Category : C Source Code
Archive   : FILTERS.ZIP
Filename : UPPER.ASM

Output of file : UPPER.ASM contained in archive : FILTERS.ZIP
Name upper
Title Lowercase to Uppercase filter.
page ,132
comment /

This program is a filter that translates all lowercase
characters to uppercase. It will optionally accept a
filename to read input from. All output goes to the
standard output device unless redirected.

Upper abc.txt read input from abc.txt,
output goes to screen.
Upper abc.txt >abcnew.txt
read input from abc.txt,
output goes to abcnew.txt.
Upper abcnew.txt
same as previous example
Upper abc.txt | find "ABC"
translates abc.txt to uppercase
and then searches the result
for the string "ABC".
Output goes to screen.
find "abc" abc.txt | upper | sort
Search abc.txt for all lines that
contain "abc". Translate all lines
selected and sort them, sending output
to the screen.
code segment public
; command line is at 80h of psp - first byte is length
org 80h
parmsize db ?
parm db 7fh dup (?)
; .com starts at 100h - but must jump around any data area
org 100h ; com file starts here
assume cs:code,ds:code,es:code
jmp clear
; data area for .com programs
handle dw 0h ; assume standard input
bufsiz equ 255
buffer db bufsiz dup (?)
; start of actual code is here (clear)
; now figure out which file to read from - parm line or standard input
cmp parmsize,0h ; if zero, no parm
jz again ; assume standard input
; parm length is not zero - assume the parm is a file name. If not
; found, quit.
mov al,parmsize ; get size of parm
xor ah,ah ; zero out top part of accum.
mov si,ax ; use length as a pointer into the dta
mov [si]+parm,0h ; to tack on a zero byte (asciiz).
; now try to open the file
lea dx,parm+1 ; address of 'filename'
mov al,0h ; open for read only
mov ah,3dh ; dos open function
int 21h ; invoke function
jc oops ; open error - quit
mov handle,ax ; save file handle
mov bx,handle ; read from standard input or file
mov cx,bufsiz ; # of characters to read
lea dx,buffer ; seg:off address of buffer area
mov ah,3fh ; dos read function
int 21h ; invoke function
jc oops ; error!
cmp ax,0h ; if zero, end of file
jz oops
push ax ; save copy of ax
mov cx,ax ; cx (and ax) contain # characters read
lea si,buffer ; offset of buffer
mov di,si ; di gets it too
lodsb ; get a character from buffer
cmp al,'a' ; if not between 'a' and 'z', skip
jl ok
cmp al,'z'
jg ok
sub al,20h ; else switch to uppercase
stosb ; put back into buffer
loop loop1 ; and repeat for entire buffer
pop cx ; restore character count
mov bx,1h ; standard output device
mov ah,40h ; dos write function
int 21h ; invoke dos function

jmp again ; repeat until end of file or error
int 20h ; return to dos
code ends
end upper

  3 Responses to “Category : C Source Code
Archive   : FILTERS.ZIP
Filename : UPPER.ASM

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: