ; Video    change flag
cga      DB      1        ; CGA flag - default yes

vidadr      DW      0B800h    ; Video    buffer address - default CGA
mono      EQU      0B000h    ; Monochrome address
statatr      DB      030h        ; Color    default    - black    on cyan
bwstat      EQU      070h        ; B&W default -    black on white
scrnatr      DB      017h        ; Color    default    - white    on blue
bwscrn      EQU      007h        ; B&W default -    white on black

; Variables for    buffer and file    handling

      PUBLIC  buffer,pbuffer,sbuffer,fsize,namebuf
buffer      LABEL      DWORD
pbuffer      DW      0        ; Position in buffer (offset)
sbuffer      DW      ?        ; Base of buffer (segment)
lbuffer      DW      ?        ; Length of buffer
fhandle      DW      ?        ; Holds    file handle on open
fsize      DW      ?        ; File size after dosopen

prompt      DB      13,10,13,10,"Enter filename: $"
prompt2      DB      13,10,"File problem. Try again? $"
namebuf      DB      66,?
filename  DB      66 DUP (0)        ; Buffer for file name

err1      DB      13,10,"Must have DOS 2.0 or higher",13,10,"$"
err2      DB      13,10,"File too big",13,10,"$"

; Call table

exkeys      DB      71,72,73,79,80,81    ; Extended key codes
lexkeys      EQU      $-exkeys        ; Table    of keys
extable      DW      homek
      DW      upk
      DW      pgupk
      DW      endk
      DW      downk
      DW      pgdnk
      DW      nonek

      .CODE
      EXTRN      pager:PROC,isEGA:PROC    ; Routines in other module
start:      mov      ax,@DATA        ; Initialize data segment
      mov      ds,ax

      cli                ; Turn off interrupts
      mov      ss,ax            ; Make SS and
      mov      sp,OFFSET STACK    ;   SP relative    to DGROUP
      sti

; Adjust memory    allocation

      mov      bx,sp            ; Convert stack    pointer    to paragraphs
      mov      cl,4            ;   to get stack size
      shr      bx,cl
      add      ax,bx            ; Add SS to get    end of program
      mov      bx,es            ; Get start of program
      sub      ax,bx            ; Subtract start from end
      @ModBlok ax            ; Release memory after program

; Allocate dynamic memory for file buffer

      @GetBlok 0FFFh        ; Try to allocate 64K
      mov      sbuffer,ax        ; Save buffer segment
      mov      lbuffer,bx        ; Save actual length allocated

; Check    DOS

      @GetVer            ; Get DOS version
      cmp      al,2            ; Requires DOS 2.0
      jge      video
      @DispStr err1            ;   else error and quit
      int      20h

; Adjust for current mode and and video    adapter

video:      call      isEGA            ; EGA (or VGA)?
      or      ax,ax            ; If 0 must be CGA or MA
      je      modechk        ; Leave    default
      mov      rows,ax        ; Load rows
      dec      cga            ; Not CGA

modechk:  @GetMode            ; Get video mode
      mov      mode,al        ; Save initial mode and    page
      mov      pag,bh
      mov      dl,al            ; Work on copy
      cmp      dl,7            ; Is it    mono 7?
      je      loadmono        ; Yes? Set mono
      cmp      dl,15            ; Is it    mono 15?
      jne      graphchk        ; No? Check graphics
loadmono: mov      vidadr,mono        ; Load mono address
      mov      statatr,bwstat    ; Set B&W defaults for status line
      mov      scrnatr,bwscrn    ;   and    screen background
      dec      cga            ; Not CGA
      cmp      al,15            ; Is it    mono 15?
      jne      cmdchk        ; No? Done
      mov      dl,7            ; Yes? Set standard mono
      jmp      SHORT    chmode

graphchk: cmp      dl,7            ; 7 or higher?
      jg      color            ; 8 to 14 are color (7 and 15 done)
      cmp      dl,4            ; 4 or higher?
      jg      bnw            ; 5 and    6 are probably black and white
      je      color            ; 4 is color
      test      dl,1            ; Even?
      jz      bnw            ; 0 and    2 are black and    white
color:                    ; 1 and    3 are color
      cmp      dl,3            ; 3?
      je      cmdchk        ; Yes? Done
      mov      dl,3            ; Change mode to 3
      jmp      SHORT    chmode

bnw:      mov      statatr,bwstat    ; Set B&W defaults for status line
      mov      scrnatr,bwscrn    ;   and    screen background
      cmp      dl,2            ; 2?
      je      cmdchk        ; Yes? Done
      mov      dl,2            ; Make it 2

chmode:      @SetMode dl            ; Set video mode
      @SetPage 0            ; Set video page
      mov      newvid,1        ; Set flag

; Try to open command line file

cmdchk:      mov      bl,es:[80h]        ; Get length
      sub      bh,bh
      mov      WORD PTR es:[bx+81h],0; Convert to ASCIIZ
      push      ds
      @OpenFil 82h,0,es        ; Open argument
      pop      ds
      jc      getname        ; If error, get    from prompt
      mov      fhandle,ax        ;   else save handle
      push      ds
      @GetFirst 82h,,es        ; Let DOS convert to file name
      pop      ds
      jnc      opened        ; If OK    file is    open

; Prompt for file

getname:  @DispStr prompt        ; Prompt for file
      @GetStr namebuf,0        ; Get response as ASCIIZ
      @OpenFil filename,0        ; Try to open response
      jc      badfile        ; If successful, continue
      mov      fhandle,ax        ; Save handle
      @GetFirst filename        ; Let DOS convert to file name
      jnc      opened        ; If OK, file is opened

badfile:  @DispStr prompt2        ;    else prompt to try    again
      @GetKey 0,1,0
      and      al,11011111b        ; Convert key to uppercase
      cmp      al,"Y"        ; If yes,
      je      getname        ;   try    again
      jmp      quit            ;   else quit

; Copy file name to status line

opened:      mov      si,9Eh        ; Load FCB as as source
      mov      di,OFFSET statfile[7]    ; Load status line as destination
      mov      al,es:[si]        ; Load first byte
      inc      si
copy:      mov      [di],al        ; Save and load    bytes until 0
      inc      di
      mov      al,es:[si]
      inc      si
      or      al,al            ; Check    for 0
      loopne  copy

; Check    file size

      @GetFilSz fhandle        ; Get file size

      or      dx,dx            ; Larger than 64K?
      jne      big            ; Yes? Too big
      mov      fsize,ax        ; Save file size
      mov      cx,4            ; Convert to paragraphs
      shr      ax,cl
      cmp      ax,lbuffer        ; Is it    larger than buffer
      jle      fileread        ; No? Continue

big:      @DispStr err2            ;   else error
      @Exit      2

fileread: push      ds
      @Read      buffer,fsize,fhandle    ; Read file
      pop      ds
      jnc      readok        ; If no    read error continue
      jmp      getname        ;   else try again

; Search back for EOF marker and adjust    if necessary

readok:      mov      di,ax            ; Load file length
      push      es            ; Save ES and load buffer segment
      mov      es,sbuffer
      std                ; Look backward    for 255    characters
      mov      cx,0FFh
      mov      al,1Ah        ; Search for EOF marker
      repne      scasb
      cld
      jcxz      noeof            ; If none, we're OK
      inc      di            ;   else adjust    and save file size
      mov      fsize,di

noeof:      pop      es
      @SetCurPos 0,43        ; Turn off cursor by moving off    screen

; Display first    page

      xor      ax,ax            ; Start    at 0
      push      ax
firstpg:  call      pager

; Handle keys

nextkey:  @GetKey 0,0,0            ; Get a    key
nextkey2: cmp      al,0            ; Is it    a null?
      je      extended        ; Yes? Must be extended    code

      cmp      al,27            ; Is it    ESCAPE?
      jne      nextkey        ; No? Ignore unknown command

quit:      @ClosFil fhandle        ; Yes? Close file
      @FreeBlok sbuffer        ; Release buffer
      cmp      newvid,1        ; Restore video?
      jne      thatsall        ; No?
      @SetMode mode            ; Restore video    mode, page, and    cursor
      @SetPage pag
thatsall: mov      dx,rows        ; Load last row    and first column
      xchg      dl,dh
      mov      cx,dx            ; Make row the same
      mov      dl,79
      @Scroll 0            ; Clear    last line
      sub      dl,dl
      @SetCurPos            ; Set cursor

      @Exit      0            ; Quit

extended: @GetKey 0,0,0            ; Get extended code
      push      es
      push      ds            ; Load DS into ES
      pop      es
      mov      di,OFFSET exkeys    ; Load address and length of key list
      mov      cx,lexkeys+1
      repne      scasb            ; Find position
      pop      es
      sub      di,(OFFSET exkeys)+1    ; Point    to key
      shl      di,1            ; Adjust pointer for word addresses
      call      extable[di]        ; Call procedure
      jmp      nextkey

homek:      mov      pbuffer,0        ; HOME - set position to 0
      push      pbuffer
      mov      linenum,1
      call      pager
      retn

upk:      mov      ax,-1            ; UP - scroll back 1 line
      push      ax
      call      pager
      retn

pgupk:      mov      ax,rows        ; PGUP - Page back
      neg      ax
      push      ax
      call      pager
      retn

endk:      mov      ax,fsize        ; END -    Get last byte of file
      mov      pbuffer,ax        ; Make it the file position
      mov      linenum,-1        ; Set illegal line number as flag
      mov      ax,rows        ; Page back
      neg      ax
      push      ax
      call      pager
      retn

downk:      mov      ax,1            ; DOWN - scroll    forward    1 line
      push      ax
      call      pager
      retn

pgdnk:      push      rows            ; PGDN - page forward
      call      pager
      retn

nonek:      retn                ; Ignore unknown key

      END     start